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Revision as of 01:56, 4 March 2015 editSeppi333 (talk | contribs)Autopatrolled, Extended confirmed users, Page movers, New page reviewers, Pending changes reviewers, Template editors35,345 edits ce		Latest revision as of 22:46, 10 December 2024 edit Elysiajous (talk | contribs)303 edits Removed many routes of administration from the infobox because they are either routes of administration of various chemically modified versions of testosterone (in the case of injection) or not FDA approved methods of administration (vaginal, rectal, oral)Tag: Visual edit
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			{{Short description|Medication and naturally occurring steroid hormone}}
	{{Use mdy dates|date=February 2015}}
			{{About|testosterone as a medication|the natural hormone|Testosterone}}
	{{Drugbox| Verifiedfields = changed
			{{Redirect|Testavan|the wine-tasting accessory|Tastevin}}
			{{Use mdy dates|date=February 2024}}
			{{cs1 config|name-list-style=vanc|display-authors=6}}
			{{Drugbox
	| Watchedfields = changed		| Watchedfields = changed
	| verifiedrevid = 420412587		| verifiedrevid = 649778658
			| drug_name = Testosterone
	| IUPAC_name = (8''R'',9''S'',10''R'',13''S'',14''S'',17''S'')- 17-Hydroxy-10,13-dimethyl- 1,2,6,7,8,9,11,12,14,15,16,17- dodecahydrocyclopentaphenanthren-3-one
	| image = Testosteron.svg		| image = Testosteron.svg
	| width = 200px		| width = 225
			| alt =
	| image2 = Testosterone-from-xtal-3D-balls.png
			| image2 = Testosterone molecule ball.png
			| width2 = 225
	<!--Clinical data-->
			| alt2 =
	| tradename = Androderm, Delatestryl
			| caption = <!-- Clinical data -->
			| pronounce = {{IPAc-en|t|ɛ|ˈ|s|t|ɒ|s|t|ə|r|oʊ|n}} {{respell|teh|STOS|tə|rohn}}<ref>. ].</ref>
			| tradename = AndroGel, Testim, TestoGel, ]
	| Drugs.com = {{drugs.com|monograph|testosterone}}		| Drugs.com = {{drugs.com|monograph|testosterone}}
	| pregnancy_US = X		| MedlinePlus = a619028
			| DailyMedID = Testosterone
	| pregnancy_category = ] due to ]ic effects
			| pregnancy_AU = D
	| legal_US = Schedule III
			| pregnancy_AU_comment = <ref name="Drugs.com pregnancy">{{cite web | title=Testosterone Use During Pregnancy | website=Drugs.com | date=August 20, 2019 | url=https://www.drugs.com/pregnancy/testosterone.html | access-date=January 8, 2020 | archive-date=February 1, 2014 | archive-url=https://web.archive.org/web/20140201201902/http://www.drugs.com/pregnancy/testosterone.html | url-status=live }}</ref>
	| legal_CA = Schedule IV
			| pregnancy_category = ] due to ]ic effects
	| licence_US = Testosterone
			| addiction_liability = Moderate <ref name="d982">{{cite web | title=Anabolic steroid misuse | website=nhs.uk | date=2022-11-04 | url=https://www.nhs.uk/conditions/anabolic-steroid-misuse/ | access-date=2024-07-12}}</ref>
			| routes_of_administration = ], ], ], ] (], ], ]).
			| class = ], ]
			| ATC_prefix = G03
			| ATC_suffix = BA03
			| ATC_supplemental = <!-- Legal status -->
			| legal_AU = <!-- S2, S3, S4, S5, S6, S7, S8, S9 or Unscheduled-->{{Citation needed|date=August 2023}}
			| legal_AU_comment =
			| legal_BR = C5
			| legal_BR_comment = <ref>{{Cite web |author=Anvisa |author-link=Brazilian Health Regulatory Agency |date=March 31, 2023 |title=RDC Nº 784 - Listas de Substâncias Entorpecentes, Psicotrópicas, Precursoras e Outras sob Controle Especial |trans-title=Collegiate Board Resolution No. 784 - Lists of Narcotic, Psychotropic, Precursor, and Other Substances under Special Control|url=https://www.in.gov.br/en/web/dou/-/resolucao-rdc-n-784-de-31-de-marco-de-2023-474904992 |url-status=live |archive-url=https://web.archive.org/web/20230803143925/https://www.in.gov.br/en/web/dou/-/resolucao-rdc-n-784-de-31-de-marco-de-2023-474904992 |archive-date=August 3, 2023 |access-date=August 15, 2023 |publisher=] |language=pt-BR |publication-date=April 4, 2023}}</ref>
			| legal_CA = Schedule IV{{citation needed|date=August 2023}}
			| legal_CA_comment =
			| legal_DE = <!-- Anlage I, II, III or Unscheduled-->{{citation needed|date=August 2023}}
			| legal_DE_comment =
			| legal_NZ = <!-- Class A, B, C -->{{citation needed|date=August 2023}}
			| legal_NZ_comment =
			| legal_UK = Class C{{citation needed|date=August 2023}}
			| legal_UK_comment =
			| legal_US = Schedule III{{citation needed|date=August 2023}}
			| legal_US_comment =
			| legal_EU = Rx-only
			| legal_EU_comment = <ref>{{cite web | author = Human Medicines Evaluation Division | title = Active substance: testosterone (all formulations apart from topical use) | url = https://www.ema.europa.eu/documents/psusa/testosterone-all-formulations-apart-topical-use-list-nationally-authorised-medicinal-products-psusa/00010631/202112_en.pdf | work= List of nationally authorised medicinal products | publisher = European Medicines Agency | date = September 1, 2022 | access-date = September 6, 2022 | archive-date = September 6, 2022 | archive-url = https://web.archive.org/web/20220906054434/https://www.ema.europa.eu/en/documents/psusa/testosterone-all-formulations-apart-topical-use-list-nationally-authorised-medicinal-products-psusa/00010631/202112_en.pdf | url-status = live }}</ref><ref>{{cite web | author = Human Medicines Evaluation Division | title = Active substance: testosterone (topical use) | url = https://www.ema.europa.eu/documents/psusa/testosterone-topical-use-list-nationally-authorised-medicinal-products-psusa/00002908/202112_en.pdf | work= List of nationally authorised medicinal products | publisher = European Medicines Agency | date = September 1, 2022 | access-date = September 6, 2022 | archive-date = September 6, 2022 | archive-url = https://web.archive.org/web/20220906054434/https://www.ema.europa.eu/en/documents/psusa/testosterone-topical-use-list-nationally-authorised-medicinal-products-psusa/00002908/202112_en.pdf | url-status = live }}</ref>
			| legal_UN = <!-- N I, II, III, IV / P I, II, III, IV-->{{citation needed|date=August 2023}}
			| legal_UN_comment =
	| legal_status = Rx-only		| legal_status = Rx-only
	| routes_of_administration = Intramuscular injection, transdermal (cream, gel, or patch), sub-'Q' pellet
			<!-- Pharmacokinetic data -->| dependency_liability = Moderate <ref name="d982">{{cite web | title=Anabolic steroid misuse | website=nhs.uk | date=2022-11-04 | url=https://www.nhs.uk/conditions/anabolic-steroid-misuse/ | access-date=2024-07-12}}</ref>
	<!--Pharmacokinetic data-->
	| bioavailability = Low (due to extensive ])		| bioavailability = Oral: very low (due to extensive ])
			| protein_bound = 97.0–99.5% (to {{abbrlink|SHBG|sex hormone-binding globulin}} and ])<ref name="MelmedPolonsky2015">{{cite book|vauthors=Melmed S, Polonsky KS, Larsen PR|title=Williams Textbook of Endocrinology|url=https://books.google.com/books?id=iPIACwAAQBAJ&pg=PA709|date=November 11, 2015|publisher=Elsevier Health Sciences|isbn=978-0-323-34157-8|pages=709, 711, 765|access-date=November 18, 2016|archive-date=April 14, 2019|archive-url=https://web.archive.org/web/20190414214954/https://books.google.com/books?id=iPIACwAAQBAJ&pg=PA709|url-status=live}}</ref>
	| metabolism = ], ] and ]
			| metabolism = ] (mainly ] and ])
	| elimination_half-life = 2–4&nbsp;hours
			| metabolites =
	| excretion = ] (90%), feces (6%)
			| onset =
			| elimination_half-life = 2–4&nbsp;hours{{Citation needed|date=October 2016}}
			| duration_of_action =
			| excretion = ] (90%), ] (6%)
	<!--Identifiers-->		<!-- Identifiers -->| CAS_number_Ref = {{cascite|correct|CAS}}
	| CAS_number_Ref = {{cascite|correct|CAS}}
	| CAS_number = 58-22-0		| CAS_number = 58-22-0
	| CAS_supplemental = <br/>{{CAS|57-85-2}} (propionate ester) <!-- Also CAS verified -->		| CAS_supplemental = <br />{{CAS|57-85-2}} (])<!-- Also CAS verified --><br />{{CAS|315-37-7}} (])<br />{{CAS|58-20-8}} (])<br />{{CAS|5949-44-0}} (])
	| ATC_prefix = G03
	| ATC_suffix = BA03
	| ChEBI_Ref = {{ebicite|correct|EBI}}
	| ChEBI = 17347
	| PubChem = 6013		| PubChem = 6013
	| IUPHAR_ligand = 2858		| IUPHAR_ligand = 2858
Line 43:		Line 72:
	| KEGG_Ref = {{keggcite|correct|kegg}}		| KEGG_Ref = {{keggcite|correct|kegg}}
	| KEGG = D00075		| KEGG = D00075
			| ChEBI_Ref = {{ebicite|correct|EBI}}
			| ChEBI = 17347
	| ChEMBL_Ref = {{ebicite|correct|EBI}}		| ChEMBL_Ref = {{ebicite|correct|EBI}}
	| ChEMBL = 386630		| ChEMBL = 386630
			| NIAID_ChemDB =
			| PDB_ligand =
			| synonyms = Androst-4-en-17β-ol-3-one
			<!-- Chemical and physical data -->| IUPAC_name = (8''R'',9''S'',10''R'',13''S'',14''S'',17''S'')-17-hydroxy-10,13-dimethyl-1,2,6,7,8,9,11,12,14,15,16,17-dodecahydrocyclopentaphenanthren-3-one
	<!--Chemical data-->
	| C=19 | H=28 | O=2		| C = 19
			| H = 28
	| molecular_weight = 288.42
			| O = 2
	| smiles = O=C4\C=C2/(1CC3((O)CC31CC2)C)(C)CC4
			| SMILES = O=C4\C=C2/(1CC3((O)CC31CC2)C)(C)CC4
	| StdInChI_Ref = {{stdinchicite|correct|chemspider}}		| StdInChI_Ref = {{stdinchicite|correct|chemspider}}
	| StdInChI = 1S/C19H28O2/c1-18-9-7-13(20)11-12(18)3-4-14-15-5-6-17(21)19(15,2)10-8-16(14)18/h11,14-17,21H,3-10H2,1-2H3/t14-,15-,16-,17-,18-,19-/m0/s1		| StdInChI = 1S/C19H28O2/c1-18-9-7-13(20)11-12(18)3-4-14-15-5-6-17(21)19(15,2)10-8-16(14)18/h11,14-17,21H,3-10H2,1-2H3/t14-,15-,16-,17-,18-,19-/m0/s1
			| StdInChI_comment =
	| StdInChIKey_Ref = {{stdinchicite|correct|chemspider}}		| StdInChIKey_Ref = {{stdinchicite|correct|chemspider}}
	| StdInChIKey = MUMGGOZAMZWBJJ-DYKIIFRCSA-N		| StdInChIKey = MUMGGOZAMZWBJJ-DYKIIFRCSA-N
			| density =
			| density_notes =
	| melting_point = 155		| melting_point = 155
			| melting_high =
			| melting_notes =
			| boiling_point =
			| boiling_notes =
			| solubility =
			| sol_units =
	| specific_rotation = +110.2°		| specific_rotation = +110.2°
	| sec_combustion = −11080 kJ/mol
	}}		}}
			<!-- Definition and medical uses -->
	'''Testosterone''' is a ] from the ] group and is found in humans and other ]. In humans and other ]s, testosterone is secreted primarily by the ] of ]s and, to a lesser extent, the ] of ]s. Small amounts are also secreted by the ]s. It is the principal male sex ] and an ].
			'''Testosterone''' ('''T''') is a ] and naturally occurring ].<ref name=AHFS2016/> It is used to treat ], ], and certain types of ].<ref name=AHFS2016/><ref>{{cite web |title=List of Gender Dysphoria Medications (6 Compared) |url=https://www.drugs.com/condition/gender-dysphoria.html |website=Drugs.com |access-date=May 6, 2020 |language=en |archive-date=April 26, 2020 |archive-url=https://web.archive.org/web/20200426180544/https://www.drugs.com/condition/gender-dysphoria.html |url-status=live }}</ref> It may also be used to increase ] in the form of ].<ref name=AHFS2016/> It is unclear if the use of testosterone for ] is beneficial or harmful.<ref name=FDA2015>{{cite web |author=Staff |title=Testosterone Products: Drug Safety Communication – FDA Cautions About Using Testosterone Products for Low Testosterone Due to Aging; Requires Labeling Change to Inform of Possible Increased Risk of Heart Attack And Stroke |url=https://www.fda.gov/Safety/MedWatch/SafetyInformation/SafetyAlertsforHumanMedicalProducts/ucm436280.htm |date=March 3, 2015 |work=] |access-date=March 5, 2015 |url-status=live |archive-url=https://web.archive.org/web/20150305015556/https://www.fda.gov/Safety/MedWatch/SafetyInformation/SafetyAlertsforHumanMedicalProducts/ucm436280.htm |archive-date=March 5, 2015}}</ref> Testosterone can be administered through several different routes, including ] ] or ], ] subdermal implants, or ].<ref name=AHFS2016/>
			<!-- Side effects -->
	In men, testosterone plays a key role in the development of male reproductive tissues such as the ] and ] as well as promoting secondary sexual characteristics such as increased ], ] mass, and the growth of ].<ref name="Mooradian_ 1987">{{cite journal | author = Mooradian AD, Morley JE, Korenman SG | title = Biological actions of androgens | journal = Endocr. Rev. | volume = 8 | issue = 1 | pages = 1–28 | date = February 1987 | pmid = 3549275 | doi = 10.1210/edrv-8-1-1 | url = }}</ref> In addition, testosterone is essential for health and well-being<ref name="pmid19707253">{{cite journal | author = Bassil N, Alkaade S, Morley JE | title = The benefits and risks of testosterone replacement therapy: a review | journal = Ther Clin Risk Manag | volume = 5 | issue = 3 | pages = 427–48 | date = June 2009 | pmid = 19707253 | pmc = 2701485 | doi = | url = }}</ref> as well as the prevention of ].<ref name="pmid19011293">{{cite journal | author = Tuck SP, Francis RM | title = Testosterone, bone and osteoporosis | journal = Front Horm Res | volume = 37 | issue = | pages = 123–32 | year = 2009 | pmid = 19011293 | doi = 10.1159/000176049 | isbn = 978-3-8055-8622-1 | series = Frontiers of Hormone Research }}</ref>
			Common ]s of testosterone include ], ], and ].<ref name=AHFS2016/> Serious side effects may include ], ], and behavioral changes.<ref name=AHFS2016/> Women and children who are exposed may develop ].<ref name=AHFS2016/> It is recommended that individuals with ] should not use the medication.<ref name=AHFS2016/> It can cause harm to the baby if used during ] or ].<ref name=AHFS2016/> Testosterone is in the ] family of medications.<ref name=AHFS2016/>
			<!-- History, society and culture -->
	On average, in adult males, levels of testosterone are about 7–8 times as great as in adult females,<ref name="pmid14981046">{{cite journal | author = Torjesen PA, Sandnes L | title = Serum testosterone in women as measured by an automated immunoassay and a RIA | journal = Clin. Chem. | volume = 50 | issue = 3 | pages = 678; author reply 678–9 | date = March 2004 | pmid = 14981046 | doi = 10.1373/clinchem.2003.027565 }}</ref> but, as the metabolic consumption of testosterone in males is greater, the daily production is about 20 times greater in men.<ref name="pmid6025472">{{cite journal | author = Southren AL, Gordon GG, Tochimoto S, Pinzon G, Lane DR, Stypulkowski W | title = Mean plasma concentration, metabolic clearance and basal plasma production rates of testosterone in normal young men and women using a constant infusion procedure: effect of time of day and plasma concentration on the metabolic clearance rate of testosterone | journal = J. Clin. Endocrinol. Metab. | volume = 27 | issue = 5 | pages = 686–94 | date = May 1967 | pmid = 6025472 | doi = 10.1210/jcem-27-5-686 }}</ref><ref name="pmid5843701">{{cite journal | author = Southren AL, Tochimoto S, Carmody NC, Isurugi K | title = Plasma production rates of testosterone in normal adult men and women and in patients with the syndrome of feminizing testes | journal = J. Clin. Endocrinol. Metab. | volume = 25 | issue = 11 | pages = 1441–50 | date = November 1965 | pmid = 5843701 | doi = 10.1210/jcem-25-11-1441 }}</ref> Females are also more sensitive to the hormone.<ref name="isbn0-07-135739-4">{{cite book | author = Dabbs M, Dabbs JM | authorlink = | editor = | others = | title = Heroes, rogues, and lovers: testosterone and behavior | edition = | language = | publisher = McGraw-Hill | location = New York | year = 2000 | origyear = | pages = | quote = | isbn = 0-07-135739-4 | oclc = | doi = | url = | accessdate = }}</ref> Testosterone is observed in most vertebrates. ] make a slightly different form called ].<ref name="isbn0-87893-617-3">{{cite book | author = Nelson, Randy F. | authorlink = | editor = | others = | title = An introduction to behavioral endocrinology | edition = | language = | publisher = Sinauer Associates | location = Sunderland, Mass | year = 2005 | origyear = | page = 143 | quote = | isbn = 0-87893-617-3 | oclc = | doi = | url = | accessdate = }}</ref> Its counterpart in insects is ].<ref name="De_Loof_2006">{{cite journal | author = De Loof A | title = Ecdysteroids: the overlooked sex steroids of insects? Males: the black box | journal = Insect Science |date=October 2006 | volume = 13 | issue = 5 | pages = 325–338 | doi = 10.1111/j.1744-7917.2006.00101.x }}</ref> These ubiquitous steroids suggest that ]s have an ancient evolutionary history.<ref name="Mechoulam_1984">{{cite journal | author = Mechoulam R, Brueggemeier RW, Denlinger DL | title = Estrogens in insects | journal = Journal Cellular and Molecular Life Sciences |date=September 1984 | volume = 40 | issue = 9 | pages = 942–944 | doi = 10.1007/BF01946450 }}</ref>
			Testosterone was first isolated in 1935, and approved for medical use in 1939.<ref>{{cite book | vauthors = Taylor WN | title = Anabolic Steroids and the Athlete | date = 2002 | publisher = McFarland | isbn = 978-0-7864-1128-3 | page = 180 | edition = 2nd | url = https://books.google.com/books?id=OGcQ0Tp2AFcC&pg=PA180 | url-status = live | archive-url = https://web.archive.org/web/20160914142007/https://books.google.com/books?id=OGcQ0Tp2AFcC&pg=PA180 | archive-date = September 14, 2016}}</ref><ref name=Fis2006>{{cite book |vauthors=Fischer J, Ganellin CR |title=Analogue-based Drug Discovery |date=2006 |publisher=John Wiley & Sons |isbn=9783527607495 |page=481 |url=https://books.google.com/books?id=FjKfqkaKkAAC&pg=PA481 |language=en |access-date=August 18, 2020 |archive-date=August 23, 2022 |archive-url=https://web.archive.org/web/20220823114136/https://books.google.com/books?id=FjKfqkaKkAAC&pg=PA481 |url-status=live }}</ref> Rates of use have increased three times in the United States between 2001 and 2011.<ref name=Des2016>{{cite journal | vauthors = Desroches B, Kohn TP, Welliver C, Pastuszak AW | title = Testosterone therapy in the new era of Food and Drug Administration oversight | journal = Translational Andrology and Urology | volume = 5 | issue = 2 | pages = 207–12 | date = April 2016 | pmid = 27141448 | pmc = 4837303 | doi = 10.21037/tau.2016.03.13 | doi-access = free }}</ref> It is on the ].<ref name="WHO21st">{{cite book | vauthors = ((World Health Organization)) | title = World Health Organization model list of essential medicines: 21st list 2019 | year = 2019 | hdl = 10665/325771 | author-link = World Health Organization | publisher = World Health Organization | location = Geneva | id = WHO/MVP/EMP/IAU/2019.06. License: CC BY-NC-SA 3.0 IGO }}</ref> It is available as a ].<ref name=AHFS2016>{{cite web |title=Testosterone|url=https://www.drugs.com/monograph/testosterone.html|website=Drugs.com |publisher=American Society of Health-System Pharmacists|access-date=September 3, 2016|date=December 4, 2015 |archive-url=https://web.archive.org/web/20160820173417/https://www.drugs.com/monograph/testosterone.html |archive-date=August 20, 2016|url-status=live}}</ref> In 2022, it was the 118th most commonly prescribed medication in the United States, with more than 5{{nbsp}}million prescriptions.<ref>{{cite web | title=The Top 300 of 2022 | url=https://clincalc.com/DrugStats/Top300Drugs.aspx | website=ClinCalc | access-date=30 August 2024 | archive-date=30 August 2024 | archive-url=https://web.archive.org/web/20240830202410/https://clincalc.com/DrugStats/Top300Drugs.aspx | url-status=live }}</ref><ref>{{cite web | title = Testosterone Drug Usage Statistics, United States, 2013 - 2022 | website = ClinCalc | url = https://clincalc.com/DrugStats/Drugs/Testosterone | access-date = 30 August 2024 }}</ref>
	{{TOC limit|3}}
			{{TOC limit}}
			==Medical uses==
	== Health effects ==
			{{See also|Androgen replacement therapy#Medical uses|Anabolic steroid#Medical}}
	In general, ] promote ] and growth of those tissues with ]. Testosterone effects can be classified as ] and ], though the distinction is somewhat artificial, as many of the effects can be considered both.
			The primary use of testosterone is the treatment of males with too little or no natural testosterone production, also termed ] or ] (androgen deficiency).<ref>{{cite journal | vauthors = Margo K, Winn R | title = Testosterone treatments: why, when, and how? | journal = American Family Physician | volume = 73 | issue = 9 | pages = 1591–8 | date = May 2006 | pmid = 16719252 | url = http://www.aafp.org/afp/2006/0501/p1591.html | access-date = October 3, 2016 | url-status = live | archive-url = https://web.archive.org/web/20161003184639/http://www.aafp.org/afp/2006/0501/p1591.html | archive-date = October 3, 2016 }}</ref> This treatment is referred to as ] (HRT), or alternatively, and more specifically, as testosterone replacement therapy (TRT) or ] (ART). It is used to maintain serum testosterone levels in the normal male range. Decline of testosterone production with age has led to interest in testosterone supplementation.<ref name="pmid16985841">{{cite journal | vauthors = Myers JB, Meacham RB | title = Androgen replacement therapy in the aging male | journal = Reviews in Urology | volume = 5 | issue = 4 | pages = 216–26 | year = 2003 | pmid = 16985841 | pmc = 1508369 }}</ref>
	* ''Anabolic effects'' include growth of ] and strength, increased ] and strength, and stimulation of linear growth and ].
	* ''Androgenic effects'' include ] of the ], particularly the ] and the formation of the ] in the fetus, and after birth (usually at ]) a deepening of the ], growth of the ] and ]. Many of these fall into the category of male ].
			A 2020 guideline from the ] supports the discussion of testosterone in adult men with age-related ] who have ]. They recommend yearly evaluation regarding possible improvement and, if none, to discontinue testosterone; physicians should consider intramuscular treatments, rather than transdermal treatments, due to costs and since the effectiveness and harm of either method is similar. Testosterone treatment for reasons other than possible improvement of sexual dysfunction may not be recommended.<ref name="ANN-20200106">{{cite journal | vauthors = Qaseem A, Horwitch CA, Vijan S, Etxeandia-Ikobaltzeta I, Kansagara D | title = Testosterone Treatment in Adult Men With Age-Related Low Testosterone: A Clinical Guideline From the American College of Physicians | journal = Annals of Internal Medicine | date = January 2020 | volume = 172 | issue = 2 | pages = 126–133 | pmid = 31905405 | doi = 10.7326/M19-0882 | doi-access = free }}</ref><ref name="MSCP-20200107">{{cite news |vauthors=Parry NM |title=New Guideline for Testosterone Treatment in Men With 'Low T' |url=https://www.medscape.com/viewarticle/923449 |date=January 7, 2020 |work=Medscape.com |access-date=January 7, 2020 |url-status=live |archive-date=January 8, 2020 |archive-url=https://web.archive.org/web/20200108011908/https://www.medscape.com/viewarticle/923449}}</ref>
	Testosterone effects can also be classified by the age of usual occurrence. For ] effects in both males and females, these are mostly dependent on the levels and duration of circulating free testosterone.
	=== Before birth ===		===Deficiency===
			{{Further|Hypogonadism#Treatment|Androgen deficiency#Treatment}}
	The ''prenatal androgen effects'' occur during two different stages. Between 4 and 6 weeks of the gestation.
	*Genital virilization (midline fusion, ] ], scrotal thinning and rugation, ] enlargement); although the role of testosterone is far smaller than that of ].
	*Development of ] and ]s.
			Testosterone deficiency (also termed hypotestosteronism or hypotestosteronemia) is an abnormally low testosterone production. It may occur because of testicular dysfunction (]) or hypothalamic–pituitary dysfunction (]) and may be ] or acquired.<ref name="e930">{{cite book | vauthors = Sizar O, Leslie SW, Schwartz J | chapter = Male Hypogonadism | title = StatPearls | publisher=StatPearls Publishing | date=25 Feb 2024 | pmid=30422528 | chapter-url=https://www.ncbi.nlm.nih.gov/books/NBK532933/ | access-date=30 Aug 2024}}</ref>
	During the second trimester, androgen level is associated with ] formation.<ref name="pmid19403051">{{cite journal | author = Swaab DF, Garcia-Falgueras A | title = Sexual differentiation of the human brain in relation to gender identity and sexual orientation | journal = Funct. Neurol. | volume = 24 | issue = 1 | pages = 17–28 | year = 2009 | pmid = 19403051 | doi = }}</ref> This period affects the femininization or masculinization of the fetus and can be a better predictor of feminine or masculine behaviours such as sex typed behaviour than an adult's own levels. A mother's testosterone level during pregnancy is correlated with her daughter's sex-typical behavior as an adult, and the correlation is even stronger than with the daughter's own adult testosterone level.<ref name="isbn0-8135-3053-9">{{cite book | author = Browne KR | title = Biology at work: rethinking sexual equality | publisher = Rutgers University Press | location = New Brunswick, N.J | year = 2002 | page = 112 | isbn = 0-8135-3053-9 | url = http://books.google.com/books?id=vq_0BUkcZ5MC&lpg=PP1&dq=Biology%20at%20Work%3A%20Rethinking%20Sexual%20Equality&pg=PA112#v=onepage&q&f=false }}</ref>
			{{Androgen replacement therapy formulations and dosages used in men}}
	=== Early infancy ===
	''Early infancy androgen effects'' are the least understood. In the first weeks of life for male infants, testosterone levels rise. The levels remain in a pubertal range for a few months, but usually reach the barely detectable levels of childhood by 4–6 months of age.<ref name="pmid4715291">{{cite journal | author = Forest MG, Cathiard AM, Bertrand JA | title = Evidence of testicular activity in early infancy | journal = J. Clin. Endocrinol. Metab. | volume = 37 | issue = 1 | pages = 148–51 | date = July 1973 | pmid = 4715291 | doi = 10.1210/jcem-37-1-148 }}</ref><ref name="pmid1379488">{{cite journal | author = Corbier P, Edwards DA, Roffi J | title = The neonatal testosterone surge: a comparative study | journal = Arch Int Physiol Biochim Biophys | volume = 100 | issue = 2 | pages = 127–31 | year = 1992 | pmid = 1379488 | doi = 10.3109/13813459209035274 }}</ref> The function of this rise in humans is unknown. It has been speculated that "brain ]" is occurring since no significant changes have been identified in other parts of the body.<ref name="pmid18445234">{{cite journal | author = Dakin CL, Wilson CA, Kalló I, Coen CW, Davies DC | title = Neonatal stimulation of 5-HT(2) receptors reduces androgen receptor expression in the rat anteroventral periventricular nucleus and sexually dimorphic preoptic area | journal = Eur. J. Neurosci. | volume = 27 | issue = 9 | pages = 2473–80 | date = May 2008 | pmid = 18445234 | doi = 10.1111/j.1460-9568.2008.06216.x }}</ref> It is interesting to note that the male brain is masculinized by the aromatization of testosterone into estrogen, which crosses the ] and enters the male brain, whereas female fetuses have ], which binds the estrogen so that female brains are not affected.<ref name="isbn0-495-60300-7">{{cite book | author = Kalat JW | title = Biological psychology | publisher = Wadsworth, Cengage Learning | location = Belmont, Calif | year = 2009 | pages = | isbn = 0-495-60300-7 | chapter = Reproductive behaviors | chapterurl =http://books.google.com/books?id=ZlSbk5rUY60C&lpg=PA321&ots=PUbcHTdh-A&pg=PA321#v=onepage&q&f=false | page = 321 }}</ref>
	=== Pre-peripubertal ===		===Low levels due to aging===
			{{Main|Late-onset hypogonadism#Management}}
	''Pre- Peripubertal effects'' are the first observable effects of rising
	androgen levels at the end of childhood, occurring in both boys and girls.
	*Adult-type ]
	*Increased oiliness of skin and hair, ]
	*] (appearance of ])
	*]
	*], accelerated ]
	*] on upper lip,on chin, and growth of ]s.
			Testosterone levels may decline gradually with age.<ref name="auto">{{cite book | chapter-url = https://www.ncbi.nlm.nih.gov/books/NBK216164/ | title = Testosterone and Aging: Clinical Research Directions. | chapter = Introduction | veditors = Liverman CT, Blazer DG, ((Institute of Medicine (US) Committee on Assessing the Need for Clinical Trials of Testosterone Replacement Therapy)) | date = January 1, 2004 | publisher = National Academies Press (US) | via = www.ncbi.nlm.nih.gov | isbn = 978-0-309-09063-6 | doi = 10.17226/10852 | pmid = 25009850 | access-date = November 11, 2016 | archive-date = January 10, 2016 | archive-url = https://web.archive.org/web/20160110170928/http://www.ncbi.nlm.nih.gov/books/NBK216164/ | url-status = live }}</ref><ref>{{cite journal | vauthors = Yeap BB, Almeida OP, Hyde Z, Norman PE, Chubb SA, Jamrozik K, Flicker L | title = In men older than 70 years, total testosterone remains stable while free testosterone declines with age. The Health in Men Study | journal = European Journal of Endocrinology| volume = 156 | issue = 5 | pages = 585–94 | date = May 2007 | pmid = 17468195 | doi = 10.1530/EJE-06-0714 | doi-access = free }}</ref> The United States ] (FDA) stated in 2015 that neither the benefits nor the safety of testosterone supplement have been established for low testosterone levels due to aging.<ref name=FDA2015/> The FDA has required that labels on testosterone include warnings about increased risk of heart attacks and stroke.<ref name=FDA2015/>
	=== Pubertal ===
	''Pubertal effects'' begin to occur when androgen has been higher than normal adult female levels for months or years. In males, these are usual late pubertal effects, and occur in women after prolonged periods of heightened levels of free testosterone in the blood.
	*Enlargement of ]. This might cause acne.
	*] enlargement or ]
	*Increased ] and frequency of ] or clitoral engorgement
	*Pubic hair extends to thighs and up toward ]
	*] (], ], ])
	* Loss of scalp hair (Androgenetic alopecia)
	*], periareolar hair, ] hair
	*]
	*]
	*Subcutaneous ] in face decreases
	*Increased muscle strength and mass<ref name="pmid8637535">{{cite journal | author = Bhasin S, Storer TW, Berman N, Callegari C, Clevenger B, Phillips J, Bunnell TJ, Tricker R, Shirazi A, Casaburi R | title = The effects of supraphysiologic doses of testosterone on muscle size and strength in normal men | journal = N. Engl. J. Med. | volume = 335 | issue = 1 | pages = 1–7 | date = July 1996 | pmid = 8637535 | doi = 10.1056/NEJM199607043350101 }}</ref>
	*Deepening of voice
	*Growth of the ]
	*Growth of ] tissue in testicles, male ]
	*Growth of ], brow, chin, nose, and remodeling of facial bone contours
	*Shoulders become broader and rib cage expands
	*Completion of bone maturation and termination of growth. This occurs indirectly via ] ] and hence more gradually in men than women.
	=== Adult ===		===Transgender men===
			{{Further|Transgender hormone therapy (female-to-male)}}
	Adult testosterone effects are more clearly demonstrable in males than in females, but are likely important to both sexes. Some of these effects may decline as testosterone levels decrease in the later decades of adult life.
			To take advantage of its ] effects, testosterone is administered to ] and other ] as part of ],<ref>{{cite web | url=http://www.nhs.uk/Conditions/Gender-dysphoria/Pages/Treatment.aspx | title=Gender dysphoria – Treatment | publisher=NHS Gov.uk | date=May 21, 2012 | access-date=October 31, 2013 | url-status=live | archive-url=https://web.archive.org/web/20131102135038/http://www.nhs.uk/Conditions/Gender-dysphoria/Pages/Treatment.aspx | archive-date=November 2, 2013}}</ref> titrated to clinical effect with a "target level" of the average male's testosterone level.<ref name="Medical Therapy and Health Maintenance for Transgender Men: A Guide For Health Care Providers">{{cite web | vauthors = Gorton RN, Buth J, Spade D | title = Medical Therapy and Health Maintenance for Transgender Men: A Guide For Health Care Providers | url = http://www.nickgorton.org/Medical%20Therapy%20and%20HM%20for%20Transgender%20Men_2005.pdf | publisher = Lyon-Martin Women's Health Services | access-date = December 11, 2016 | url-status = live | archive-url = https://web.archive.org/web/20161130005122/http://www.nickgorton.org/Medical%20Therapy%20and%20HM%20for%20Transgender%20Men_2005.pdf | archive-date = November 30, 2016}}</ref>
	], showing adult male testosterone levels in light blue at center-left.]]
			{{Medications and dosages used in hormone therapy for transgender men}}
	====Biological uses====
			{{clear}}
	* Testosterone is necessary for normal ] development. It activates genes in ]s, which promote differentiation of ].
	* Regulates acute HPA (]) response under dominance challenge<ref name="pmid18505319">{{cite journal | author = Mehta PH, Jones AC, Josephs RA | title = The social endocrinology of dominance: basal testosterone predicts cortisol changes and behavior following victory and defeat | journal = J Pers Soc Psychol | volume = 94 | issue = 6 | pages = 1078–93 | date = June 2008 | pmid = 18505319 | doi = 10.1037/0022-3514.94.6.1078 | url = http://homepage.psy.utexas.edu/homepage/faculty/josephs/pdf_documents/index.cfm.pdf }}</ref>
	* Regulator of cognitive and physical energy
	* Maintenance of muscle trophism
	* Testosterone regulates the population of ] receptors on ] and ] and hence platelet aggregation in humans<ref name="pmid15820970">{{cite journal | author = Ajayi AA, Halushka PV | title = Castration reduces platelet thromboxane A2 receptor density and aggregability | journal = QJM | volume = 98 | issue = 5 | pages = 349–56 | date = May 2005 | pmid = 15820970 | doi = 10.1093/qjmed/hci054 | url = }}</ref><ref name="pmid7758179">{{cite journal | author = Ajayi AA, Mathur R, Halushka PV | title = Testosterone increases human platelet thromboxane A2 receptor density and aggregation responses | journal = Circulation | volume = 91 | issue = 11 | pages = 2742–7 | date = June 1995 | pmid = 7758179 | doi = 10.1161/01.CIR.91.11.2742 }}</ref>
	* High androgen levels are associated with ] irregularities in both clinical populations and healthy women.<ref name="pmid17039468">{{cite journal | author = Van Anders SM, Watson NV | title = Menstrual cycle irregularities are associated with testosterone levels in healthy premenopausal women | journal = Am. J. Hum. Biol. | volume = 18 | issue = 6 | pages = 841–4 | year = 2006 | pmid = 17039468 | doi = 10.1002/ajhb.20555 }}</ref> See ].
			===Women===
	==== Cancer prevention and health risks ====
			Testosterone therapy is effective in the short-term for the treatment of ] (HSDD) in women.<ref name=Wie2014/> However, its long-term ] is unclear.<ref name=Wie2014>{{cite journal | vauthors = Wierman ME, Arlt W, Basson R, Davis SR, Miller KK, Murad MH, Rosner W, Santoro N | title = Androgen therapy in women: a reappraisal: an Endocrine Society clinical practice guideline | journal = The Journal of Clinical Endocrinology and Metabolism | volume = 99 | issue = 10 | pages = 3489–510 | date = Oct 2014 | pmid = 25279570 | doi = 10.1210/jc.2014-2260 | doi-access = free }}</ref> Because of a lack data to support its efficacy and safety, the ] recommends against the routine use of testosterone in women to treat ] due to ], ], ], high-dose ] therapy, or other causes.<ref name=Wie2014/> Similarly, because of a lack of data to support its efficacy and safety, the Endocrine Society recommends against the use of testosterone in women to improve general ], to treat ], ] due to causes other than HSDD, or to improve ], ], ], and/or ] health.<ref name=Wie2014/>
	* Testosterone does not cause deleterious effects in ]. In people who have undergone testosterone deprivation therapy, testosterone increases beyond the castrate level have been shown to increase the rate of spread of an existing prostate cancer.<ref name="pmid19011298">{{cite journal | author = Morgentaler A, Schulman C | title = Testosterone and prostate safety | journal = Front Horm Res | volume = 37 | issue = | pages = 197–203 | year = 2009 | pmid = 19011298 | doi = 10.1159/000176054 | url = | isbn = 978-3-8055-8622-1 | series = Frontiers of Hormone Research }}</ref><ref>{{cite journal | author = Rhoden EL, Averbeck MA, Teloken PE | title = Androgen replacement in men undergoing treatment for prostate cancer | journal = J Sex Med | volume = 5 | issue = 9 | pages = 2202–8 | year = 2008 | pmid = 18638000 | doi = 10.1111/j.1743-6109.2008.00925.x }}</ref><ref>{{cite journal | author = Morgentaler A, Traish AM | title = Shifting the paradigm of testosterone and prostate cancer: the saturation model and the limits of androgen-dependent growth | journal = Eur Urol | volume = 55 | issue = 2 | pages = 310–20 | year = 2009 | pmid = 18838208 | doi = 10.1016/j.eururo.2008.09.024 }}</ref>
	* Recent studies have shown conflicting results concerning the importance of ].<ref name="pmid17285783">{{cite journal | author = Haddad RM, Kennedy CC, Caples SM, Tracz MJ, Boloña ER, Sideras K, Uraga MV, Erwin PJ, Montori VM | title = Testosterone and cardiovascular risk in men: a systematic review and meta-analysis of randomized placebo-controlled trials | journal = Mayo Clin. Proc. | volume = 82 | issue = 1 | pages = 29–39 | date = January 2007 | pmid = 17285783 | doi = 10.4065/82.1.29 | url = }}</ref><ref name="pmid19464009">{{cite journal | author = Jones TH, Saad F | title = The effects of testosterone on risk factors for, and the mediators of, the atherosclerotic process | journal = Atherosclerosis | volume = 207 | issue = 2 | pages = 318–27 | date = April 2009 | pmid = 19464009 | doi = 10.1016/j.atherosclerosis.2009.04.016 | url = }}</ref> Nevertheless, maintaining normal testosterone levels in elderly men has been shown to improve many parameters that are thought to reduce cardiovascular disease risk, such as increased lean body mass, decreased visceral fat mass, decreased total cholesterol, and glycemic control.<ref name="pmid18488876">{{cite journal | author = Stanworth RD, Jones TH | title = Testosterone for the aging male; current evidence and recommended practice | journal = Clin Interv Aging | volume = 3 | issue = 1 | pages = 25–44 | year = 2008 | pmid = 18488876 | pmc = 2544367 | doi = | url = }}</ref>
	* Men whose testosterone levels are slightly above average are less likely to have high blood pressure, less likely to experience a heart attack, less likely to be obese, and less likely to rate their own health as fair or poor. However, high testosterone men are more likely to report one or more injuries, more likely to consume five or more alcoholic drinks in a day, more likely to have had a sexually transmitted infection, and more likely to smoke.<ref name="pmid10196726">{{cite journal | author = Booth A, Johnson DR, Granger DA | title = Testosterone and men's health | journal = J Behav Med | volume = 22 | issue = 1 | pages = 1–19 | date = February 1999 | pmid = 10196726 | doi = 10.1023/A:1018705001117 | laysource = CNN | layurl = http://articles.cnn.com/1999-12-03/health/testosterone.wmd_1_testosterone-nanograms-risky-behavior?_s=PM:HEALTH }}</ref>
			A 2014 systematic review and meta-analysis of 35 studies consisting of over 5,000 ] women with normal ] function found that testosterone therapy was associated with significant improvement in a variety of domains of sexual function.<ref name="pmid25279572">{{cite journal | vauthors = Elraiyah T, Sonbol MB, Wang Z, Khairalseed T, Asi N, Undavalli C, Nabhan M, Firwana B, Altayar O, Prokop L, Montori VM, Murad MH | title = Clinical review: The benefits and harms of systemic testosterone therapy in postmenopausal women with normal adrenal function: a systematic review and meta-analysis | journal = J. Clin. Endocrinol. Metab. | volume = 99 | issue = 10 | pages = 3543–50 | year = 2014 | pmid = 25279572 | pmc = 5393495 | doi = 10.1210/jc.2014-2262 }}</ref> These domains included frequency of ], ], ], and sexual satisfaction, among others.<ref name="pmid25279572" /> Women who were menopausal due to ] showed significantly greater improvement in sexual function with testosterone relative to those who had normal menopause.<ref name="pmid25279572" /> In addition to beneficial effects on sexual function, testosterone was associated with unfavorable changes in ].<ref name="pmid25279572" /> These included decreased levels of total ], ]s, and ] (HDL) cholesterol, and increased levels of ] (LDL) cholesterol.<ref name="pmid25279572" /> However, the changes were small in magnitude, and the long-term significance in relation to ] outcomes is uncertain.<ref name="pmid25279572" /> The changes were more pronounced with oral ] than with ] routes, such as ] testosterone.<ref name="pmid25279572" /> Testosterone showed no significant effect on ] ] ], ] (BMD), or ]s like ] or ].<ref name="pmid25279572" /> Conversely, it was associated with a significant incidence of androgenic side effects, including ] and ] (excessive facial/body hair growth).<ref name="pmid25279572" /> Other androgenic side effects, such as ], ], and ], were also reported in some trials, but were excluded from analyses due to insufficient data.<ref name="pmid25279572" /> The overall quality of the evidence was rated as low and was considered to be inconclusive in certain areas, for instance on long-term safety.<ref name="pmid25279572" />
	==== Romantic relationships and fatherhood ====
	Falling in love decreases men's testosterone levels while increasing women's testosterone levels. There has been speculation that these changes in testosterone result in the temporary reduction of differences in behavior between the sexes.<ref name="pmid15177709">{{cite journal | author = Marazziti D, Canale D | title = Hormonal changes when falling in love | journal = Psychoneuroendocrinology | volume = 29 | issue = 7 | pages = 931–6 | date = August 2004 | pmid = 15177709 | doi = 10.1016/j.psyneuen.2003.08.006 }}</ref> However, it is suggested that after the "honeymoon phase" ends—about one to three years into a relationship—this change in testosterone levels is no longer apparent.<ref name="pmid15177709" /> Fatherhood also decreases testosterone levels in men, suggesting that the resulting emotional and behavioral changes promote paternal care.<ref>{{cite journal | author = Berg SJ, Wynne-Edwards KE | title = Changes in testosterone, cortisol, and estradiol levels in men becoming fathers | journal = Mayo Clinic Proceedings | volume = 76 | issue = 1 | pages = 582–592 | year = 2001 | pmid = 11393496 | doi = 10.4065/76.6.582 | url = }}</ref> Men who produce less testosterone are more likely to be in a relationship<ref name="pmid16621328">{{cite journal | author = van Anders SM, Watson NV | title = Relationship status and testosterone in North American heterosexual and non-heterosexual men and women: cross-sectional and longitudinal data | journal = Psychoneuroendocrinology | volume = 31 | issue = 6 | pages = 715–23 | date = July 2006 | pmid = 16621328 | doi = 10.1016/j.psyneuen.2006.01.008 }}</ref> and/or married,<ref name = "Booth_Dabbs_1993"/> and men who produce more testosterone are more likely to divorce;<ref name = "Booth_Dabbs_1993">{{cite journal | author = Booth A, Dabbs JM|title=Testosterone and Men's Marriages | journal = Social Forces | year = 1993 | volume = 72 | issue = 2 | pages = 463–477 | doi = 10.1093/sf/72.2.463}}</ref> however, causality cannot be determined in this relationship. Marriage or commitment could cause a decrease in testosterone levels.<ref name=Mazur_Michalek_1998>{{cite journal | author = Mazur A, Michalek J | title = Marriage, Divorce, and Male Testosterone | journal = Social Forces | year = 1998 | volume = 77 | issue = 1 | pages = 315–330 | doi = 10.1093/sf/77.1.315 }}</ref> Single men who have not had relationship experience have lower testosterone levels than single men with experience. It is suggested that these single men with prior experience are in a more competitive state than their non-experienced counterparts.<ref name=Gray_2004>{{cite journal | author = Gray PB, Chapman JF, Burnham TC, McIntyre MH, Lipson SF, Ellison PT | title = Human male pair bonding and testosterone | journal = Human Nature | year = 2004 | volume = 15 | issue = 2 | pages = 119–131 | doi = 10.1007/s12110-004-1016-6 }}</ref> Married men who engage in bond-maintenance activities such as spending the day with their spouse/and or child have no different testosterone levels compared to times when they do not engage in such activities. Collectively, these results suggest that the presence of competitive activities rather than bond-maintenance activities are more relevant to changes in testosterone levels.<ref name="pmid15219639">{{cite journal | author = Gray PB, Campbell BC, Marlowe FW, Lipson SF, Ellison PT | title = Social variables predict between-subject but not day-to-day variation in the testosterone of US men | journal = Psychoneuroendocrinology | volume = 29 | issue = 9 | pages = 1153–62 | date = October 2004 | pmid = 15219639 | doi = 10.1016/j.psyneuen.2004.01.008 }}</ref>
			A subsequent 2017 systematic review and meta-analysis of studies including over 3,000 postmenopausal women with HSDD similarly found that short-term transdermal testosterone therapy was effective in improving multiple domains of sexual function.<ref name="pmid27916205">{{cite journal | vauthors = Achilli C, Pundir J, Ramanathan P, Sabatini L, Hamoda H, Panay N | title = Efficacy and safety of transdermal testosterone in postmenopausal women with hypoactive sexual desire disorder: a systematic review and meta-analysis | journal = Fertil. Steril. | volume = 107 | issue = 2 | pages = 475–482.e15 | year = 2017 | pmid = 27916205 | doi = 10.1016/j.fertnstert.2016.10.028 | doi-access = free }}</ref> Androgenic adverse effects such as acne and hirsutism were significantly greater in incidence with testosterone therapy, whereas no significant differences in "increase in facial hair, alopecia, voice deepening, urinary symptoms, breast pain, headache, site reaction to the patch, total adverse events, serious adverse events, reasons for withdrawal from the study, and the number of women who completed the study" were seen relative to controls.<ref name="pmid27916205" />
	Men who produce more testosterone are more likely to engage in extramarital sex.<ref name=Booth_Dabbs_1993/> Testosterone levels do not rely on physical presence of a partner for men engaging in relationships (same-city vs. long-distance), men have similar testosterone levels across the board.<ref name="pmid16621328" /> Physical presence may be required for women who are in relationships for the testosterone–partner interaction, where same-city partnered women have lower testosterone levels than long-distance partnered women.<ref name="pmid17196592">{{cite journal | author = van Anders SM, Watson NV | title = Testosterone levels in women and men who are single, in long-distance relationships, or same-city relationships | journal = Horm Behav | volume = 51 | issue = 2 | pages = 286–91 | date = February 2007 | pmid = 17196592 | doi = 10.1016/j.yhbeh.2006.11.005 }}</ref>
			Although testosterone has been found to be effective at improving sexual function in postmenopausal women, the doses employed have been supraphysiological.<ref name="pmid26589379">{{cite journal | vauthors = Cappelletti M, Wallen K | title = Increasing women's sexual desire: The comparative effectiveness of estrogens and androgens | journal = Horm Behav | volume = 78 | pages = 178–93 | date = February 2016 | pmid = 26589379 | pmc = 4720522 | doi = 10.1016/j.yhbeh.2015.11.003 }}</ref><ref name="pmid27785108">{{cite journal | vauthors = Reed BG, Bou Nemer L, Carr BR | title = Has testosterone passed the test in premenopausal women with low libido? A systematic review | journal = Int J Women's Health | volume = 8 | pages = 599–607 | year = 2016 | pmid = 27785108 | pmc = 5066846 | doi = 10.2147/IJWH.S116212 | doi-access = free }}</ref> In contrast to these high doses, there is little support for the notion that testosterone is a critical hormone for sexual desire and function in women under normal physiological circumstances.<ref name="pmid26589379" /><ref name="pmid27785108" /> Low doses of testosterone resulting in physiological levels of testosterone (<50&nbsp;ng/dL) have not been found to significantly increase sexual desire or function in women in most studies.<ref name="pmid26589379" /> Similarly, there appears to be little or no relationship between total or free testosterone levels in the normal physiological range and sexual desire in premenopausal women.<ref name="pmid27785108" /><ref name="pmid26589379" /> Only high doses of testosterone resulting in supraphysiological levels of testosterone (>50&nbsp;ng/dL) significantly increase sexual desire in women, with levels of testosterone of 80 to 150&nbsp;ng/dL "slightly" increasing sex drive.<ref name="pmid26589379" /><ref name="pmid27785108" /> In accordance, men experience ] at testosterone levels of below 300&nbsp;ng/dL, and men that have levels of testosterone of approximately 200&nbsp;ng/dL frequently experience such problems.<ref name="pmid27785108" /> The high doses of testosterone required to increase sexual desire in women may have a significant risk of masculinization with long-term therapy.<ref name="pmid27785108" /><ref name="pmid26589379" /> For this reason, and due to the unknown health effects and safety of testosterone therapy, its use may be inappropriate.<ref name="pmid27785108" /><ref name="pmid26589379" /> In 2003, the FDA rejected Intrinsa, a 300&nbsp;μg/day ] for the treatment of sexual dysfunction in postmenopausal women.<ref name="pmid26589379" /><ref name="pmid27785108" /> The reasons cited were limited efficacy (about one additional sexually satisfying event per month), concerns about safety and potential adverse effects with long-term therapy, and concerns about inappropriate ].<ref name="pmid26589379" /><ref name="pmid27785108" /> It appears that in women, rather than testosterone, ] may be the most important hormone involved in sexual desire, although data on the clinical use of ] to increase sexual desire in women is limited.<ref name="pmid26589379" /><ref name="pmid26944462">{{cite journal | vauthors = Santoro N, Worsley R, Miller KK, Parish SJ, Davis SR | title = Role of Estrogens and Estrogen-Like Compounds in Female Sexual Function and Dysfunction | journal = J Sex Med | volume = 13 | issue = 3 | pages = 305–16 | date = March 2016 | pmid = 26944462 | doi = 10.1016/j.jsxm.2015.11.015 }}</ref><ref name="pmid28895561">{{cite journal | vauthors = Stone L | s2cid = 7140458 | title = Sexual medicine: Transdermal oestrogen is effective | journal = Nat Rev Urol | volume = 14 | issue = 11 | pages = 638 | date = November 2017 | pmid = 28895561 | doi = 10.1038/nrurol.2017.152 | doi-access = free }}</ref>
	==== Testosterone and sexual arousal ====
	{{See also|Hormones and sexual arousal}}
	It has been found that when testosterone and endorphins in ejaculated semen meet the cervical wall after sexual intercourse, females receive a spike in testosterone, endorphin, and ] levels, and males after orgasm during copulation experience an increase in endorphins and a marked increase in oxytocin levels. This adds to the hospitable physiological environment in the female internal reproductive tract for conceiving, and later for nurturing the conceptus in the pre-embryonic stages, and stimulates feelings of love, desire, and paternal care in the male (this is the only time male oxytocin levels rival a female's).<ref name="pmid15177709" />
			There are no testosterone products approved for use in women in the United States and many other countries.<ref name="PalSayegh2017">{{cite book|vauthors=Pal L, Sayegh RA|title=Essentials of Menopause Management: A Case-Based Approach|url=https://books.google.com/books?id=HVkLDgAAQBAJ&pg=PA180|date=January 21, 2017|publisher=Springer|isbn=978-3-319-42451-4|pages=180–|access-date=July 31, 2018|archive-date=April 14, 2019|archive-url=https://web.archive.org/web/20190414214953/https://books.google.com/books?id=HVkLDgAAQBAJ&pg=PA180|url-status=live}}</ref> There are approved testosterone products for women in Australia, where it is considered a drug of dependence, medicines that are subject to misuse and trafficking, <ref>{{cite web | title = Drugs of dependence and drug-dependent persons | url = http://www.health.vic.gov.au/drugs-and-poisons/drugs-of-dependence-and-drug-dependent-persons | work= Department of Health | publisher = Victorian Government | access-date = May 24, 2022 | archive-date = March 8, 2022 | archive-url = https://web.archive.org/web/20220308145610/https://www.health.vic.gov.au/drugs-and-poisons/drugs-of-dependence-and-drug-dependent-persons | url-status = live }}</ref> and some European countries.<ref name="PalSayegh2017" /> Testosterone pellet implants are approved for use in postmenopausal women in the United Kingdom.<ref name="LoboKelsey2000">{{cite book|vauthors=Lobo RA, Kelsey J, Marcus R|title=Menopause: Biology and Pathobiology|url=https://books.google.com/books?id=i9HXKhjvNVAC&pg=PA454|date=May 22, 2000|publisher=Academic Press|isbn=978-0-08-053620-0|pages=454–|access-date=September 27, 2018|archive-date=April 14, 2019|archive-url=https://web.archive.org/web/20190414215015/https://books.google.com/books?id=i9HXKhjvNVAC&pg=PA454|url-status=live}}</ref><ref name="BagatellBremner2003">{{cite book|vauthors=Bagatell C, Bremner WJ|title=Androgens in Health and Disease|url=https://books.google.com/books?id=vDcBCAAAQBAJ&pg=PA374|date=May 27, 2003|publisher=Springer Science & Business Media|isbn=978-1-59259-388-0|pages=374–|access-date=September 27, 2018|archive-date=December 20, 2019|archive-url=https://web.archive.org/web/20191220150236/https://books.google.com/books?id=vDcBCAAAQBAJ&pg=PA374|url-status=live}}</ref> Testosterone products for men can be used ] in women in the United States.<ref name="PalSayegh2017" /> Alternatively, testosterone products for women are available from ] in the United States, although such products are unregulated and manufacturing quality is not ensured.<ref name="pmid28509626">{{cite journal | vauthors = L'Hermite M | s2cid = 26079596 | title = Custom-compounded bioidentical hormone therapy: why so popular despite potential harm? The case against routine use | journal = Climacteric | volume = 20 | issue = 3 | pages = 205–211 | date = June 2017 | pmid = 28509626 | doi = 10.1080/13697137.2017.1285277 }}</ref>
	Testosterone levels follow a nyctohemeral rhythm that peaks early each day, regardless of sexual activity.<ref name="pmid5061159">{{cite journal | author = Fox CA, Ismail AA, Love DN, Kirkham KE, Loraine JA | title = Studies on the relationship between plasma testosterone levels and human sexual activity | journal = J. Endocrinol. | volume = 52 | issue = 1 | pages = 51–8 | date = January 1972 | pmid = 5061159 | doi = 10.1677/joe.0.0520051 }}</ref>
			{{Androgen replacement therapy formulations and dosages used in women}}
	There are positive correlations between positive orgasm experience in women and testosterone levels where relaxation was a key perception of the experience. There is no correlation between testosterone and men's perceptions of their orgasm experience, and also no correlation between higher testosterone levels and greater sexual assertiveness in either sex.<ref name="pmid19409392">{{cite journal | author = van Anders SM, Dunn EJ | title = Are gonadal steroids linked with orgasm perceptions and sexual assertiveness in women and men? | journal = Horm Behav | volume = 56 | issue = 2 | pages = 206–13 | date = August 2009 | pmid = 19409392 | doi = 10.1016/j.yhbeh.2009.04.007 }}</ref>
			{{Androgen/anabolic steroid dosages for breast cancer}}
	An increase in testosterone levels has also been found to occur in both men and women who have masturbation-induced orgasms.<ref name="pmid10367606">{{cite journal | author = Exton MS, Bindert A, Krüger T, Scheller F, Hartmann U, Schedlowski M | title = Cardiovascular and endocrine alterations after masturbation-induced orgasm in women | journal = Psychosom Med | volume = 61 | issue = 3 | pages = 280–9 | year = 1999 | pmid = 10367606 | doi = 10.1097/00006842-199905000-00005 }}</ref><ref name="pmid135817">{{cite journal | author = Purvis K, Landgren BM, Cekan Z, Diczfalusy E | title = Endocrine effects of masturbation in men | journal = J. Endocrinol. | volume = 70 | issue = 3 | pages = 439–44 | date = September 1976 | pmid = 135817 | doi = 10.1677/joe.0.0700439 }}</ref>
	=====Mammalian studies=====		===Available forms===
			]
	Studies conducted on rats have indicated that their degree of sexual arousal is sensitive to reductions in testosterone. When testosterone-deprived rats were given medium levels of testosterone, their sexual behaviors (copulation, partner preference, etc.) resumed, but not when given low amounts of the same hormone. Therefore, these mammals may provide a model for studying clinical populations among humans suffering from sexual arousal deficits such as ].<ref name="pmid20920505">{{cite journal | author = Harding SM, Velotta JP | title = Comparing the relative amount of testosterone required to restore sexual arousal, motivation, and performance in male rats | journal = Horm Behav | volume = 59 | issue = 5 | pages = 666–73 | date = May 2011 | pmid = 20920505 | doi = 10.1016/j.yhbeh.2010.09.009 }}</ref>
			Testosterone has been marketed for use by ], ], ], ], ] (]), ] (]s), ] (]), and ] (]) ].<ref name="NieschlagBehre2012b">{{cite book|vauthors=Nieschlag E, Behre MH|title=Testosterone: Action - Deficiency - Substitution|url=https://books.google.com/books?id=jn3nCAAAQBAJ&pg=PA350|date=December 6, 2012|publisher=Springer Science & Business Media|isbn=978-3-642-72185-4|pages=1–,9,298,309–331,349–353,366–367|access-date=November 18, 2016 |archive-date=April 14, 2019|archive-url=https://web.archive.org/web/20190414215012/https://books.google.com/books?id=jn3nCAAAQBAJ&pg=PA350|url-status=live}}</ref><ref name="Melmed2016"/><!--Defined in Template:Available forms of testosterone--><ref name="Llewellyn2011" /><ref name="Brotherton1976"/><!--Defined in Template:Available forms of testosterone--> It is provided unmodified and as a ] such as ], ], ], or ], which act as ]s of testosterone.<ref name="NieschlagBehre2012b" /><ref name="Melmed2016" /><ref name="Llewellyn2011" /> The most common ] for testosterone is by intramuscular injection.<ref name="NieschlagBehre2012b" /> However, it has been reported that AndroGel, a transdermal gel formulation of testosterone, has become the most popular form of testosterone in androgen replacement therapy for hypogonadism in the United States.<ref name="Melmed2016" />
			{{Available forms of testosterone}}
	In one study, almost every mammalian species examined demonstrated a marked increase in a male's testosterone level upon encountering a ''novel'' female. P.J. James et al. investigated the role of genotype on such so-called reflexive testosterone increases in male mice. They also concluded that this response is related to the male's initial level of sexual arousal.<ref name="pmid16828762">{{cite journal | author = James PJ, Nyby JG, Saviolakis GA | title = Sexually stimulated testosterone release in male mice (Mus musculus): roles of genotype and sexual arousal | journal = Horm Behav | volume = 50 | issue = 3 | pages = 424–31 | date = September 2006 | pmid = 16828762 | doi = 10.1016/j.yhbeh.2006.05.004 }}</ref>
			==Non-medical use==
	In non-human primates it has been suggested that testosterone in puberty stimulates ], which allows the primate to increasingly seek out sexual experiences with females and thus creates a sexual preference for females.<ref name="pmid11534996">{{cite journal | author = Wallen K | title = Sex and context: hormones and primate sexual motivation | journal = Horm Behav | volume = 40 | issue = 2 | pages = 339–57 | date = September 2001 | pmid = 11534996 | doi = 10.1006/hbeh.2001.1696 }}</ref> Some research has also indicated that if testosterone is eliminated in an adult male human or other adult male primate's system, its ''sexual motivation'' decreases, but there is no corresponding decrease in ''ability'' to engage in sexual activity (mounting, ejaculating, etc.).<ref name="pmid11534996"/>
			===Athletics===
	===== Male sexual arousal =====
			{{See also|Ergogenic use of anabolic steroids|Anabolic–androgenic steroids abuse}}
	Higher levels of testosterone were associated with periods of sexual activity within subjects, but between subjects testosterone levels were higher for less sexually active individuals.<ref name="pmid1275688">{{cite journal | author = Kraemer HC, Becker HB, Brodie HK, Doering CH, Moos RH, Hamburg DA | title = Orgasmic frequency and plasma testosterone levels in normal human males | journal = Arch Sex Behav | volume = 5 | issue = 2 | pages = 125–32 | date = March 1976 | pmid = 1275688 | doi = 10.1007/BF01541869 | url = }}</ref> Men who have sexual encounters with unfamiliar or multiple partners experience large increases of testosterone the morning after, which helps the man go about his way, as if they haven't done anything wrong and helps them to not be emotional, in an attempt to ignore the fact that they had such intimate relations with only a stranger.<ref name="pmid12367570">{{cite journal | author = Hirschenhauser K, Frigerio D, Grammer K, Magnusson MS | title = Monthly patterns of testosterone and behavior in prospective fathers | journal = Horm Behav | volume = 42 | issue = 2 | pages = 172–81 | date = September 2002 | pmid = 12367570 | doi = 10.1006/hbeh.2002.1815 }}</ref>
			Testosterone is used as a form of ] among ]s in order to improve performance.<ref name=":1">{{Cite web|url=http://list.wada-ama.org/list/s1-anabolic-agents|title=S1. Anabolic Agents {{!}} List of Prohibited Substances and Methods|website=list.wada-ama.org|access-date=June 6, 2016|url-status=dead|archive-url=https://web.archive.org/web/20160527144701/http://list.wada-ama.org/list/s1-anabolic-agents/|archive-date=May 27, 2016}}</ref> Testosterone is classified as an ] agent and is on the ] (WADA) List of Prohibited Substances and Methods.<ref name=":1" /> Hormone supplements cause the endocrine system to adjust its production and lower the natural production of the hormone, so when supplements are discontinued, natural hormone production is lower than it was originally.{{citation needed|date=November 2016}}
	Men who watch a sexually explicit movie have an average increase of 35% in testosterone, peaking at 60–90 minutes after the end of the film, but no increase is seen in men who watch sexually neutral films.<ref>{{cite journal | author = Pirke KM, Kockott G, Dittmar F | title = Psychosexual stimulation and plasma testosterone in man | journal = Arch Sex Behav | volume = 3 | issue = 6 | pages = 577–84 | date = November 1974 | pmid = 4429441 | doi = 10.1007/BF01541140 }}</ref> Men who watch sexually explicit films also report increased motivation, competitiveness, and decreased exhaustion.<ref name="pmid4001279">{{cite journal | author = Hellhammer DH, Hubert W, Schürmeyer T | title = Changes in saliva testosterone after psychological stimulation in men | journal = Psychoneuroendocrinology | volume = 10 | issue = 1 | pages = 77–81 | year = 1985 | pmid = 4001279 | doi = 10.1016/0306-4530(85)90041-1 }}</ref> Previous research has found a link between relaxation following sexual arousal and testosterone levels, though ejaculation is not recommend.<ref name="pmid3602262">{{cite journal | author = Rowland DL, Heiman JR, Gladue BA, Hatch JP, Doering CH, Weiler SJ | title = Endocrine, psychological and genital response to sexual arousal in men | journal = Psychoneuroendocrinology | volume = 12 | issue = 2 | pages = 149–58 | year = 1987 | pmid = 3602262 | doi = 10.1016/0306-4530(87)90045-X }}</ref>
			]s (AAS), including testosterone and its esters, have also been taken to enhance muscle development, strength, or endurance. They do so directly by increasing the muscles' protein synthesis. As a result, muscle fibers become larger and repair faster than the average person's.{{citation needed|date=November 2016}}
	A 2002 study found that testosterone increased in heterosexual men after having had a brief conversation with a woman. The increase in testosterone levels was associated with the degree that the women thought the men were trying to impress them.<ref name=Roney_2003>{{cite journal | author = Roney JR, Mahler SV, Maestripieri D | title = Behavioral and hormonal responses of men to brief interactions with women | journal = Evolution and Human Behavior | year = 2003 | volume = 24 | issue = 6 | pages = 365–375 | doi = 10.1016/S1090-5138(03)00053-9 }}</ref>
			After a series of scandals and publicity in the 1980s (such as ] improved performance at the ]), ]s of AAS use were renewed or strengthened by many sports organizations. Testosterone and other AAS were designated a "]" by the ] in 1990, with the ''Anabolic Steroid Control Act''.<ref>{{cite web| title=Anabolic Steroid Control Act| url=http://www.ussc.gov/USSCsteroidsreport-0306.pdf#search=%22Anabolic%20Steroid%20Control%20Act%20of%201990%22| publisher=United States Sentencing Commission| year=1990| access-date=November 11, 2016| url-status=dead| archive-date=August 30, 2016| archive-url=https://web.archive.org/web/20160830201115/http://www.ussc.gov/USSCsteroidsreport-0306.pdf#search=%22Anabolic%20Steroid%20Control%20Act%20of%201990%22}}</ref> Their use is seen as an issue in modern sport, particularly given the lengths to which athletes and professional laboratories go to in trying to conceal such use from sports regulators. Steroid use once again came into the spotlight as a result of Canadian ] ]'s double murder-suicide in 2007; however, there is no evidence implicating steroid use as a factor in the incident.{{citation needed|date=February 2014}}
	Men's levels of testosterone, a hormone known to affect men's mating behaviour, changes depending on whether they are exposed to an ovulating or nonovulating woman's body odour. Men who are exposed to scents of ovulating women maintained a stable testosterone level that was higher than the testosterone level of men exposed to nonovulation cues. Testosterone levels and sexual arousal in men are heavily aware of hormone cycles in females.<ref name="pmid20424057">{{cite journal | author = Miller SL, Maner JK | title = Scent of a woman: men's testosterone responses to olfactory ovulation cues | journal = Psychol Sci | volume = 21 | issue = 2 | pages = 276–83 | date = February 2010 | pmid = 20424057 | doi = 10.1177/0956797609357733 }}</ref> This may be linked to the ''ovulatory shift hypothesis'',<ref name = "Gangestead_2005">{{cite journal | author = Gangestead SW, Thornhill R, Garver-Apgar CE | title = Adaptations to Ovulation: Implications for Sexual and Social Behavior | journal = Current Directions in Psychological Science | volume = 14 | issue = 6 | pages = 312–316 | year = 2005 | doi = 10.1111/j.0963-7214.2005.00388.x }}</ref> where males are adapted to respond to the ovulation cycles of females by sensing when they are most fertile and whereby females look for preferred male mates when they are the most fertile; both actions may be driven by hormones.
			Some female athletes may have naturally higher levels of testosterone than others, and may be asked to consent to ] and either surgery or drugs to decrease testosterone levels.<ref name="NYT-20140411">{{cite news | vauthors = Karkazis K, Jordan-Young R | title = The Trouble With Too Much T | url = https://www.nytimes.com/2014/04/11/opinion/the-trouble-with-too-much-t.html | date = April 11, 2014 | work=] | access-date = April 12, 2014 | archive-url = https://web.archive.org/web/20140412011234/http://www.nytimes.com/2014/04/11/opinion/the-trouble-with-too-much-t.html | archive-date = April 12, 2014 | url-status = live}}</ref> This has proven contentious, with the ] suspending the IAAF policy due to insufficient evidence of a link between high androgen levels and improved athletic performance.<ref>{{cite web| vauthors = Fagan K | author-link = Kate Fagan (sportswriter) | title = Katie Ledecky is crushing records, so why are we still worried about Caster Semenya?| work= ]| access-date = August 27, 2016| date = August 13, 2016| url = http://www.espn.com/espnw/voices/article/17275159/| url-status = live| archive-url = https://web.archive.org/web/20160818073128/http://www.espn.com/espnw/voices/article/17275159/| archive-date = August 18, 2016}}</ref><ref>{{Cite news| issn = 0362-4331| vauthors = Padawer R | title = The Humiliating Practice of Sex-Testing Female Athletes| work= ]| access-date = August 27, 2016| date = June 28, 2016| url = https://www.nytimes.com/2016/07/03/magazine/the-humiliating-practice-of-sex-testing-female-athletes.html| url-status = live| archive-url = https://web.archive.org/web/20160628124045/http://www.nytimes.com/2016/07/03/magazine/the-humiliating-practice-of-sex-testing-female-athletes.html| archive-date = June 28, 2016}}</ref>
	In a 1991 study, males were exposed to either visual or auditory erotic stimuli and asked to complete a cognitive task, where the number of errors on the task indicated how distracted the participant was by the stimuli. It concluded that men with lower thresholds for sexual arousal have a greater likelihood to attend to sexual information and that testosterone may have an impact by enhancing their attention to the relevant stimuli.<ref name="pmid1937428">{{cite journal | author = Alexander GM, Sherwin BB | title = The association between testosterone, sexual arousal, and selective attention for erotic stimuli in men | journal = Horm Behav | volume = 25 | issue = 3 | pages = 367–81 | date = September 1991 | pmid = 1937428 | doi = 10.1016/0018-506X(91)90008-6 }}</ref>
			====Detection of abuse====
	] theory: Testosterone levels are shown to increase as a response to previously neutral stimuli when conditioned to become sexual in male rats.<ref name="pmid6665072">{{cite journal | author = Hart BL | title = Role of testosterone secretion and penile reflexes in sexual behavior and sperm competition in male rats: a theoretical contribution | journal = Physiol. Behav. | volume = 31 | issue = 6 | pages = 823–7 | date = December 1983 | pmid = 6665072 | doi = 10.1016/0031-9384(83)90279-2 }}</ref> This reaction engages penile reflexes (such as erection and ejaculation) that aid in sperm competition when more than one male is present in mating encounters, allowing for more production of successful sperm and a higher chance of reproduction.
			A number of methods for detecting testosterone use by athletes have been employed, most based on a ]. These include the testosterone/] ratio (normally less than 6), the testosterone/luteinizing hormone ratio and the ]/] ratio (pharmaceutical testosterone contains less carbon-13 than endogenous testosterone). In some testing programs, an individual's own historical results may serve as a reference interval for interpretation of a suspicious finding. Another approach being investigated is the detection of the administered form of testosterone, usually an ester, in hair.<ref name="pmid19549614">{{cite journal | vauthors = Strahm E, Emery C, Saugy M, Dvorak J, Saudan C | title = Detection of testosterone administration based on the carbon isotope ratio profiling of endogenous steroids: international reference populations of professional soccer players | journal = British Journal of Sports Medicine | volume = 43 | issue = 13 | pages = 1041–44 | date = Dec 2009 | pmid = 19549614 | pmc = 2784500 | doi = 10.1136/bjsm.2009.058669 }}</ref><ref name="pmid20355155">{{cite journal | vauthors = Kicman AT, Cowan DA | title = Subject-based profiling for the detection of testosterone administration in sport | journal = Drug Testing and Analysis | volume = 1 | issue = 1 | pages = 22–4 | date = Jan 2009 | pmid = 20355155 | doi = 10.1002/dta.14 | doi-access = free }}</ref><ref name="pmid19353724">{{cite journal | vauthors = Pozo OJ, Deventer K, Van Eenoo P, Rubens R, Delbeke FT | title = Quantification of testosterone undecanoate in human hair by liquid chromatography-tandem mass spectrometry | journal = Biomedical Chromatography | volume = 23 | issue = 8 | pages = 873–80 | date = Aug 2009 | pmid = 19353724 | doi = 10.1002/bmc.1199 }}</ref><ref name="isbn0-9626523-6-9">{{cite book | vauthors = Baselt RC | title = Disposition of Toxic Drugs & Chemicals in Man | edition = 8th | publisher = Biomedical Publications | location = Foster City, Calif | year = 2008 | pages = 1501–04 | isbn = 978-0-9626523-7-0 }}</ref>
			==Contraindications==
	===== Female sexual arousal =====
			Absolute ]s of testosterone include ], ] (>54%), uncontrolled ], various other ]s, and uncontrolled ].<ref name="KavoussiCostabile2012">{{cite book |veditors=Kavoussi P, Costabile RA, Salonia A|title=Clinical Urologic Endocrinology: Principles for Men's Health|url=https://books.google.com/books?id=Eko5nLSINv8C&pg=PA65|date=October 19, 2012|publisher=Springer Science & Business Media|isbn=978-1-4471-4405-2|pages=65–|access-date=November 13, 2016|archive-date=April 14, 2019|archive-url=https://web.archive.org/web/20190414215026/https://books.google.com/books?id=Eko5nLSINv8C&pg=PA65|url-status=live}}</ref> ] is said by some sources to be an absolute contraindication of testosterone therapy,<ref name="KavoussiCostabile2012" /> but androgens including testosterone have also actually been used to treat breast cancer.<ref name="Perry2008">{{cite book| vauthors = Perry MC |title=The Chemotherapy Source Book |url=https://books.google.com/books?id=CDADMzS0TKUC&pg=PA368|year=2008|publisher=Lippincott Williams & Wilkins|isbn=978-0-7817-7328-7 |pages=368–|archive-url=https://web.archive.org/web/20170908214106/https://books.google.com/books?id=CDADMzS0TKUC&pg=PA368|archive-date=September 8, 2017|url-status=live}}</ref> Relative contraindications of testosterone include elevated ] (PSA) in men with a high risk of prostate cancer due to ] or family history, severe ]s, and elevated hematocrit (>50%).<ref name="KavoussiCostabile2012" />
	Androgens may modulate the physiology of vaginal tissue and contribute to female genital sexual arousal.<ref name="pmid12007897">{{cite journal | author = Traish AM, Kim N, Min K, Munarriz R, Goldstein I | title = Role of androgens in female genital sexual arousal: receptor expression, structure, and function | journal = Fertil. Steril. | volume = 77 Suppl 4 | issue = | pages = S11–8 | date = April 2002 | pmid = 12007897 | doi = 10.1016/s0015-0282(02)02978-3 }}</ref> Women's level of testosterone is higher when measured pre-intercourse vs pre-cuddling, as well as post-intercourse vs post-cuddling.<ref name="pmid17320881">{{cite journal | author = van Anders SM, Hamilton LD, Schmidt N, Watson NV | title = Associations between testosterone secretion and sexual activity in women | journal = Horm Behav | volume = 51 | issue = 4 | pages = 477–82 | date = April 2007 | pmid = 17320881 | doi = 10.1016/j.yhbeh.2007.01.003 }}</ref> There is a time lag effect when testosterone is administered, on genital arousal in women. In addition, a continuous increase in vaginal sexual arousal may result in higher genital sensations and sexual appetitive behaviors.<ref name="pmid10665617">{{cite journal | author = Tuiten A, Van Honk J, Koppeschaar H, Bernaards C, Thijssen J, Verbaten R | title = Time course of effects of testosterone administration on sexual arousal in women | journal = Arch. Gen. Psychiatry | volume = 57 | issue = 2 | pages = 149–53; discussion 155–6 | date = February 2000 | pmid = 10665617 | doi = 10.1001/archpsyc.57.2.149 }}</ref>
			==Side effects==
	When females have a higher baseline level of testosterone, they have higher increases in sexual arousal levels but smaller increases in testosterone, indicating a ceiling effect on testosterone levels in females. Sexual thoughts also change the level of testosterone but not level of cortisol in the female body, and hormonal contraceptives may have an impact on the variation in testosterone response to sexual thoughts.<ref name="pmid21185838">{{cite journal | author = Goldey KL, van Anders SM | title = Sexy thoughts: effects of sexual cognitions on testosterone, cortisol, and arousal in women | journal = Horm Behav | volume = 59 | issue = 5 | pages = 754–64 | date = May 2011 | pmid = 21185838 | doi = 10.1016/j.yhbeh.2010.12.005 }}</ref>
			{{See also|Anabolic steroid#Adverse effects|Androgen replacement therapy#Adverse effects}}
			Adverse effects may also include minor side effects such as oily skin, acne, and seborrhea, as well as loss of scalp hair, which may be prevented or reduced with ]. In women, testosterone can produce ] (excessive facial/body hair growth), ], and other signs of ]. Exogenous testosterone may cause suppression of ] in men, leading to, in some cases, reversible ].<ref name="pmid1977002">{{cite journal | s2cid = 25825354 | title = Contraceptive efficacy of testosterone-induced azoospermia in normal men. World Health Organization Task Force on methods for the regulation of male fertility | journal = Lancet | volume = 336 | issue = 8721 | pages = 955–9 | date = October 1990 | pmid = 1977002 | doi = 10.1016/0140-6736(90)92416-F }}</ref> ] and ] may occur with high dosages of testosterone due to peripheral conversion of testosterone by ] into excessive amounts of the ] ].<ref>{{cite journal | vauthors = Rhoden EL, Morgentaler A | title = Treatment of testosterone-induced gynecomastia with the aromatase inhibitor, anastrozole | journal = International Journal of Impotence Research | volume = 16 | issue = 1 | pages = 95–7 | date = February 2004 | pmid = 14963480 | doi = 10.1038/sj.ijir.3901154 | doi-access = free }}</ref> Testosterone treatment, particularly in high dosages, can also be associated with ], increased ], increased ], ]s, and ]s.<ref name="Yates2000">{{cite journal| vauthors=Yates WR |title=Testosterone in Psychiatry |journal=Archives of General Psychiatry |volume=57 |issue=2 |year=2000 |pages=155 |issn=0003-990X |doi=10.1001/archpsyc.57.2.155}}</ref><ref name="pmid24016385">{{cite journal |vauthors=Johnson JM, Nachtigall LB, Stern TA |title=The effect of testosterone levels on mood in men: a review |journal=Psychosomatics |volume=54 |issue=6 |pages=509–514 |year=2013 |pmid=24016385 |doi=10.1016/j.psym.2013.06.018}}</ref><ref name="pmid6814798">{{cite journal |vauthors=Davidson JM, Kwan M, Greenleaf WJ |title=Hormonal replacement and sexuality in men |journal= Clinics in Endocrinology and Metabolism |volume=11 |issue=3 |pages=599–623 |date=November 1982 |pmid=6814798 |doi=10.1016/s0300-595x(82)80003-0}}</ref><ref name="BagatellBremner2003-144etc">{{cite book |vauthors=Bagatell C, Bremner WJ |title=Androgens in Health and Disease |url=https://books.google.com/books?id=vDcBCAAAQBAJ&pg=PA259|date=May 27, 2003|publisher=Springer Science & Business Media|isbn=978-1-59259-388-0|pages=144, 259–261, 351|access-date=November 18, 2016|archive-date=April 14, 2019 |archive-url=https://web.archive.org/web/20190414215125/https://books.google.com/books?id=vDcBCAAAQBAJ&pg=PA259|url-status=live}}</ref>
	Testosterone may prove to be an effective treatment in female sexual arousal disorders.<ref name="Bolour_2005">{{cite journal | author = Bolour S, Braunstein G | title = Testosterone therapy in women: a review | journal = Int. J. Impot. Res. | volume = 17 | issue = 5 | pages = 399–408 | year = 2005 | pmid = 15889125 | doi = 10.1038/sj.ijir.3901334 }}</ref> Currently there is no FDA approved androgen preparation for the treatment of androgen insufficiency, however it has been used off-label to treat low ] and sexual dysfunction in older women. Testosterone may be a treatment for postmenopausal women as long as they are effectively estrogenized.<ref name="Bolour_2005"/>
			Other side effects include increased ], which can require ] in order to treat, and exacerbation of ].<ref name=Pas2013>{{cite journal | vauthors = Pastuszak AW, Pearlman AM, Lai WS, Godoy G, Sathyamoorthy K, Liu JS, Miles BJ, Lipshultz LI, Khera M | title = Testosterone replacement therapy in patients with prostate cancer after radical prostatectomy | journal = The Journal of Urology | volume = 190 | issue = 2 | pages = 639–44 | date = Aug 2013 | pmid = 23395803 | pmc = 4544840 | doi = 10.1016/j.juro.2013.02.002 }}</ref>
	==== Behavior and personality ====
	Testosterone levels play a major role in risk-taking during financial decisions.<ref name="pmid19706398">{{cite journal | author = Sapienza P, Zingales L, Maestripieri D | title = Gender differences in financial risk aversion and career choices are affected by testosterone | journal = Proc. Natl. Acad. Sci. U.S.A. | volume = 106 | issue = 36 | pages = 15268–73 | date = September 2009 | pmid = 19706398 | pmc = 2741240 | doi = 10.1073/pnas.0907352106 | bibcode = 2009PNAS..10615268S }}</ref><ref name="Apicella_2008">{{cite journal | author = Apicella CL, Dreber A, Campbell B, Gray PB, Hoffman M, Little AC | title = Testosterone and financial risk preferences | journal = Evolution and Human Behavior | volume = 29 | issue = 6 | pages = 384–390 |date=November 2008 | pmid = | doi = 10.1016/j.evolhumbehav.2008.07.001 | url = }}</ref>
			The FDA stated in 2015 that neither the benefits nor the safety of testosterone have been established for low testosterone levels due to aging.<ref name="FDA2015"/> The FDA has required that testosterone pharmaceutical labels include warning information about the possibility of an increased risk of heart attacks and stroke.<ref name=FDA2015/> They have also required the label include concerns about abuse and dependence.<ref>{{cite web|title=Testosterone and Other Anabolic Androgenic Steroids (AAS): FDA Statement - Risks Associated With Abuse and Dependence |url=https://www.fda.gov/Safety/MedWatch/SafetyInformation/SafetyAlertsforHumanMedicalProducts/ucm526151.htm |website=]|access-date=October 26, 2016|date=October 25, 2016|url-status=live|archive-url=https://web.archive.org/web/20161027052404/https://www.fda.gov/Safety/MedWatch/SafetyInformation/SafetyAlertsforHumanMedicalProducts/ucm526151.htm |archive-date=October 27, 2016}}</ref>
	=== Brain ===
	As testosterone affects the entire body (often by enlarging; males have bigger hearts, lungs, liver, etc.), the brain is also affected by this "sexual" differentiation;<ref name="pmid19403051"/> the ] ] converts testosterone into ] that is responsible for ] of the brain in male mice. In humans, masculinization of the fetal brain appears, by observation of gender preference in patients with ]s of androgen formation or androgen receptor function, to be associated with functional androgen receptors.<ref name="pmid11534997">{{cite journal | author = Wilson JD | title = Androgens, androgen receptors, and male gender role behavior | journal = Horm Behav | volume = 40 | issue = 2 | pages = 358–66 | date = September 2001 | pmid = 11534997 | doi = 10.1006/hbeh.2001.1684 }}</ref>
			Injectable forms of testosterone can cause a lung problem called pulmonary oil microembolism (POME). Symptoms of POME include cough, shortness of breath, tightening of the throat, chest pain, sweating, dizziness, and fainting.<ref>{{Cite web|date=August 2, 2020|title=Testosterone Injection|website=Drugs.com |url=https://www.drugs.com/testosterone.html|access-date=January 4, 2021|archive-date=January 8, 2021|archive-url=https://web.archive.org/web/20210108041736/https://www.drugs.com/testosterone.html|url-status=live}}</ref><ref>{{Cite web|date=March 15, 2019|title=Testosterone Injection|website=MedlinePlus |url=https://medlineplus.gov/druginfo/meds/a614041.html|access-date=January 4, 2021|archive-url=https://web.archive.org/web/20191223210513/https://medlineplus.gov/druginfo/meds/a614041.html|archive-date=December 23, 2019|url-status=live}}</ref> A postmarketing analysis by the manufacturer of Aveed (testosterone undeconate injection) found that POME occurred at a rate of less than 1% per injection per year for Aveed.<ref>{{cite journal |vauthors=Pastuszak AW, Hu Y, Freid JD |title=Occurrence of Pulmonary Oil Microembolism After Testosterone Undecanoate Injection: A Postmarketing Safety Analysis |journal=Sexual Medicine |volume=8 |issue=2 |pages=237–242 |date=June 2020 |pmid=32184081 |pmc=7261689 |doi=10.1016/j.esxm.2020.01.009}}</ref>
	There are some differences between a male and female brain (possibly the result of different testosterone levels), one of them being size: the male human brain is, on average, larger.<ref name="pmid17544382">{{cite journal | author = Cosgrove KP, Mazure CM, Staley JK | title = Evolving knowledge of sex differences in brain structure, function, and chemistry | journal = Biol. Psychiatry | volume = 62 | issue = 8 | pages = 847–55 | date = October 2007 | pmid = 17544382 | pmc = 2711771 | doi = 10.1016/j.biopsych.2007.03.001 }}</ref> In a Danish study from 2003, men were found to have a total myelinated fiber length of 176,000&nbsp;km at the age of 20, whereas in women the total length was 149,000&nbsp;km (approx. 15% less).<ref name="pmid12794739">{{cite journal | author = Marner L, Nyengaard JR, Tang Y, Pakkenberg B | title = Marked loss of myelinated nerve fibers in the human brain with age | journal = J. Comp. Neurol. | volume = 462 | issue = 2 | pages = 144–52 | date = July 2003 | pmid = 12794739 | doi = 10.1002/cne.10714 }}</ref>
			===Long-term adverse effects===
	A study conducted in 1996 found no immediate short term effects on mood or behavior from the administration of ] doses of testosterone for 10 weeks on 43 healthy men.<ref name="pmid8637535"/> Another study found a correlation between testosterone and risk tolerance in career choice among women.<ref>{{cite journal | author = Sapienza P, Zingales L, Maestripieri D | title = Gender differences in financial risk aversion and career choices are affected by testosterone | journal = Proc Natl Acad Sci USA | volume = 106 | issue = 36 | pages = 15268–15273 | year = 2009 | pmid = 19706398 | pmc = 2741240 | doi = 10.1073/pnas.0907352106 | url = http://www.pnas.org/content/early/2009/08/20/0907352106 | bibcode = 2009PNAS..10615268S }}</ref><ref>{{cite web | url = http://www.npr.org/templates/story/story.php?storyId=112334459 | title = Testosterone Affects Some Women's Career Choices | date = August 28, 2009 | publisher = NPR}}</ref>
			====Cardiovascular disease====
	The literature suggests that attention, memory, and spatial ability are key cognitive functions affected by testosterone in humans. Preliminary evidence suggests that low testosterone levels may be a risk factor for cognitive decline and possibly for ] of the Alzheimer's type,<ref name="pmid15582279">{{cite journal | author = Hogervorst E, Bandelow S, Combrinck M, Smith AD | title = Low free testosterone is an independent risk factor for Alzheimer's disease | journal = Exp. Gerontol. | volume = 39 | issue = 11–12 | pages = 1633–9 | year = 2004 | pmid = 15582279 | doi = 10.1016/j.exger.2004.06.019 }}</ref><ref name="pmid14745052">{{cite journal | author = Moffat SD, Zonderman AB, Metter EJ, Kawas C, Blackman MR, Harman SM, Resnick SM | title = Free testosterone and risk for Alzheimer disease in older men | journal = Neurology | volume = 62 | issue = 2 | pages = 188–93 | date = January 2004 | pmid = 14745052 | doi = 10.1212/WNL.62.2.188 }}</ref><ref name="pmid16785599">{{cite journal | author = Pike CJ, Rosario ER, Nguyen TV | title = Androgens, aging, and Alzheimer's disease | journal = Endocrine | volume = 29 | issue = 2 | pages = 233–41 | date = April 2006 | pmid = 16785599 | doi = 10.1385/ENDO:29:2:233 }}</ref><ref name="pmid15383512">{{cite journal | author = Rosario ER, Chang L, Stanczyk FZ, Pike CJ | title = Age-related testosterone depletion and the development of Alzheimer disease | journal = JAMA | volume = 292 | issue = 12 | pages = 1431–2 | date = September 2004 | pmid = 15383512 | doi = 10.1001/jama.292.12.1431-b }}</ref> a key argument in ] medicine for the use of testosterone in anti-aging therapies. Much of the literature, however, suggests a curvilinear or even quadratic relationship between spatial performance and circulating testosterone,<ref name="pmid8817730">{{cite journal | author = Moffat SD, Hampson E | title = A curvilinear relationship between testosterone and spatial cognition in humans: possible influence of hand preference | journal = Psychoneuroendocrinology | volume = 21 | issue = 3 | pages = 323–37 | date = April 1996 | pmid = 8817730 | doi = 10.1016/0306-4530(95)00051-8 }}</ref> where both hypo- and hypersecretion (deficient- and excessive-secretion) of circulating androgens have negative effects on cognition.
			{{See also|Testosterone and the cardiovascular system}}
			Adverse effects of testosterone supplementation may include increased cardiovascular events (including ]s and ]s) and ]s based on three peer-reviewed studies involving men taking testosterone replacement.<ref>{{cite journal | vauthors = Finkle WD, Greenland S, Ridgeway GK, Adams JL, Frasco MA, Cook MB, Fraumeni JF, Hoover RN | title = Increased risk of non-fatal myocardial infarction following testosterone therapy prescription in men | journal = PLOS ONE | volume = 9 | issue = 1 | page = e85805 | date = January 2014 | pmid = 24489673 | pmc = 3905977 | doi = 10.1371/journal.pone.0085805 | bibcode = 2014PLoSO...985805F | doi-access = free }}</ref> In addition, an increase of 30% in deaths and heart attacks in older men has been reported.<ref name="pmid24193080">{{cite journal | vauthors = Vigen R, O'Donnell CI, Barón AE, Grunwald GK, Maddox TM, Bradley SM, Barqawi A, Woning G, Wierman ME, Plomondon ME, Rumsfeld JS, Ho PM | title = Association of testosterone therapy with mortality, myocardial infarction, and stroke in men with low testosterone levels | journal = JAMA | volume = 310 | issue = 17 | pages = 1829–36 | date = Nov 2013 | pmid = 24193080 | doi = 10.1001/jama.2013.280386 | doi-access = free }}</ref> Due to an increased incidence of adverse cardiovascular events compared to a ], a Testosterone in Older Men with Mobility Limitations (TOM) trial (a ] randomized trial) was halted early by the ].<ref>{{cite journal | vauthors = Basaria S, Coviello AD, Travison TG, Storer TW, Farwell WR, Jette AM, Eder R, Tennstedt S, Ulloor J, Zhang A, Choong K, Lakshman KM, Mazer NA, Miciek R, Krasnoff J, Elmi A, Knapp PE, Brooks B, Appleman E, Aggarwal S, Bhasin G, Hede-Brierley L, Bhatia A, Collins L, LeBrasseur N, Fiore LD, Bhasin S | title = Adverse events associated with testosterone administration | journal = The New England Journal of Medicine | volume = 363 | issue = 2 | pages = 109–22 | date = July 8, 2010 | pmid = 20592293 | pmc = 3440621 | doi = 10.1056/NEJMoa1000485 }}</ref> On January 31, 2014, reports of ]s, ]s, and ]s in men taking FDA-approved testosterone-replacement led the FDA to announce that it would be investigating the issue.<ref name="FDA-20140131">{{cite web |author=Staff |title=FDA evaluating risk of stroke, heart attack and death with FDA-approved testosterone products |url=https://www.fda.gov/downloads/Drugs/DrugSafety/UCM383909.pdf |publisher=] |date=January 31, 2014 |access-date=September 17, 2014 |url-status=live |archive-url=https://web.archive.org/web/20140219213907/https://www.fda.gov/downloads/Drugs/DrugSafety/UCM383909.pdf |archive-date=February 19, 2014}}</ref> Later, in September 2014, the FDA announced, as a result of the "potential for adverse cardiovascular outcomes", a review of the appropriateness and safety of Testosterone Replacement Therapy (TRT).<ref name="NYT-20140917">{{cite news | vauthors = Tavernise S | title = F.D.A. Panel Backs Limits on Testosterone Drugs | url = https://www.nytimes.com/2014/09/18/health/testosterone-drugs-fda.html | date = September 17, 2014 | work=] | access-date = September 18, 2014 | url-status = live | archive-url = https://web.archive.org/web/20140917201336/http://www.nytimes.com/2014/09/18/health/testosterone-drugs-fda.html | archive-date = September 17, 2014}}</ref><ref name="CNN-20140905">{{cite news |author=Staff |title=FDA Panel To Review Testosterone Therapy Appropriateness and Safety |url=http://ireport.cnn.com/docs/DOC-1167887 |date=September 5, 2014 |work=] |access-date=September 14, 2014 |url-status=dead |archive-url=https://web.archive.org/web/20140911081501/http://ireport.cnn.com/docs/DOC-1167887 |archive-date=September 11, 2014}}</ref><ref name="FDA-20140903">{{cite web |author=Staff |title=Joint Meeting for Bone, Reproductive and Urologic Drugs Advisory Committee (BRUDAC) and the Drug Safety And Risk Management Advisory Committee (DSARM AC) – FDA background documents for the discussion of two major issues in testosterone replacement therapy (TRT): 1. The appropriate indicated population for TRT, and 2. The potential for adverse cardiovascular outcomes associated with use of TRT |url=https://www.fda.gov/downloads/AdvisoryCommittees/CommitteesMeetingMaterials/Drugs/ReproductiveHealthDrugsAdvisoryCommittee/UCM412536.pdf |date=September 17, 2014 |work=] |access-date=September 14, 2014 |url-status=live |archive-url=https://web.archive.org/web/20140906043632/https://www.fda.gov/downloads/AdvisoryCommittees/CommitteesMeetingMaterials/Drugs/ReproductiveHealthDrugsAdvisoryCommittee/UCM412536.pdf |archive-date=September 6, 2014}}</ref> The FDA now requires warnings in the drug labeling of all approved testosterone products regarding ] and ].<ref>{{cite web|author=Staff|title=FDA adding general warning to testosterone products about potential for venous blood clots|url=https://www.fda.gov/Drugs/DrugSafety/ucm401746.htm|website=]|access-date=October 9, 2014|date=June 19, 2014|url-status=live|archive-date=October 6, 2014|archive-url=https://web.archive.org/web/20141006074106/https://www.fda.gov/Drugs/DrugSafety/ucm401746.htm}}</ref>
	=== Aggression and criminality ===
	{{See also|Aggression#Testosterone|biosocial criminology}}
	The "evolutionary neuroandrogenic theory" focuses on the hormone testosterone as a factor influencing aggression and criminality and being evolutionarily beneficial during certain forms of competition. In most species, males are more aggressive than females. Castration of males usually has a pacifying effect on their aggressive behavior. In humans, males engage in crime and especially violent crime more than females. Their involvement in crime usually rises in the early teens to mid teens, at the same time as testosterone levels rise. Research on the relationship between testosterone and aggression is difficult, since the only reliable measurement of brain testosterone is by a ] that is not done for research purposes. Studies therefore have often instead used more unreliable measurements from blood or saliva.{{citation needed|date=December 2013}}
			Up to the year 2010, studies had not shown any effect on the risk of death, ] or ];<ref name="pmid17285783">{{cite journal | vauthors = Haddad RM, Kennedy CC, Caples SM, Tracz MJ, Boloña ER, Sideras K, Uraga MV, Erwin PJ, Montori VM | title = Testosterone and cardiovascular risk in men: a systematic review and meta-analysis of randomized placebo-controlled trials | journal = Mayo Clinic Proceedings | volume = 82 | issue = 1 | pages = 29–39 | date = Jan 2007 | pmid = 17285783 | doi = 10.4065/82.1.29 }}</ref><ref name=Fer2010>{{cite journal | vauthors = Fernández-Balsells MM, Murad MH, Lane M, Lampropulos JF, Albuquerque F, Mullan RJ, Agrwal N, Elamin MB, Gallegos-Orozco JF, Wang AT, Erwin PJ, Bhasin S, Montori VM | title = Clinical review 1: Adverse effects of testosterone therapy in adult men: a systematic review and meta-analysis | journal = The Journal of Clinical Endocrinology and Metabolism | volume = 95 | issue = 6 | pages = 2560–75 | date = Jun 2010 | pmid = 20525906 | doi = 10.1210/jc.2009-2575 | doi-access = free }}</ref> more recent{{when|date=January 2020}} studies, however, do raise concerns.<ref>{{cite web|title=Testosterone Products: Drug Safety Communication – FDA Investigating Risk of Cardiovascular Events|work=]|date=January 31, 2014 |url=https://www.fda.gov/Safety/MedWatch/SafetyInformation/SafetyAlertsforHumanMedicalProducts/ucm384225.htm |access-date=February 3, 2014|url-status=live|archive-date=February 14, 2014|archive-url=https://web.archive.org/web/20140214183006/https://www.fda.gov/Safety/MedWatch/SafetyInformation/SafetyAlertsforHumanMedicalProducts/ucm384225.htm}}</ref> A 2013 study, published in the Journal of the American Medical Association, reported "the use of testosterone therapy was significantly associated with increased risk of adverse outcomes." The study began after a previous, randomized, clinical trial of testosterone therapy in men was stopped prematurely "due to adverse cardiovascular events raising concerns about testosterone therapy safety."<ref name="pmid24193080"/>
	Most studies support a link between adult criminality and testosterone, although the relationship is modest if examined separately for each sex. Nearly all studies of juvenile delinquency and testosterone are not significant. Most studies have also found testosterone to be associated with behaviors or personality traits linked with criminality such as ] and ]. Many studies have also been done on the relationship between more general aggressive behavior/feelings and testosterone. About half the studies have found a relationship and about half no relationship.<ref name="isbn0-12-373612-9">{{cite book | author = Wright J, Ellis L, Beaver K | title = Handbook of crime correlates | publisher = Academic Press | location = San Diego | year = 2009 | pages =208–210 | isbn = 0-12-373612-9 }}</ref>
			However, when given to men with hypogonadism in the short- and medium-term, testosterone replacement therapy does not increase the risk of cardiovascular events (including strokes and heart attacks and other heart diseases). The long-term safety of the therapy is not known yet.<ref>{{Cite journal |date=February 6, 2023 |title=Research provides reassurance about the safety of testosterone treatment |url=https://evidence.nihr.ac.uk/alert/research-provides-reassurance-about-safety-testosterone-treatment/ |journal=NIHR Evidence |type=Plain English summary |publisher=National Institute for Health and Care Research |doi=10.3310/nihrevidence_56696 |s2cid=257851823 |access-date=February 28, 2023 |archive-date=February 28, 2023 |archive-url=https://web.archive.org/web/20230228091540/https://evidence.nihr.ac.uk/alert/research-provides-reassurance-about-safety-testosterone-treatment/ |url-status=live }}</ref><ref>{{cite journal | vauthors = Hudson J, Cruickshank M, Quinton R, Aucott L, Aceves-Martins M, Gillies K, Bhasin S, Snyder PJ, Ellenberg SS, Grossmann M, Travison TG, Gianatti EJ, van der Schouw YT, Emmelot-Vonk MH, Giltay EJ, Hackett G, Ramachandran S, Svartberg J, Hildreth KL, Groti Antonic K, Brock GB, Tenover JL, Tan HM, Kong CH, Tan WS, Marks LS, Ross RJ, Schwartz RS, Manson P, Roberts S, Andersen MS, Magnussen LV, Hernández R, Oliver N, Wu F, Dhillo WS, Bhattacharya S, Brazzelli M, Jayasena CN | title = Adverse cardiovascular events and mortality in men during testosterone treatment: an individual patient and aggregate data meta-analysis | journal = The Lancet. Healthy Longevity | volume = 3 | issue = 6 | pages = e381–e393 | date = June 2022 | pmid = 35711614 | pmc = 9184259 | doi = 10.1016/S2666-7568(22)00096-4 }}</ref>
	Testosterone is only one of many factors that influence aggression and the effects of previous experience and environmental stimuli have been found to correlate more strongly. A few studies indicate that the testosterone derivative ] (one form of ]) might play an even more important role in male aggression.<ref name="isbn0-12-373612-9"/><ref>Goldman D, Lappalainen J, Ozaki N. Direct analysis of candidate genes in impulsive disorders. In: Bock G, Goode J, eds. Genetics of Criminal and Antisocial Behaviour. Ciba Foundation Symposium 194. Chichester: John Wiley & Sons; 1996.</ref><ref>{{cite journal | author = Coccaro E | year = 1996 | title = Neurotransmitter correlates of impulsive aggression in humans. In: Ferris C, Grisso T, eds. Understanding Aggressive Behaviour inn Children | url = | journal = Annals of the New York Academy of Sciences | volume = 794 | issue = | pages = 82–89 | doi=10.1111/j.1749-6632.1996.tb32511.x}}</ref><ref>{{cite journal | author = Finkelstein J., Susman E., Chinchilli V., Kunselman S., D'Arcangelo M. R., Schwab J., Demers L., Liben L., Lookingbill G., Kulin H. E. | year = 1997 | title = Estrogen or testosterone increases self-reported aggressive behaviors in hypogonadal adolescents | url = | journal = Journal of Clinical Endocrinology and Metabolism | volume = 82 | issue = 8| pages = 2433–2438 | doi=10.1210/jc.82.8.2433}}</ref>
	It has been empirically shown that boys who had a history of high physical aggression, from age 6 to 12, were found to have lower testosterone levels at age 13 compared with boys with no history of high physical aggression. The former were also failing in school and were unpopular with their peers. Both concurrent and longitudinal analyses indicate that testosterone levels were positively associated with social success rather than with physical aggression.<ref>Journal of the American Academy of Child & Adolescent Psychiatry – Volume 35, Issue 10 , Pages 1322–1330, October 1996</ref>
			====Benign prostatic hyperplasia====
	A study at the Universities of Zurich and Royal Holloway London with more than 120 experimental subjects has shown that the sexual hormone can encourage fair behavior. For the study subjects took part in a behavioral experiment where the distribution of a real amount of money was decided. The rules allowed both fair and unfair offers. The negotiating partner could subsequently accept or decline the offer. The fairer the offer, the less probable a refusal by the negotiating partner. If no agreement was reached, neither party earned anything. Test subjects with an artificially enhanced testosterone level generally made better, fairer offers than those who received placebos, thus reducing the risk of a rejection of their offer to a minimum. Two later studies have empirically confirmed these results.<ref>"Prejudice and truth about the effect of testosterone on human bargaining behaviour" – C. Eisenegger, M. Naef R. Snozzi1, M. Heinrichs & E. Fehr – Nature 463, 356–359 (January 21, 2010) | doi:10.1038/nature08711; Received September 15, 2009; Accepted November 30, 2009; Published online December 8, 2009</ref><ref>"New evidence on testosterone and cooperation" – Jack van Honk, Estrella R. Montoya, Peter A. Bos, Mark van Vugt & David Terburg – Nature 485, E4–E5 (May 24, 2012) doi:10.1038/nature11136 Received October 19, 2011 Accepted March 13, 2012 Published online May 23, 2012</ref><ref>Eisenegger et al. reply – C. Eisenegger, M. Naef, R. Snozzi, M. Heinrichs & E. Fehr – Nature 485, E5–E6 (May 24, 2012) {{DOI|10.1038/nature11137}}</ref>
			Testosterone therapy for patients with late-onset hypogonadism, in addition to increasing risk of cardiovascular disease and prostate cancer, may exacerbate the risk factors associated with ], a condition that involves the noncancerous enlargement of the prostate gland, which can lead to urinary symptoms.<ref name="pmid35266057">{{cite journal |vauthors=Snyder P |title=Testosterone treatment of late-onset hypogonadism - benefits and risks |journal=Rev Endocr Metab Disord |volume=23 |issue=6 |pages=1151–1157 |date=December 2022 |pmid=35266057 |doi=10.1007/s11154-022-09712-1}}</ref>
			====Prostate cancer====
	Estradiol is known to correlate with aggression in male mice.<ref name="pmid18280561">{{cite journal | author = Soma KK, Scotti MA, Newman AE, Charlier TD, Demas GE | title = Novel mechanisms for neuroendocrine regulation of aggression | journal = Front Neuroendocrinol | volume = 29 | issue = 4 | pages = 476–89 | date = October 2008 | pmid = 18280561 | doi = 10.1016/j.yfrne.2007.12.003 | url = }}</ref> Moreover, the conversion of testosterone to estradiol regulates male aggression in ] during breeding season.<ref name="pmid11016791">{{cite journal | author = Soma KK, Sullivan KA, Tramontin AD, Saldanha CJ, Schlinger BA, Wingfield JC | title = Acute and chronic effects of an aromatase inhibitor on territorial aggression in breeding and nonbreeding male song sparrows | journal = J. Comp. Physiol. A | volume = 186 | issue = 7–8 | pages = 759–69 | year = 2000 | pmid = 11016791 | doi = 10.1007/s003590000129 }}</ref>
			Testosterone in the presence of a slow-growing prostate cancer is assumed to increase its growth rate. However, the association between testosterone supplementation and the development of prostate cancer is unproven.<ref name="pmid19863857">{{cite journal | vauthors = Rhoden EL, Averbeck MA | s2cid = 20250546 | title = Testosterone therapy and prostate carcinoma | journal = Current Urology Reports | volume = 10 | issue = 6 | pages = 453–59 | date = Nov 2009 | pmid = 19863857 | doi = 10.1007/s11934-009-0072-1 }}</ref> Nevertheless, physicians are cautioned about the cancer risk associated with testosterone supplementation.<ref name="pmid16006887">{{cite journal | vauthors = Gaylis FD, Lin DW, Ignatoff JM, Amling CL, Tutrone RF, Cosgrove DJ | title = Prostate cancer in men using testosterone supplementation | journal = The Journal of Urology | volume = 174 | issue = 2 | pages = 534–38; discussion 538 | date = Aug 2005 | pmid = 16006887 | doi = 10.1097/01.ju.0000165166.36280.60 }}</ref>
			Testosterone may accelerate pre-existing ] growth in individuals who have undergone androgen deprivation.<ref name=Pas2013/> It is recommended that physicians screen for prostate cancer with a digital rectal exam and ] (PSA) level before starting therapy, and monitor PSA and hematocrit levels closely during therapy.<ref name="auto"/>
	== Medical uses ==
	The primary use of testosterone is the treatment of males with too little or no natural endogenous testosterone production—males with ].{{citation needed|date=October 2014}} This is known as hormone replacement therapy or testosterone replacement therapy (TRT), which maintains serum testosterone levels in the normal range.
			Ethnic groups have different rates of prostate cancer.<ref name=Cal2010/> Differences in sex hormones, including testosterone, have been suggested as an explanation for these differences.<ref name=Cal2010>{{cite journal |vauthors=Calistro Alvarado L |title=Population differences in the testosterone levels of young men are associated with prostate cancer disparities in older men |journal=American Journal of Human Biology |volume=22 |issue=4 |pages=449–455 |year=2010 |pmid=20087895 |doi=10.1002/ajhb.21016 |s2cid=21117845}}</ref> This apparent paradox can be resolved by noting that prostate cancer is very common. In autopsies, 80% of 80-year-old men have prostate cancer.<ref name="pmid15495199">{{cite journal |vauthors=Bostwick DG, Burke HB, Djakiew D, Euling S, Ho SM, Landolph J, Morrison H, Sonawane B, Shifflett T, Waters DJ, Timms B |title=Human prostate cancer risk factors |journal=Cancer |volume=101 |issue=10 Suppl |pages=2371–2490 |date=Nov 2004 |pmid=15495199 |doi=10.1002/cncr.20408 |s2cid=24807561}}</ref>
	Testosterone has also been given for many other purposes besides replacement. Examples include reducing ], correcting lack of libido or erectile dysfunction, correcting ], encouraging ], encouraging height growth, encouraging ] stimulation and reversing the effects of ], and appetite stimulation. By the late 1940s, testosterone was being touted as an anti-aging wonder drug (e.g., see ]'s ''The Male Hormone'').<ref name = "de Kruif_1945"/> Decline of testosterone production with age has led to interest in ].<ref name="pmid16985841">{{cite journal | author = Myers JB, Meacham RB | title = Androgen Replacement Therapy in the Aging Male | journal = Rev Urol | volume = 5 | issue = 4 | pages = 216–26 | year = 2003 | pmid = 16985841 | pmc = 1508369 | doi = | url = }}</ref>
			===Pregnancy and breastfeeding===
	Testosterone may be used as a monotherapy in ] and minor depression or as an augmentation therapy in major depression in middle-aged men with low testosterone. However, review of the current literature does not show a statistically significant impact on the mood of the men with normal levels of testosterone or on the mood of the older men with low testosterone.<ref name="pmid24501728">{{cite journal | author = Amanatkar HR, Chibnall JT, Seo BW, Manepalli JN, Grossberg GT | title = Impact of exogenous testosterone on mood: a systematic review and meta-analysis of randomized placebo-controlled trials | journal = Ann Clin Psychiatry | volume = 26 | issue = 1 | pages = 19–32 | year = 2014 | pmid = 24501728 | doi = | url = http://www.aacp.com/pdf%2F0214%2F0214ACP%5FAmanatkar%2Epdf }}</ref>
			Testosterone is ] in ] and not recommended during ].<ref>{{cite web|title=Testosterone Pregnancy and Breastfeeding Warnings |url=https://www.drugs.com/pregnancy/testosterone.html|access-date=February 1, 2014|url-status=live|archive-url=https://web.archive.org/web/20140201201902/http://www.drugs.com/pregnancy/testosterone.html|archive-date=February 1, 2014}}</ref> Androgens like testosterone are ]s and are known to cause ] harm, such as producing ] and ].
			==Interactions==
	To take advantage of its ] effects, testosterone is often administered to ] as part of the ],<ref>{{cite web | url=http://www.nhs.uk/Conditions/Gender-dysphoria/Pages/Treatment.aspx | title=Gender dysphoria – Treatment | publisher=NHS Gov.uk | date=Page last reviewed: May 21, 2012 | accessdate=October 31, 2013}}</ref> with a "target level" of the normal male testosterone level. Likewise, ] are sometimes prescribed ] to decrease the level of testosterone in the body and allow for the effects of estrogen to develop.
			===5α-Reductase inhibitors===
	Testosterone therapy may improve the management of ].<ref name="pmid18772488">{{cite journal | author = Traish AM, Saad F, Guay A | title = The dark side of testosterone deficiency: II. Type 2 diabetes and insulin resistance | journal = J. Androl. | volume = 30 | issue = 1 | pages = 23–32 | year = 2009 | pmid = 18772488 | doi = 10.2164/jandrol.108.005751 | url = }}</ref> Low testosterone has been associated with the development of ].<ref name="pmid16785599"/><ref name="pmid15383512"/> A small trial in 2005 showed mixed results in using testosterone to combat the effects of aging.<ref name="pmid18167405">{{cite journal | author = Emmelot-Vonk MH, Verhaar HJ, Nakhai Pour HR, Aleman A, Lock TM, Bosch JL, Grobbee DE, van der Schouw YT | title = Effect of testosterone supplementation on functional mobility, cognition, and other parameters in older men: a randomized controlled trial | journal = JAMA | volume = 299 | issue = 1 | pages = 39–52 | date = January 2008 | pmid = 18167405 | doi = 10.1001/jama.2007.51 | url = }}</ref>
			]s like ] and ] can slightly increase circulating levels of testosterone by inhibiting its ].<ref name="JamesonKretser2013">{{cite book | vauthors = Jameson JL, de Kretser DM, Marshall JC, De Groot JL | title = Endocrinology Adult and Pediatric: Reproductive Endocrinology | url = https://books.google.com/books?id=Np8xxP6pcdUC&pg=RA1-PT1157 | date = May 7, 2013 | publisher = Elsevier Health Sciences | isbn = 978-0-323-22152-8 | pages = 1– | url-status = live | archive-url = https://web.archive.org/web/20170908214106/https://books.google.com/books?id=Np8xxP6pcdUC&pg=RA1-PT1157 | archive-date = September 8, 2017}}</ref> However, these drugs do this via prevention of the conversion of testosterone into its more potent ] ] (DHT), and this results in dramatically reduced circulating levels of DHT (which circulates at much lower relative concentrations).<ref name="JamesonKretser2013" /><ref name="Blume-PeytaviWhiting2008">{{cite book | vauthors = Blume-Peytavi U, Whiting DA, Trüeb RM | title = Hair Growth and Disorders | url = https://books.google.com/books?id=pHrX2-huQCoC&pg=PA182 | date = June 26, 2008 | publisher = Springer Science & Business Media | isbn = 978-3-540-46911-7 | pages = 182– | url-status = live | archive-url = https://web.archive.org/web/20170908214106/https://books.google.com/books?id=pHrX2-huQCoC&pg=PA182 | archive-date = September 8, 2017}}</ref> In addition, local levels of DHT in so-called androgenic (5α-reductase-expressing) tissues are also markedly reduced,<ref name="JamesonKretser2013" /><ref name="Blume-PeytaviWhiting2008" /> and this can have a strong impact on certain effects of testosterone.<ref name="Llewellyn2011" /><ref name="BagatellBremner2003-p78">{{cite book | vauthors = Bagatelle C, Bremner WJ | title = Androgens in Health and Disease | url = https://books.google.com/books?id=vDcBCAAAQBAJ&pg=PA78 | date = May 27, 2003 | publisher = Springer Science & Business Media | isbn = 978-1-59259-388-0 | pages = 78– | access-date = December 6, 2016 | archive-date = April 14, 2019 | archive-url = https://web.archive.org/web/20190414215015/https://books.google.com/books?id=vDcBCAAAQBAJ&pg=PA78 | url-status = live }}</ref> For instance, growth of body and facial hair and ] induced by testosterone may be inhibited by 5α-reductase inhibitors, and this could be considered undesirable in the context of, for instance, ].<ref name="BagatellBremner2003-p78" /><ref name="Baskin2012">{{cite book|vauthors=Baskin LS|title=Hypospadias and Genital Development|url=https://books.google.com/books?id=8zfaBwAAQBAJ&pg=PA37|date=December 6, 2012|publisher=Springer Science & Business Media|isbn=978-1-4419-8995-6|pages=37–|access-date=December 6, 2016|archive-date=April 14, 2019|archive-url=https://web.archive.org/web/20190414215056/https://books.google.com/books?id=8zfaBwAAQBAJ&pg=PA37|url-status=live}}</ref> On the other hand, 5α-reductase inhibitors may prevent or reduce adverse androgenic side effects of testosterone like ], ], ], and ].<ref name="Llewellyn2011" /> In addition to the prevention of testosterone conversion into DHT, 5α-reductase inhibitors also prevent the formation of ]s like ] from testosterone, and this may have neuropsychiatric consequences in some men.<ref name="Frontiers">{{cite book|title=Neurosteroids|url=https://books.google.com/books?id=fSgNRlZUwt0C&pg=PA358|publisher=Frontiers E-books|isbn=978-2-88919-078-2|pages=357–358|access-date=December 6, 2016|archive-date=April 14, 2019|archive-url=https://web.archive.org/web/20190414214952/https://books.google.com/books?id=fSgNRlZUwt0C&pg=PA358|url-status=live}}</ref>
			===Aromatase inhibitors===
	=== Hormone replacement therapy ===
			]s like ] prevent the conversion of testosterone into ] by ].<ref name="Llewellyn2011" /> As only a very small fraction of testosterone is converted into estradiol, this does not affect testosterone levels, but it can prevent ]ic side effects like gynecomastia that can occur when testosterone is administered at relatively high dosages.<ref name="Llewellyn2011" /> However, estradiol exerts ] on the ] and, for this reason, prevention of its formation can reduce this feedback and disinhibit gonadal production of testosterone, which in turn can increase levels of endogenous testosterone.<ref name="pmid14623515">{{cite journal | vauthors = Simpson ER | s2cid = 11210435 | title = Sources of estrogen and their importance | journal = J. Steroid Biochem. Mol. Biol. | volume = 86 | issue = 3–5 | pages = 225–30 |date=September 2003 | pmid = 14623515 | doi = 10.1016/S0960-0760(03)00360-1 }}</ref> Testosterone therapy is sometimes combined with an aromatase inhibitor for men with secondary hypogonadism who wish to conceive children with their partners.<ref name="Nieschlag2010">{{cite book |veditors=Nieschlag E, Behre HM, Nieschlag S |title=Andrology: Male Reproductive Health and Dysfunction |date=2009 |publisher=Springer |location=Berlin |isbn=978-3-540-78354-1 |page=459 |edition=3rd}}</ref>
	{{Further|Testosterone#Adverse effects|Andropause#Hormone replacement therapy|Androgen replacement therapy#Adverse effects}}
	Testosterone levels decline gradually with age in human beings.(see ]) The clinical significance of this decrease is debated (see ]). There is disagreement about when to treat aging men with testosterone replacement therapy. The ]'s position is that "testosterone replacement therapy in aging men is indicated when both clinical symptoms and signs suggestive of ] and decreased testosterone levels are present."<ref name="pmid16474019">{{cite journal | title = Testosterone replacement therapy for male aging: ASA position statement | journal = J. Androl. | volume = 27 | issue = 2 | pages = 133–4 | year = 2006 | pmid = 16474019 | doi = }}</ref> The ] says "] is defined as a free testosterone level that is below the lower limit of normal for young adult control subjects. Previously, age-related decreases in free testosterone were once accepted as normal. Currently, they are not considered normal.<ref></ref>{{check|date=January 2015}} Males with borderline testosterone levels may benefit from a trial of testosterone.<ref name="pmid12917096">{{cite journal | author = Guay AT, Spark RF, Bansal S, Cunningham GR, Goodman NF, Nankin HR, Petak SM, Perez JB | title = American Association of Clinical Endocrinologists medical guidelines for clinical practice for the evaluation and treatment of male sexual dysfunction: a couple's problem—2003 update | journal = Endocr Pract | volume = 9 | issue = 1 | pages = 77–95 | year = 2003 | pmid = 12917096 | doi = 10.4158/EP.9.1.77 | url = http://aace.metapress.com/content/9j3jxth5vc3nqd9l/fulltext.pdf }}</ref> Large-scale trials to assess the effectiveness and long-term safety of testosterone are still lacking.<ref name="url_ Cunningham">{{cite web | url = http://www.endocrinetoday.com/view.aspx?rid=29171 | title = Testosterone treatment in aging men | author = Cunningham GR | date = June 25, 2008 | work = | publisher = EndocrineToday.com | accessdate = July 17, 2009}}</ref>
			===Cytochrome P450 inhibitors===
	There is not total agreement on the threshold of testosterone value below which a man would be considered ]. (Currently, there are no standards as to when to treat women.) Testosterone can be measured as "free" (that is, bioavailable and unbound) or, more commonly, "total" (including the percentage that is chemically bound and unavailable). In the United States, male total testosterone levels below 300&nbsp;ng/dL (10.4&nbsp;nmol/L) from a morning serum sample are generally considered low.<ref name="urlMedlinePlus Medical Encyclopedia: Testosterone">{{cite web | url = http://www.nlm.nih.gov/MEDLINEPLUS/ency/article/003707.htm | title = Testosterone | author = Holt EH, Zieve D | authorlink = | date = March 18, 2008 | work = MedlinePlus Medical Encyclopedia | publisher = U.S. National Library of Medicine | pages = | language = | archiveurl = | archivedate = | quote = | accessdate = July 17, 2009}}</ref> Identification of inadequate testosterone in an aging male by symptoms alone can be difficult.
			]s and ]s of ] ]s like ] have been associated with little or no effect on circulating testosterone levels.{{Citation needed|date=December 2016}}
			===Antiandrogens and estrogens===
	=== Insufficiency ===
			]s like ], ], and ] can block the androgenic and anabolic effects of testosterone.<ref name="WeckerWatts2009">{{cite book | vauthors = Wecker L, Crespo L, Dunaway G, Faingold C, Watts S | title = Brody's Human Pharmacology | url = https://books.google.com/books?id=kfsrz_-OrMQC&pg=PA468 | date = April 1, 2009 | publisher = Elsevier Health Sciences | isbn = 978-0-323-07575-6 | pages = 468–469 | access-date = November 13, 2016 | archive-date = April 14, 2019 | archive-url = https://web.archive.org/web/20190414215026/https://books.google.com/books?id=kfsrz_-OrMQC&pg=PA468 | url-status = live }}</ref><ref name="Becker2001"/><!--Defined in Template:Available forms of testosterone--> ]s can reduce the effects of testosterone by increasing the hepatic production and in turn circulating levels of ] (SHBG), a ] that binds to and occupies androgens like testosterone and DHT, and thereby reducing free concentrations of these androgens.<ref name="Becker2001" /><ref name="WeinKavoussi2015">{{cite book | vauthors = Partin AW, Wein AJ, Kavoussi LR, Peters CA | title = Campbell-Walsh Urology | url = https://books.google.com/books?id=OH_OCgAAQBAJ&pg=PT7207 | date = October 23, 2015 | publisher = Elsevier Health Sciences | isbn = 978-0-323-26374-0 | pages = 7207– | access-date = December 6, 2016 | url-status = live | archive-date = April 14, 2019 | archive-url = https://web.archive.org/web/20190414215011/https://books.google.com/books?id=OH_OCgAAQBAJ&pg=PT7207}}</ref>
	{{Further|Hypogonadism|Androgen deficiency}}
	Testosterone insufficiency (also termed hypotestosteronism or hypotestosteronemia) is an abnormally low testosterone production. It may occur because of testicular dysfunction (]) or hypothalamic-pituitary dysfunction (]) and may be congenital or acquired.<ref>{{cite journal | author = Gould DC, Petty R | title = The male menopause: does it exist?: For: Some men need investigation and testosterone treatment | journal = West. J. Med. | volume = 173 | issue = 2 | pages = 76–8 | date = August 2000 | pmid = 10924412 | pmc = 1070997 | doi = 10.1136/ewjm.173.2.76 | url = }}</ref> An acquired form of hypotestosteronism is the decline in testosterone levels that occurs by ], sometimes called "]" in men, as a comparison to the decline in ] that comes with ] in women. In Western countries, average testosterone levels are receding in men of all ages.<ref name="pmid17062768">{{cite journal | author = Travison TG, Araujo AB, O'Donnell AB, Kupelian V, McKinlay JB | title = A population-level decline in serum testosterone levels in American men | journal = J. Clin. Endocrinol. Metab. | volume = 92 | issue = 1 | pages = 196–202 | date = January 2007 | pmid = 17062768 | doi = 10.1210/jc.2006-1375 }}</ref><ref name="Dindyal_2007">{{cite journal | author = Dindyal S| title=The sperm count has been decreasing steadily for many years in Western industrialised countries: Is there an endocrine basis for this decrease? | journal=The Internet Journal of Urology | volume=2 |issue=1 | pages=1–21 | year=2007 |url=http://www.ispub.com/journal/the-internet-journal-of-urology/volume-2-number-1/the-sperm-count-has-been-decreasing-steadily-for-many-years-in-western-industrialised-countries-is-there-an-endocrine-basis-for-this-decrease.html}}</ref>
	===Women===		==Pharmacology==
	Testosterone supplementation is effective in the short term for ].<ref name=Wie2014/> Its long term safety, however, is unclear.<ref name=Wie2014>{{cite journal | author = Wierman ME, Arlt W, Basson R, Davis SR, Miller KK, Murad MH, Rosner W, Santoro N | title = Androgen therapy in women: a reappraisal: an endocrine society clinical practice guideline. | journal = The Journal of Clinical Endocrinology and Metabolism | volume = 99 | issue = 10 | pages = 3489–510 | date = October 2014 | pmid = 25279570 | doi = 10.1210/jc.2014-2260 }}</ref>
			===Pharmacodynamics===
	Treating low androgen levels with testosterone is not generally recommended in women when it is due to ], ], or following surgical removal of the ovaries.<ref name=Wie2014/> It is also not usually recommended for improving cognition, the risk of heart disease, bone strength or for generalized well being.<ref name=Wie2014/>
			{{See also|Testosterone#Mechanism of action|Anabolic steroid#Pharmacology}}
			{{Relative androgenic to anabolic activity in animals}}
	==Non-medical use==
			Testosterone is a high ] ] for and ] of the ] ] (AR). In addition, testosterone binds to and activates ]s (mARs) such as ] and ]. Testosterone is also potentiated via ] by ] into the more ] androgen DHT in so-called androgenic ]s such as the ], ]s, ], and ]s. In contrast to the case of testosterone, such potentiation occurs to a reduced extent or not at all with most ] AAS (as well as with DHT), and this is primarily responsible for the dissociation of ] and androgenic effects with these agents.<ref name="Kicman2008">{{cite journal | vauthors = Kicman AT | title = Pharmacology of anabolic steroids | journal = British Journal of Pharmacology | volume = 154 | issue = 3 | pages = 502–21 | date = June 2008 | pmid = 18500378 | pmc = 2439524 | doi = 10.1038/bjp.2008.165 }}</ref> In addition to DHT, testosterone is converted at a rate of approximately 0.3% into the ] ] via ].<ref name="BurtisAshwood2012">{{cite book | vauthors = Burtis CA, Ashwood ER, Bruns DE | title = Tietz Textbook of Clinical Chemistry and Molecular Diagnostics | url = https://books.google.com/books?id=BBLRUI4aHhkC&pg=PA1947 | date = October 14, 2012 | publisher = Elsevier Health Sciences | isbn = 978-1-4557-5942-2 | pages = 1947– | url-status = live | archive-url = https://web.archive.org/web/20160522142447/https://books.google.com/books?id=BBLRUI4aHhkC | archive-date = May 22, 2016}}</ref> This occurs in many tissues, especially ], the ], and the ], but primarily in adipose tissue.<ref name="BurtisAshwood2012" /> Testosterone, after conversion into DHT, is also metabolized into 3α-androstanediol, a ] and potent ] of the ], and ], a potent and preferential agonist of the ].<ref name="KohtzFrye2012">{{cite book | vauthors = Kohtz AS, Frye CA | chapter = Dissociating Behavioral, Autonomic, and Neuroendocrine Effects of Androgen Steroids in Animal Models | title = Psychiatric Disorders | series = ] | volume = 829 | pages = 397–431 | year = 2012 | publisher = Springer | pmid = 22231829 | doi = 10.1007/978-1-61779-458-2_26 | isbn = 978-1-61779-457-5 }}</ref> These metabolites, along with estradiol, may be involved in a number of the effects of testosterone in the brain, including its ], ], ]-relieving, ], and ] effects.<ref name="KohtzFrye2012" /> Whereas testosterone produced both anabolic and androgenic effects, despite the lack of clear boundaries between these effects, as there is a great deal of mutual overlap between them,<ref name="pmid25905231">{{cite book | chapter = Androgen Physiology, Pharmacology and Abuse | chapter-url = https://www.ncbi.nlm.nih.gov/books/NBK279000/ | vauthors = Handelsman DJ | title = Endotext | publisher = MDText.com, Inc | date = January 2013 | pmid = 25905231 | access-date = November 11, 2016 | archive-date = March 9, 2021 | archive-url = https://web.archive.org/web/20210309030923/https://www.ncbi.nlm.nih.gov/books/NBK279000/ | url-status = live }}</ref> the relative potency of these effects exerted by testosterone can depend on various factors and is a topic of ongoing research.<ref name="Ceponis-2017">{{cite book | chapter-url=https://link.springer.com/referenceworkentry/10.1007/978-3-319-29456-8_11-1 | doi=10.1007/978-3-319-29456-8_11-1 | chapter=Anabolic and Metabolic Effects of Testosterone and Other Androgens: Direct Effects and Role of Testosterone Metabolic Products | title=Thyroid Diseases | series=Endocrinology | date=2017 | vauthors = Čeponis J, Wang C, Swerdloff S, Liu PY | pages=1–22 | isbn=978-3-319-29195-6 | access-date=April 6, 2024 | archive-date=April 7, 2024 | archive-url=https://web.archive.org/web/20240407084734/https://link.springer.com/referenceworkentry/10.1007/978-3-319-29456-8_11-1 | url-status=live }}</ref><ref name="pmid12017555">{{cite journal |vauthors=Kuhn CM |title=Anabolic steroids |journal=Recent Prog Horm Res |volume=57 |issue= |pages=411–34 |date=2002 |pmid=12017555 |doi=10.1210/rp.57.1.411|doi-access=free }}</ref>
	=== Athletics ===
	Testosterone can be used by an ] in order to improve performance, but it is considered to be a form of ] in most sports. There are several application methods for testosterone, including ]s, ], and implantable pellets. Supplement of the hormone results in lower metabolic production via the ], creating long-term dependence for improved performance level.{{citation needed|date=September 2012}}
			====Effects in the body and brain====
	] (including testosterone) have also been taken to enhance muscle development, strength, or endurance. They do so directly by increasing the muscles' protein synthesis. As a result, muscle fibers become larger and repair faster than the average person's.
			The ARs are expressed widely throughout the body, including in the ], ]s, ], ], ]s, ], ], ], ], ], ], ], ], ]s, ], ], and elsewhere throughout the ].<ref name="NieschlagBehre2010">{{cite book | vauthors = Nieschlag E, Behre HM, Nieschlag S | title = Andrology: Male Reproductive Health and Dysfunction | url = https://books.google.com/books?id=mEgckDNkonUC&pg=PA442 | date = January 13, 2010 | publisher = Springer Science & Business Media | isbn = 978-3-540-78355-8 | pages = 49–54,441–446 | url-status = live | archive-url = https://web.archive.org/web/20160623203518/https://books.google.com/books?id=mEgckDNkonUC | archive-date = June 23, 2016}}</ref><ref name="StraussBarbieri2017">{{cite book |vauthors=Strauss JF, Barbieri RL, Gargiulo AR|title=Yen & Jaffe's Reproductive Endocrinology E-Book: Physiology, Pathophysiology, and Clinical Management |url=https://books.google.com/books?id=67ZEDwAAQBAJ&pg=PA292 |date=December 23, 2017|publisher=Elsevier Health Sciences|isbn=978-0-323-58232-2|pages=292–|access-date=March 31, 2018|archive-date=April 14, 2019|archive-url=https://web.archive.org/web/20190414215014/https://books.google.com/books?id=67ZEDwAAQBAJ&pg=PA292|url-status=live}}</ref> Through activation of the ARs (as well as the mARs), testosterone has many effects, including the following:<ref name="NieschlagBehre2010" /><ref name="NieschlagBehre2012b" />{{Additional citation needed|date=April 2018}}
	After a series of scandals and publicity in the 1980s (such as ] improved performance at the ]), ]s of anabolic steroid use were renewed or strengthened by many sports organizations. Testosterone and other anabolic steroids were designated a "]" by the ] in 1990, with the ''Anabolic Steroid Control Act''.<ref>{{cite web | url = http://www.ussc.gov/USSCsteroidsreport-0306.pdf#search=%22Anabolic%20Steroid%20Control%20Act%20of%201990%22 | title = Anabolic Steroid Control Act| publisher = United States Sentencing Commission|year = 1990}}</ref> Their use is seen as a seriously problematic{{citation needed|date=October 2014}} issue in modern sport, particularly given the lengths to which athletes and professional laboratories go to in trying to conceal such use from sports regulators. Steroid use once again came into the spotlight recently as a result of the ] double murder-suicide in 2007, however, there has been no evidence indicating steroid use as a contributing factor.{{citation needed|date=February 2014}}
			* Promotes growth, function, and maintenance of the ], ], and ] during ] and thereafter
			* Promotes growth and maintenance of ]s, particularly of the ]
			* Causes ] to be ] and decreases overall ]
			* Suppresses ] induced by ]s, but can also still produce ] via excessive conversion into ] if levels are too high
			* Maintains skin health, integrity, appearance, and hydration and slows the rate of aging of the skin, but can also cause ], ], and ]
			* Promotes the growth of ] and ], but can also cause ] and ]
			* Contributes to ] and causes ] at puberty
			* Modulates ], such as the production of ] and many other proteins
			* Increases production of ] in the ]s and thereby stimulates ] production in bone marrow and elevates ]
			* Exerts ] on the ] by suppressing the ] of the ]s ] (FSH) and ] (LH) from the ], thereby inhibiting ]al ] ] as well as ] and ]
			* Regulates the ] and ] via the ], thereby preventing ]es
			* Modulates brain function, with effects on ], ], ], and ], as well as ] and ]
			* Increases ] and ] and causes ]s and ]s
			* Increases the risk of ] and accelerates the progression of prostate cancer
			* Decreases ] and the risk of ]
			===Pharmacokinetics===
	Some female athletes may have naturally higher levels of testosterone than others, and may be asked to consent to a “therapeutic proposal”, either surgery or drugs, to decrease testosteone levels to a level thought acceptable to compete fairly with others.<ref name="NYT-20140411">{{cite news |last1=Karkazis |first1=Katrina |last2=Jordan-Young |first2=Rebecca |title=The Trouble With Too Much T |url=http://www.nytimes.com/2014/04/11/opinion/the-trouble-with-too-much-t.html |date=April 11, 2014 |work=] |accessdate=April 12, 2014 }}</ref>
			{{Main|Pharmacokinetics of testosterone}}
			{{See also|Testosterone (patch)|Androgen ester#Testosterone esters}}
			Testosterone can be taken by a variety of different ].<ref name="BehreNieschlag2012">{{cite book| vauthors = Behre HM, Nieschlag E |chapter=Testosterone preparations for clinical use in males| veditors = Nieschlag E, Behre HM, Nieschlag S |pages=309–335|doi=10.1017/CBO9781139003353.016|title=Testosterone: Action, Deficiency, Substitution|date=July 26, 2012|publisher=Cambridge University Press|isbn=978-1-107-01290-5}}</ref> These include ], ], ], ], ] (]s, ]s, ]es), ] ]), by ] or ] ] (in ] or ]), and as a ].<ref name="BehreNieschlag2012" /> The ] of testosterone, including its ], circulating testosterone levels, ], ], and other parameters, differ by route of administration.<ref name="BehreNieschlag2012" />
	=== Detection of abuse ===
	A number of methods for detecting testosterone use by athletes have been employed, most based on a ]. These include the testosterone/] ratio (normally less than 6), the testosterone/luteinizing hormone ratio and the ] / ] ratio (pharmaceutical testosterone contains less carbon-13 than endogenous testosterone). In some testing programs, an individual's own historical results may serve as a reference interval for interpretation of a suspicious finding. Another approach being investigated is the detection of the administered form of testosterone, usually an ester, in hair.<ref name="pmid19549614">{{cite journal | author = Strahm E, Emery C, Saugy M, Dvorak J, Saudan C | title = Detection of testosterone administration based on the carbon isotope ratio profiling of endogenous steroids: international reference populations of professional soccer players | journal = Br J Sports Med | volume = 43 | issue = 13 | pages = 1041–4 | date = December 2009 | pmid = 19549614 | pmc = 2784500 | doi = 10.1136/bjsm.2009.058669 | url = }}</ref><ref name="pmid20355155">{{cite journal | author = Kicman AT, Cowan DA | title = Subject-based profiling for the detection of testosterone administration in sport | journal = Drug Test Anal | volume = 1 | issue = 1 | pages = 22–4 | date = January 2009 | pmid = 20355155 | doi = 10.1002/dta.14 | url = }}</ref><ref name="pmid19353724">{{cite journal | author = Pozo OJ, Deventer K, Van Eenoo P, Rubens R, Delbeke FT | title = Quantification of testosterone undecanoate in human hair by liquid chromatography-tandem mass spectrometry | journal = Biomed. Chromatogr. | volume = 23 | issue = 8 | pages = 873–80 | date = August 2009 | pmid = 19353724 | doi = 10.1002/bmc.1199 }}</ref><ref name="isbn0-9626523-6-9">{{cite book | author = Baselt RC | title = Disposition of Toxic Drugs & Chemicals in Man | edition = 8th | publisher = Biomedical Publications | location = Foster City, Calif | year = 2008 | origyear = | pages = 1501–1504 | quote = | isbn = 978-0-9626523-7-0 }}</ref>
			==Chemistry==
	== Adverse effects ==
			Testosterone is a ] ] ] and is also known by the chemical name androst-4-en-17β-ol-3-one.<ref name="Elks2014">{{cite book| vauthors = Elks J |title=The Dictionary of Drugs: Chemical Data: Chemical Data, Structures and Bibliographies|url=https://books.google.com/books?id=0vXTBwAAQBAJ&pg=PA641|date=November 14, 2014|publisher=Springer|isbn=978-1-4757-2085-3|pages=641–642|url-status=live|archive-url=https://web.archive.org/web/20170215024945/https://books.google.com/books?id=0vXTBwAAQBAJ|archive-date=February 15, 2017}}</ref> It has a ] between the C4 and C5 positions (making it an ]), a ] ] at the C3 position, and a ] (]) group at the C17β position.<ref name="Elks2014" />
	{{see also|Testosterone#Hormone replacement therapy}}
	Whether or not testosterone therapy in men causes important adverse effects was unclear as of 2010;<ref name=Fer2010>{{cite journal | author = Fernández-Balsells MM, Murad MH, Lane M, Lampropulos JF, Albuquerque F, Mullan RJ, Agrwal N, Elamin MB, Gallegos-Orozco JF, Wang AT, Erwin PJ, Bhasin S, Montori VM | title = Clinical review 1: Adverse effects of testosterone therapy in adult men: a systematic review and meta-analysis. | journal = The Journal of Clinical Endocrinology and Metabolism | volume = 95 | issue = 6 | pages = 2560–75 | date = June 2010 | pmid = 20525906 | doi = 10.1210/jc.2009-2575 }}</ref> however, as of September 2014, such therapy has been under review for appropriateness and safety by the ] due to the "potential for adverse cardiovascular outcomes".<ref name="NYT-20140917" /><ref name="CNN-20140905" /><ref name="FDA-20140903" />
	===Cardiovascular disease===		===Derivatives===
			{{See also|Androgen ester#Testosterone esters|List of androgens/anabolic steroids}}
	On January 31, 2014, reports of strokes, heart attacks, and deaths in men taking FDA-approved testosterone-replacement led the Food and Drug Administration to announce that it would be investigating this issue.<ref>http://www.fda.gov/downloads/Drugs/DrugSafety/UCM383909.pdf</ref> The FDA is requiring warnings in the drug labeling of all approved testosterone products regarding ] and ].<ref>{{cite web |author=Staff |title=FDA adding general warning to testosterone products about potential for venous blood clots|url=http://www.fda.gov/Drugs/DrugSafety/ucm401746.htm|website=]|accessdate=October 9, 2014|date=June 19, 2014}}</ref>
			Testosterone esters are ] at the C17β position with a ] ] ] ] of varying ] length.<ref name="JamesonGroot2015">{{cite book|vauthors=Jameson JL, De Groot LJ|title=Endocrinology: Adult and Pediatric|url=https://books.google.com/books?id=xmLeBgAAQBAJ&pg=PA2387|date=February 25, 2015|publisher=Elsevier Health Sciences|isbn=978-0-323-32195-2|pages=2387–|access-date=November 18, 2016|archive-date=April 14, 2019|archive-url=https://web.archive.org/web/20190414214952/https://books.google.com/books?id=xmLeBgAAQBAJ&pg=PA2387|url-status=live}}</ref> Major testosterone esters include ], ], ], and ].<ref name="Becker2001" /><ref name="Elks2014" /><ref name="ChappleSteers2011">{{cite book|vauthors=Chapple CR, Steers WD|title=Practical Urology: Essential Principles and Practice: Essential Principles and Practice|url=https://books.google.com/books?id=A9m8TkdCUqEC&pg=PA228|date=May 10, 2011|publisher=Springer Science & Business Media|isbn=978-1-84882-034-0|pages=228–|access-date=November 18, 2016|archive-date=April 14, 2019|archive-url=https://web.archive.org/web/20190414215041/https://books.google.com/books?id=A9m8TkdCUqEC&pg=PA228|url-status=live}}</ref> A C17β ] ] of testosterone, ], has also been marketed, although it is little known and is used very rarely or no longer.<ref name="Elks2014" /> Another C17β ether prodrug of testosterone, ], also exists but was never marketed, and is notable in that it is orally active.<ref name="Elks2014" /> In addition to ester and ether prodrugs, ]s or ]s of testosterone, such as ] (DHEA), ], and ], exist as well, and convert into testosterone to variable extents upon oral ingestion.<ref name="GregoryTravis2015">{{cite book|vauthors=Gregory HM, Travis TN|title=Essentials of Strength Training and Conditioning|edition=4th|url=https://books.google.com/books?id=bfuXCgAAQBAJ&pg=PA233|date=September 23, 2015|publisher=Human Kinetics|isbn=978-1-4925-0162-6|pages=229, 233|access-date=November 18, 2016|archive-date=February 17, 2018|archive-url=https://web.archive.org/web/20180217202709/https://books.google.com/books?id=bfuXCgAAQBAJ&pg=PA233|url-status=live}}</ref> Unlike testosterone ester and ether prodrugs however, these prohormones are only weakly androgenic/anabolic.<ref name="GregoryTravis2015" />
	Adverse effects of testosterone supplementation may include increased cardiovascular events (including ]s and ]s) and ]s based on three peer-reviewed studies involving men taking testosterone-replacement.<ref>{{cite journal | author = Finkle WD, Greenland S, Ridgeway GK, Adams JL, Frasco MA, Cook MB, Fraumeni JF, Hoover RN | title = Increased Risk of Non-fatal Myocardial Infarction Following Testosterone Therapy Prescription in Men | journal = ] | volume = 9 | issue = 1 | pages = e85805 | date = January 2014 | pmid = 24489673 | pmc = 3905977 | doi = 10.1371/journal.pone.0085805 | url = http://testosteronedruglawyers.com/wp-content/uploads/2014/03/Study-by-Finkle.pdf }}</ref> In addition, an increase of 30% in deaths and heart attacks in older men has been reported.<ref name="pmid24193080">{{cite journal | author = Vigen R, O'Donnell CI, Barón AE, Grunwald GK, Maddox TM, Bradley SM, Barqawi A, Woning G, Wierman ME, Plomondon ME, Rumsfeld JS, Ho PM | title = Association of testosterone therapy with mortality, myocardial infarction, and stroke in men with low testosterone levels | journal = ] | volume = 310 | issue = 17 | pages = 1829–36 | year = 2013 | pmid = 24193080 | doi = 10.1001/jama.2013.280386 }}</ref> Due to an increased incidence of adverse cardiovascular events compared to a ], a Testosterone in Older Men with Mobility Limitations (TOM) trial (a ] randomized trial) was halted early by the ].<ref>{{cite journal | author = Basaria S, Coviello AD, Travison TG, Storer TW, Farwell WR, Jette AM, Eder R, Tennstedt S, Ulloor J, Zhang A, Choong K, Lakshman KM, Mazer NA, Miciek R, Krasnoff J, Elmi A, Knapp PE, Brooks B, Appleman E, Aggarwal S, Bhasin G, Hede-Brierley L, Bhatia A, Collins L, LeBrasseur N, Fiore LD, Bhasin S | title = Adverse Events Associated with Testosterone Administration | journal = ] | volume = 363 | issue = 2 | pages = 109–22 | date = July 2010 | pmid = 20592293 | pmc = 3440621 | doi = 10.1056/NEJMoa1000485 }}</ref> On January 31, 2014, reports of ]s, ]s, and ]s in men taking ]-approved testosterone-replacement led the ] (]) to announce that it would be investigating the issue.<ref name="FDA-20140131">{{cite web |author=Staff |title=FDA evaluating risk of stroke, heart attack and death with FDA-approved testosterone products |url=http://www.fda.gov/downloads/Drugs/DrugSafety/UCM383909.pdf |publisher=] |date=January 31, 2014 |format=] |accessdate=September 17, 2014 }}</ref> Later, in September 2014, the ] announced, as a result of the "potential for adverse cardiovascular outcomes", a review of the appropriateness and safety of Testosterone Replacement Therapy (TRT).<ref name="NYT-20140917">{{cite news |last=Tavernise |first=Sabrina |title=F.D.A. Panel Backs Limits on Testosterone Drugs |url=http://www.nytimes.com/2014/09/18/health/testosterone-drugs-fda.html |date=September 17, 2014 |work=] |accessdate=September 18, 2014 }}</ref><ref name="CNN-20140905">{{cite news |author=Staff |title=FDA Panel To Review Testosterone Therapy Appropriateness and Safety |url=http://ireport.cnn.com/docs/DOC-1167887 |date=September 5, 2014 |work=] |accessdate=September 14, 2014 }}</ref><ref name="FDA-20140903">{{cite web |author=Staff |title=Joint Meeting for Bone, Reproductive and Urologic Drugs Advisory Committee (BRUDAC) and the Drug Safety And Risk Management Advisory Committee (DSARM AC) – FDA background documents for the discussion of two major issues in testosterone replacement therapy (TRT): 1. The appropriate indicated population for TRT, and 2. The potential for adverse cardiovascular outcomes associated with use of TRT |url=http://www.fda.gov/downloads/AdvisoryCommittees/CommitteesMeetingMaterials/Drugs/ReproductiveHealthDrugsAdvisoryCommittee/UCM412536.pdf |date=September 17, 2014 |work=] |format=] |accessdate=September 14, 2014 }}</ref>
			All synthetic AAS are ]s of testosterone.<ref name="GregoryTravis2015" /> Prominent examples include ] (19-nortestosterone), ] (17α-methyl-δ<sup>1</sup>-testosterone), and ] (a 17α-alkylated derivative of DHT). Unlike testosterone, AAS that are ], like metandienone and stanozolol, are orally active. This is due to ] of C17β-position metabolism during the first-pass through the liver. In contrast, most AAS that are not 17α-alkylated, like nandrolone, are not active orally, and must instead be administered via intramuscular injection. This is almost always in ester form; for instance, in the case of nandrolone, as ] or ].
	Up to the year 2010, studies had not shown any effect on the risk of death, ] or ];<ref name=Fer2010/><ref>{{cite journal | author = Haddad RM, Kennedy CC, Caples SM, Tracz MJ, Boloña ER, Sideras K, Uraga MV, Erwin PJ, Montori VM | title = Testosterone and cardiovascular risk in men: a systematic review and meta-analysis of randomized placebo-controlled trials. | journal = Mayo Clinic proceedings. Mayo Clinic | volume = 82 | issue = 1 | pages = 29–39 | date = January 2007 | pmid = 17285783 | doi = 10.4065/82.1.29 }}</ref> more recent studies, however, do raise concerns.<ref>{{cite web|title=Testosterone Products: Drug Safety Communication – FDA Investigating Risk of Cardiovascular Events|url=http://www.fda.gov/Safety/MedWatch/SafetyInformation/SafetyAlertsforHumanMedicalProducts/ucm384225.htm|work=FDA|accessdate=February 3, 2014|date=January 31, 2014}}</ref> A 2013 study, published in the Journal of the American Medical Association, reported "the use of testosterone therapy was significantly associated with increased risk of adverse outcomes." The study began after a previous, randomized, clinical trial of testosterone therapy in men was stopped prematurely "due to adverse cardiovascular events raising concerns about testosterone therapy safety."<ref name=vigen2013>{{cite journal | author = Vigen R, O'Donnell CI, Barón AE, Grunwald GK, Maddox TM, Bradley SM, Barqawi A, Woning G, Wierman ME, Plomondon ME, Rumsfeld JS, Ho PM | title = Association of testosterone therapy with mortality, myocardial infarction, and stroke in men with low testosterone levels. | journal = Journal of the American Medical Association | volume = 310 | issue = 17 | pages = 1829–36 | date = November 6, 2013 | pmid = 24193080 | doi = 10.1001/jama.2013.280386 | url = http://jama.jamanetwork.com/article.aspx?articleid=1764051 | accessdate = June 16, 2014 }}</ref>
			{{Structural properties of major testosterone esters}}
	===Cancer===
	Testosterone in the presence of a slow-growing cancer is assumed to increase its growth rate. However, the association between testosterone supplementation and the development of prostate cancer is unproven.<ref name="pmid19863857">{{cite journal | author = Rhoden EL, Averbeck MA | title = Testosterone therapy and prostate carcinoma | journal = Curr Urol Rep | volume = 10 | issue = 6 | pages = 453–9 | date = November 2009 | pmid = 19863857 | doi = 10.1007/s11934-009-0072-1 }}</ref> Nevertheless, physicians are cautioned about the cancer risk associated with testosterone supplementation.<ref name="pmid16006887">{{cite journal | author = Gaylis FD, Lin DW, Ignatoff JM, Amling CL, Tutrone RF, Cosgrove DJ | title = Prostate cancer in men using testosterone supplementation | journal = J. Urol. | volume = 174 | issue = 2 | pages = 534–8; discussion 538 | date = August 2005 | pmid = 16006887 | doi = 10.1097/01.ju.0000165166.36280.60 }}</ref>
			==History==
	Ethnic groups have different rates of ].<ref name=Cal2010/> Differences in sex hormones, including testosterone, have been suggested as an explanation for these differences.<ref name=Cal2010>{{cite journal | author = Calistro Alvarado L | title = Population differences in the testosterone levels of young men are associated with prostate cancer disparities in older men | journal = Am. J. Hum. Biol. | volume = 22 | issue = 4 | pages = 449–55 | year = 2010 | pmid = 20087895 | doi = 10.1002/ajhb.21016 }}</ref> This apparent paradox can be resolved by noting that prostate cancer is very common. In autopsies, 80% of 80-year-old men have prostate cancer.<ref name="pmid15495199">{{cite journal | author = Bostwick DG, Burke HB, Djakiew D, Euling S, Ho SM, Landolph J, Morrison H, Sonawane B, Shifflett T, Waters DJ, Timms B | title = Human prostate cancer risk factors | journal = Cancer | volume = 101 | issue = 10 Suppl | pages = 2371–490 | date = November 2004 | pmid = 15495199 | doi = 10.1002/cncr.20408 | laysource = Mercer University School of Medicine | layurl = http://library.med.utah.edu/WebPath/TUTORIAL/PROSTATE/PROSTATE.html }}</ref>
			{{See also|Testosterone#History|Anabolic steroid#History}}
			Testosterone was first isolated and ] in 1935.<ref name="M.D.2002">{{cite book | vauthors = Taylor WN | title = Anabolic Steroids and the Athlete | edition = 2nd | url = https://books.google.com/books?id=OGcQ0Tp2AFcC&pg=PA180 | date = January 16, 2002 | publisher = McFarland | isbn = 978-0-7864-1128-3 | pages = 180– | access-date = November 13, 2016 | archive-date = July 29, 2018 | archive-url = https://web.archive.org/web/20180729102024/https://books.google.com/books?id=OGcQ0Tp2AFcC&pg=PA180 | url-status = live }}</ref> Shortly thereafter, in 1937, testosterone first became commercially available as a ] in the form of ]s and then in ester form for intramuscular injection as the relatively short-acting testosterone propionate.<ref name="Llewellyn2011">{{cite book|vauthors=Llewellyn W|title=Anabolics|url=https://books.google.com/books?id=afKLA-6wW0oC&pg=PT385|year=2011|publisher=Molecular Nutrition Llc|isbn=978-0-9828280-1-4|pages=385–394, 413, 426, 607, 666|access-date=December 18, 2017|archive-date=April 14, 2019|archive-url=https://web.archive.org/web/20190414215102/https://books.google.com/books?id=afKLA-6wW0oC|url-status=live}}</ref><ref name="NieschlagBehre2012b" /><ref name="Hoberman2005">{{cite book | vauthors = Hoberman J | title = Testosterone Dreams: Rejuvenation, Aphrodisia, Doping | url = https://archive.org/details/testosteronedrea00hobe | url-access = registration | date = February 21, 2005 |publisher=University of California Press|isbn=978-0-520-93978-3|pages=–}}</ref> ], one of the first synthetic AAS and orally active androgens, was introduced in 1935, but was associated with hepatotoxicity and eventually became largely medically obsolete.<ref name="Hoberman2005" /> In the mid-1950s, the longer-acting testosterone esters ] and ] were introduced.<ref name="Hoberman2005" /> They largely superseded testosterone propionate and became the major testosterone esters used medically for over half a century.<ref name="Hoberman2005" /> In the 1970s, ] was introduced for oral use in Europe,<ref name="Hoberman2005" /> although intramuscular testosterone undecanoate had already been in use in China for several years.<ref name="MundyFitzpatrick2010">{{cite book|vauthors=Mundy AR, Fitzpatrick J, Neal DE, George NJ|title=The Scientific Basis of Urology|url=https://books.google.com/books?id=h6HSBQAAQBAJ&pg=PA294|date=July 26, 2010|publisher=CRC Press|isbn=978-1-84184-749-8|pages=294–|access-date=November 18, 2016|archive-date=April 14, 2019|archive-url=https://web.archive.org/web/20190414215011/https://books.google.com/books?id=h6HSBQAAQBAJ&pg=PA294|url-status=live}}</ref> Intramuscular testosterone undecanoate was not introduced in Europe and the United States until much later (in the early to mid 2000s and 2014, respectively).<ref name="MelmedPolonsky2015" /><ref>{{cite journal | vauthors = ((Adis R&D Profile)) | s2cid = 43349541 | year = 2004 | title = Testosterone Undecanoate—Schering AG | journal = Drugs | volume = 5 | issue = 6| pages = 368–369 | doi=10.2165/00126839-200405060-00012| pmid = 15563244 }}</ref>
	===Other===
	Other adverse effects of testosterone supplementation may include increased ] (which may require ] in order to treat), exacerbation of ] and acceleration of pre-existing ] growth in individuals having undergone androgen deprivation.{{citation needed|date=September 2014}} Other adverse effects may include minor side-effects such as acne and oily skin as well as significant hair loss and/or thinning of the hair which may be prevented with ] inhibitors ordinarily used for the treatment of ] such as ] or ].{{citation needed|date=September 2014}} Exogenous testosterone may also cause suppression of ], leading to infertility.<ref name="pmid1977002">{{cite journal | title = Contraceptive efficacy of testosterone-induced azoospermia in normal men. World Health Organization Task Force on methods for the regulation of male fertility | journal = Lancet | volume = 336 | issue = 8721 | pages = 955–9 | date = October 1990 | pmid = 1977002 | doi = 10.1016/0140-6736(90)92416-F | url = }}</ref> It does increase ] levels and decrease ] levels but it is not clear if these changes are meaningful.<ref name=Fer2010/>
			The history of testosterone as a medication has been reviewed.<ref name="NieschlagNieschlag2017">{{cite book| vauthors = Nieschlag E, Nieschlag S |chapter=The History of Testosterone and the Testes: From Antiquity to Modern Times |title=Testosterone|year=2017|pages=1–19|publisher=Springer |doi=10.1007/978-3-319-46086-4_1|isbn=978-3-319-46084-0}}</ref><ref name="NieschlagNieschlag2019">{{cite journal | vauthors = Nieschlag E, Nieschlag S | title = ENDOCRINE HISTORY: The history of discovery, synthesis and development of testosterone for clinical use | journal = European Journal of Endocrinology | volume = 180 | issue = 6 | pages = R201–R212 | date = June 2019 | pmid = 30959485 | doi = 10.1530/EJE-19-0071 | doi-access = free }}</ref><ref name="NieschlagNieschlag2014">{{cite journal | vauthors = Nieschlag E, Nieschlag S | title = Testosterone deficiency: a historical perspective | journal = Asian Journal of Andrology | volume = 16 | issue = 2 | pages = 161–8 | year = 2014 | pmid = 24435052 | pmc = 3955324 | doi = 10.4103/1008-682X.122358 | doi-access = free }}</ref><ref name="MorgentalerTraish2018">{{cite journal | vauthors = Morgentaler A, Traish A | title = The History of Testosterone and the Evolution of its Therapeutic Potential | journal = Sexual Medicine Reviews | volume = 8 | issue = 2 | pages = 286–296 | date = April 2020 | pmid = 29661690 | doi = 10.1016/j.sxmr.2018.03.002 | s2cid = 4903551 }}</ref>
	===Pregnancy and breast feeding===
	Testosterone is contraindicated in pregnancy and not recommended during breastfeeding.<ref>{{cite web|title=Testosterone Pregnancy and Breastfeeding Warnings|url=http://www.drugs.com/pregnancy/testosterone.html|accessdate=February 1, 2014}}</ref>
			==Society and culture==
	== Biochemistry ==
			{{See also|Androgen replacement therapy#Society and culture|Anabolic steroid#Society and culture}}
	=== Biosynthesis ===		===Usage===
			In the US in the 2000s, companies and figures in the popular media have heavily marketed notions of "andropause" as something parallel to ]; these notions have been rejected by the medical community.<ref name=NHSChoices>{{cite web|title=Male Menopause|url=http://www.nhs.uk/conditions/Male-menopause/Pages/Introduction.aspx|website=www.nhs.uk|publisher=NHS Choices|date=April 8, 2016|access-date=October 7, 2016|url-status=live |archive-url=https://web.archive.org/web/20161009181414/http://www.nhs.uk/conditions/Male-menopause/Pages/Introduction.aspx|archive-date=October 9, 2016}}</ref><ref>{{cite web | vauthors = Gorski D | title = "Low T": The triumph of marketing over science « Science-Based Medicine | url = https://www.sciencebasedmedicine.org/low-t-the-triumph-of-marketing-over-science/ | publisher = Science-Based Medicine | date = November 25, 2013 | url-status = live | archive-url = https://web.archive.org/web/20160911022624/https://www.sciencebasedmedicine.org/low-t-the-triumph-of-marketing-over-science/ | archive-date = September 11, 2016}}</ref> Additionally, advertising from drug companies selling testosterone and human growth hormone, as well as ] companies selling all kinds of "boosters" for aging men, have emphasized the "need" of middle-aged or ageing men for testosterone.<ref name=PerlsEd2015/> There is a medical condition called ]; according to Thomas Perls and David J. Handelsman, writing in a 2015 editorial in the '']'', it appears that this condition is ] and ].<ref name=PerlsEd2015>{{cite journal | vauthors = Perls T, Handelsman DJ | title = Disease mongering of age-associated declines in testosterone and growth hormone levels | journal = Journal of the American Geriatrics Society | volume = 63 | issue = 4 | pages = 809–11 | date = April 2015 | pmid = 25809947 | doi = 10.1111/jgs.13391 | s2cid = 328558 | doi-access = free }}</ref> Perls and Handelsman note that in the US, "sales of testosterone increased from $324 million in 2002 to $2 billion in 2012, and the number of testosterone doses prescribed climbed from 100 million in 2007 to half a billion in 2012, not including the additional contributions from compounding pharmacies, Internet, and direct-to-patient clinic sales."<ref name=PerlsEd2015/>
	], showing testosterone near bottom.]]
	Like other ] hormones, testosterone is derived from ] (see figure to the left).<ref name="pmid1307739">{{cite journal | author = Waterman MR, Keeney DS | title = Genes involved in androgen biosynthesis and the male phenotype | journal = Horm. Res. | volume = 38 | issue = 5–6 | pages = 217–21 | year = 1992 | pmid = 1307739 | doi = 10.1159/000182546 | url = }}</ref> The first step in the ] involves the oxidative cleavage of the sidechain of cholesterol by ], a ] ] oxidase with the loss of six carbon atoms to give ]. In the next step, two additional carbon atoms are removed by the ] enzyme in the ] to yield a variety of C<sub>19</sub> steroids.<ref name="pmid3535074">{{cite journal | author = Zuber MX, Simpson ER, Waterman MR | title = Expression of bovine 17 alpha-hydroxylase cytochrome P-450 cDNA in nonsteroidogenic (COS 1) cells | journal = Science | volume = 234 | issue = 4781 | pages = 1258–61 | date = December 1986 | pmid = 3535074 | doi = 10.1126/science.3535074 | url = | bibcode = 1986Sci...234.1258Z }}</ref> In addition, the 3-hydroxyl group is oxidized by ] to produce ]. In the final and rate limiting step, the C-17 keto group androstenedione is reduced by ] to yield testosterone.
			===Generic names===
	The largest amounts of testosterone (>95%) are produced by the ] in men.<ref name="Mooradian_ 1987"/> It is also synthesized in far smaller quantities in women by the ] of the ], by the ], as well as by the ] of the ] and even ]<ref name="pmid15507105">{{cite journal | author = Zouboulis CC, Degitz K | title = Androgen action on human skin – from basic research to clinical significance | journal = Exp. Dermatol. | volume = 13 Suppl 4 | issue = s4| pages = 5–10 | year = 2004 | pmid = 15507105 | doi = 10.1111/j.1600-0625.2004.00255.x }}</ref> in both sexes. In the ], testosterone is produced by the ]s.<ref name="pmid58744">{{cite journal | author = Brooks RV | title = Androgens | journal = Clin Endocrinol Metab | volume = 4 | issue = 3 | pages = 503–20 | date = November 1975 | pmid = 58744 | doi = 10.1016/S0300-595X(75)80045-4 | url = }}</ref> The male generative glands also contain ]s, which require testosterone for ]. Like most hormones, testosterone is supplied to target tissues in the blood where much of it is transported bound to a specific ], ] (SHBG).
			''Testosterone'' is the ] of testosterone in English and Italian and the {{abbrlink|INN|International Nonproprietary Name}}, {{abbrlink|USAN|United States Adopted Name}}, {{abbrlink|USP|United States Pharmacopeia}}, {{abbrlink|BAN|British Approved Name|BAN}}, and {{abbrlink|DCIT|Denominazione Comune Italiana}} of the drug, while ''testostérone'' is its French name and the {{abbrlink|DCF|Dénomination Commune Française}}.<ref name="Elks2014" /><ref name="Drugs.com" /><ref name="IndexNominum2000">{{cite book|title=Index Nominum 2000: International Drug Directory|url=https://books.google.com/books?id=5GpcTQD_L2oC|date=January 2000|publisher=Taylor & Francis|isbn=978-3-88763-075-1|access-date=December 2, 2016|archive-date=October 21, 2021|archive-url=https://web.archive.org/web/20211021002502/https://books.google.com/books?id=5GpcTQD_L2oC|url-status=live}}</ref> It is also referred to in ] as ''testosteronum'', in Spanish and Portuguese as ''testosterona'', and in German, ], and Russian and other ]s as ''testosteron''.<ref name="Drugs.com" /><ref name="IndexNominum2000" /> The ] of testosterone is ''тестостерон''.<ref name="Мюллер2016">{{cite book|author=Владимир Мюллер|title=Англо-русский словарь. Русско-английский словарь. 250 000 слов|url=https://books.google.com/books?id=rOP6CwAAQBAJ&pg=PA643|date=April 15, 2016|publisher=ЛитРес|isbn=978-5-457-98308-3|pages=643–|access-date=December 2, 2016|archive-date=April 14, 2019|archive-url=https://web.archive.org/web/20190414214954/https://books.google.com/books?id=rOP6CwAAQBAJ&pg=PA643|url-status=live}}</ref>
	=== Regulation ===		===Brand names===
			]
	]
	In males, testosterone is synthesized primarily in ]. The number of Leydig cells in turn is regulated by ] (LH) and ] (FSH). In addition, the amount of testosterone produced by existing Leydig cells is under the control of LH, which regulates the expression of ].<ref name="isbn0-9627422-7-9">{{cite book | author = Payne AH, O'Shaughnessy P | authorlink = | editor = Payne AH, Hardy MP, Russell LD | others = | title = Leydig Cell | edition = | language = | publisher = Cache River Press | location = Vienna | year = 1996 | origyear = | pages = 260–285 | quote = | isbn = 0-9627422-7-9 | oclc = | doi = | url = | chapter = Structure, function, and regulation of steroidogenic enzymes in the Leydig cell }}</ref>
			Testosterone is marketed under a large number of brand names throughout the world.<ref name="Drugs.com">{{cite web |title=Testosterone - International |url=https://www.drugs.com/international/testosterone.html |publisher=Drugs.com |access-date=November 12, 2016 |url-status=live |archive-url=https://web.archive.org/web/20161113175707/https://www.drugs.com/international/testosterone.html |archive-date=November 13, 2016}}</ref> Major brand names of testosterone and/or its esters include Andriol, Androderm, AndroGel, Axiron, Delatestryl, Depo-Testosterone, ], Nebido, ], Primoteston, ], Testim, TestoGel, TestoPatch, Testoviron, and Tostran.<ref name="Becker2001" /><ref name="Kicman2008" /><ref name="Drugs.com" />
	The amount of testosterone synthesized is regulated by the ] (see figure to the right).<ref name="pmid1377467">{{cite journal | author = Swerdloff RS, Wang C, Bhasin S | title = Developments in the control of testicular function | journal = Baillieres Clin. Endocrinol. Metab. | volume = 6 | issue = 2 | pages = 451–83 | date = April 1992 | pmid = 1377467 | doi = 10.1016/S0950-351X(05)80158-2 | url = }}</ref> When testosterone levels are low, gonadotropin-releasing hormone (]) is released by the ], which in turn stimulates the ] to release FSH and LH. These latter two hormones stimulate the testis to synthesize testosterone. Finally, increasing levels of testosterone through a negative ] loop act on the hypothalamus and pituitary to inhibit the release of GnRH and FSH/LH, respectively.
			===Availability===
	Factors affecting testosterone levels include:
	* Weight loss may result in an increase in testosterone levels. Fat cells synthesize the enzyme aromatase, which converts testosterone, the male sex hormone, into estradiol, the female sex hormone.<ref name="pmid21849026">{{cite journal | author = Håkonsen LB, Thulstrup AM, Aggerholm AS, Olsen J, Bonde JP, Andersen CY, Bungum M, Ernst EH, Hansen ML, Ernst EH, Ramlau-Hansen CH | title = Does weight loss improve semen quality and reproductive hormones? Results from a cohort of severely obese men | journal = Reprod Health | volume = 8 | issue = 1| page = 24 | year = 2011 | pmid = 21849026 | pmc = 3177768 | doi = 10.1186/1742-4755-8-24 }}</ref>
	* The secosteroid ] in levels of 400–1000&nbsp;]/d (10–25&nbsp;µg/d) raises testosterone levels.<ref name="pmid21154195">{{cite journal | author = Pilz S, Frisch S, Koertke H, Kuhn J, Dreier J, Obermayer-Pietsch B, Wehr E, Zittermann A | title = Effect of vitamin D supplementation on testosterone levels in men | journal = Horm. Metab. Res. | volume = 43 | issue = 3 | pages = 223–5 | date = March 2011 | pmid = 21154195 | doi = 10.1055/s-0030-1269854 }}</ref>
	* ] deficiency lowers testosterone levels<ref name="pmid8875519">{{cite journal | author = Prasad AS, Mantzoros CS, Beck FW, Hess JW, Brewer GJ | title = Zinc status and serum testosterone levels of healthy adults | journal = Nutrition | volume = 12 | issue = 5 | pages = 344–8 | date = May 1996 | pmid = 8875519 | doi = 10.1016/S0899-9007(96)80058-X | url = }}</ref> but over supplementation has no effect on serum testosterone.<ref name="pmid17882141">{{cite journal | author = Koehler K, Parr MK, Geyer H, Mester J, Schänzer W | title = Serum testosterone and urinary excretion of steroid hormone metabolites after administration of a high-dose zinc supplement | journal = Eur J Clin Nutr | volume = 63 | issue = 1 | pages = 65–70 | date = January 2009 | pmid = 17882141 | doi = 10.1038/sj.ejcn.1602899 | url = }}</ref>
	* Dominance challenges can, in some cases, stimulate increased testosterone release in men.<ref name="pmid10603287">{{cite journal | author = Schultheiss OC, Campbell KL, McClelland DC | title = Implicit power motivation moderates men's testosterone responses to imagined and real dominance success | journal = Horm Behav | volume = 36 | issue = 3 | pages = 234–41 | date = December 1999 | pmid = 10603287 | doi = 10.1006/hbeh.1999.1542 | url = }}</ref>
	* Aging reduces testosterone release.<ref name="pmid16339924">{{cite journal | author = Liu PY, Pincus SM, Takahashi PY, Roebuck PD, Iranmanesh A, Keenan DM, Veldhuis JD | title = Aging attenuates both the regularity and joint synchrony of LH and testosterone secretion in normal men: analyses via a model of graded GnRH receptor blockade | journal = Am. J. Physiol. Endocrinol. Metab. | volume = 290 | issue = 1 | pages = E34–E41 | date = January 2006 | pmid = 16339924 | doi = 10.1152/ajpendo.00227.2005 | url = }}</ref>
	* ]
	* Sleep (]) increases nocturnal testosterone levels.<ref name="pmid18519168">{{cite journal | author = Andersen ML, Tufik S | title = The effects of testosterone on sleep and sleep-disordered breathing in men: its bidirectional interaction with erectile function | journal = Sleep Med Rev | volume = 12 | issue = 5 | pages = 365–79 | date = October 2008 | pmid = 18519168 | doi = 10.1016/j.smrv.2007.12.003 | url = http://www.sono.org.br/pdf/2008_Andersen_Sleep_Med_Rev.pdf }}</ref>
	* ] increases testosterone levels,<ref name="url_Marin">{{cite journal | author = Marin DP, Figueira AJ Junior, Pinto LG | year = 2006| title = One session of resistance training may increase serum testosterone and triiodetironine in young men| url = http://journals.lww.com/acsm-msse/Fulltext/2006/05001/One_Session_of_Resistance_Training_May_Increase.2108.aspx| journal = Medicine & Science in Sports & Exercise | volume = 38 | issue = 5 | page = S285 | doi =10.1249/00005768-200605001-01235 }}</ref> however, in older men, that increase can be avoided by protein ingestion.<ref name="pmid18455389">{{cite journal | author = Hulmi JJ, Ahtiainen JP, Selänne H, Volek JS, Häkkinen K, Kovanen V, Mero AA | title = Androgen receptors and testosterone in men—effects of protein ingestion, resistance exercise and fiber type | journal = J. Steroid Biochem. Mol. Biol. | volume = 110 | issue = 1–2 | pages = 130–7 | date = May 2008 | pmid = 18455389 | doi = 10.1016/j.jsbmb.2008.03.030 | url = }}</ref>
	*]. The active ingredient in licorice root, ] has been linked to small, clinically non-significant decreases in testosterone levels.<ref name="pmid11716893">{{cite journal | author = Josephs RA, Guinn JS, Harper ML, Askari F | title = Liquorice consumption and salivary testosterone concentrations | journal = Lancet | volume = 358 | issue = 9293 | pages = 1613–4 | date = November 2001 | pmid = 11716893 | doi = 10.1016/S0140-6736(01)06664-8 | url = }}</ref> In contrast, a more recent study found that licorice administration produced a substantial testosterone decrease in a small, female-only sample.<ref name="pmid15579328">{{cite journal | author = Armanini D, Mattarello MJ, Fiore C, Bonanni G, Scaroni C, Sartorato P, Palermo M | title = Licorice reduces serum testosterone in healthy women | journal = Steroids | volume = 69 | issue = 11–12 | pages = 763–6 | year = 2004 | pmid = 15579328 | doi = 10.1016/j.steroids.2004.09.005 | url = }}</ref>
	* Natural or man-made ] including ] tea reduce testosterone levels.<ref name="pmid17310494">{{cite journal | author = Akdoğan M, Tamer MN, Cüre E, Cüre MC, Köroğlu BK, Delibaş N | title = Effect of spearmint (Mentha spicata Labiatae) teas on androgen levels in women with hirsutism | journal = Phytother Res | volume = 21 | issue = 5 | pages = 444–7 | date = May 2007 | pmid = 17310494 | doi = 10.1002/ptr.2074 | url = }}</ref><ref name="pmid18804513">{{cite journal | author = Kumar V, Kural MR, Pereira BM, Roy P | title = Spearmint induced hypothalamic oxidative stress and testicular anti-androgenicity in male rats&nbsp;– altered levels of gene expression, enzymes and hormones | journal = Food Chem. Toxicol. | volume = 46 | issue = 12 | pages = 3563–70 | date = December 2008 | pmid = 18804513 | doi = 10.1016/j.fct.2008.08.027 | url = }}</ref><ref name="pmid19585478">{{cite journal | author = Grant P | title = Spearmint herbal tea has significant anti-androgen effects in polycystic ovarian syndrome. A randomized controlled trial | journal = Phytother Res | volume = 24 | issue = 2 | pages = 186–8 | date = February 2010 | pmid = 19585478 | doi = 10.1002/ptr.2900 | url = }}</ref>
	* Posing in high-power nonverbal displays through open, expansive postures can increase testosterone levels.<ref name="pmid20855902">{{cite journal | author = Carney DR, Cuddy AJ, Yap AJ | title = Power posing: brief nonverbal displays affect neuroendocrine levels and risk tolerance | journal = Psychol Sci. | volume = 21 | issue = 10 | pages = 1363–1368 | date = October 2010 | pmid = 20855902 | doi = 10.1177/0956797610383437 | accessdate = March 31, 2014 }}</ref>
	=== Metabolism ===		====United States====
			{{See also|List of androgens/anabolic steroids available in the United States#Testosterone and esters}}
	Approximately 7% of testosterone is reduced to 5α-] (DHT) by the cytochrome P<sub>450</sub> enzyme ],<ref name="pmid8092979">{{cite journal | author = Randall VA | title = Role of 5 alpha-reductase in health and disease | journal = Baillieres Clin. Endocrinol. Metab. | volume = 8 | issue = 2 | pages = 405–31 | date = April 1994 | pmid = 8092979 | doi = 10.1016/S0950-351X(05)80259-9 | url = }}</ref> an enzyme highly expressed in male sex organs and hair follicles.<ref name="Mooradian_ 1987"/> Approximately 0.3% of testosterone is converted into estradiol by ] (CYP19A1)<ref name="pmid12428207">{{cite journal | author = Meinhardt U, Mullis PE | title = The essential role of the aromatase/p450arom | journal = Semin. Reprod. Med. | volume = 20 | issue = 3 | pages = 277–84 | date = August 2002 | pmid = 12428207 | doi = 10.1055/s-2002-35374 | url = }}</ref> an enzyme expressed in the brain, liver, and adipose tissues.<ref name="Mooradian_ 1987"/>
			{{As of|2016|11}}, unmodified (non-esterified) testosterone is available in the United States in the following formulations:<ref name="Drugs@FDA"/><!--Defined in Template:Available forms of testosterone-->
	DHT is a more potent form of testosterone while estradiol has completely different activities (feminization) compared to testosterone (masculinization). Also, testosterone and DHT may be deactivated or cleared by enzymes that hydroxylate at the 6, 7, 15 or 16 positions.<ref name="isbn0-3870-8012-0">{{cite book | author = Trager L | authorlink = | editor = | others = | title = Steroidhormone: Biosynthese, Stoffwechsel, Wirkung | edition = | language = German | publisher = Springer-Verlag | location = | year = 1977 | origyear = | page = 349 | quote = | isbn = 0-387-08012-0 | oclc = | doi = | url = | accessdate = }}</ref>
			* ]: AndroGel, Fortesta, Testim, Testosterone (generic)
			* Topical solutions: Axiron, Testosterone (generic)
			* Transdermal patches: Androderm, Testoderm (discontinued), Testoderm TTS (discontinued), Testosterone (generic)
			* ] gels: Natesto
			* Buccal tablets: Striant
			* Pellet implants: Testopel
			And the following ester prodrugs of testosterone are available in the United States in oil solutions for intramuscular injection:<ref name="Drugs@FDA" />
	== Mechanism of action ==
			* ]: Depo-Testosterone, Testosterone Cypionate (generic)
	The effects of testosterone in humans and other ] occur by way of two main mechanisms: by activation of the ] (directly or as DHT), and by conversion to ] and activation of certain ]s.<ref name="pmid18406296">{{cite journal | author = Hiipakka RA, Liao S | title = Molecular mechanism of androgen action | journal = Trends Endocrinol. Metab. | volume = 9 | issue = 8 | pages = 317–24 | date = October 1998 | pmid = 18406296 | doi = 10.1016/S1043-2760(98)00081-2 | url = }}</ref><ref name="pmid11511858">{{cite journal | author = McPhaul MJ, Young M | title = Complexities of androgen action | journal = J. Am. Acad. Dermatol. | volume = 45 | issue = 3 Suppl | pages = S87–94 | date = September 2001 | pmid = 11511858 | doi = 10.1067/mjd.2001.117429 | url = }}</ref>
			* ]: Delatestryl, Xyosted (auto-injector), Testosterone Enanthate (generic)
			* ]: Testosterone Propionate (generic)
			* ]: Aveed
			Unmodified testosterone was also formerly available for intramuscular injection but was discontinued.<ref name="Drugs@FDA" />
	Free testosterone (T) is transported into the ] of target ] ], where it can bind to the ], or can be reduced to 5α-] (DHT) by the cytoplasmic enzyme ]. DHT binds to the same androgen receptor even more strongly than testosterone, so that its androgenic potency is about 5 times that of T.<ref name="pmid3762019">{{cite journal | author = Breiner M, Romalo G, Schweikert HU | title = Inhibition of androgen receptor binding by natural and synthetic steroids in cultured human genital skin fibroblasts | journal = Klin. Wochenschr. | volume = 64 | issue = 16 | pages = 732–7 | date = August 1986 | pmid = 3762019 | doi = 10.1007/BF01734339 | url = }}</ref> The T-receptor or DHT-receptor complex undergoes a structural change that allows it to move into the ] and bind directly to specific ] sequences of the ] DNA. The areas of binding are called ]s (HREs), and influence transcriptional activity of certain ]s, producing the androgen effects.
			Testosterone cypionate and testosterone enanthate were formerly available in combination with ] and ], respectively, under the brand names Depo-Testadiol and Ditate-DS, respectively, as oil solutions for intramuscular injection, but these formulations have been discontinued.<ref name="Drugs@FDA" />
	Androgen receptors occur in many different vertebrate body system tissues, and both males and females respond similarly to similar levels. Greatly differing amounts of testosterone prenatally, at puberty, and throughout life account for a share of biological ] between males and females.
			Unlike in Europe, Canada, and much of the rest of the world, oral testosterone undecanoate is not available in the United States.<ref name="Drugs@FDA" />
	The bones and the brain are two important tissues in humans where the primary effect of testosterone is by way of ] to ]. In the bones, estradiol accelerates ossification of cartilage into bone, leading to closure of the ] and conclusion of growth. In the central nervous system, testosterone is aromatized to estradiol. Estradiol rather than testosterone serves as the most important feedback signal to the hypothalamus (especially affecting ] secretion).{{Citation needed|date=January 2011}} In many ]s, prenatal or perinatal "masculinization" of the ] areas of the brain by estradiol derived from testosterone programs later male sexual behavior.{{Citation needed|date=January 2011}}
			<ref name="MorleyBerg1999">{{cite book | vauthors = Morley JE | chapter = Testosterone | veditors = Morley JE, van den Berg L | title = Endocrinology of Aging | series = Disease-a-Month | chapter-url = https://books.google.com/books?id=hGD0BwAAQBAJ&pg=PA141 | date = November 5, 1999 | volume = 34 | issue = 7 | publisher = Springer Science & Business Media | isbn = 978-1-59259-715-4 | pages = 141– | doi = 10.1016/s0011-5029(98)90024-4 | pmid = 3044718 | access-date = November 15, 2016 | archive-date = April 14, 2019 | archive-url = https://web.archive.org/web/20190414215126/https://books.google.com/books?id=hGD0BwAAQBAJ&pg=PA141 | url-status = live }}</ref><ref name="BagatellBremner2003-misc">{{cite book|vauthors=Bagatell C, Bremner WJ|title=Androgens in Health and Disease|url=https://books.google.com/books?id=vDcBCAAAQBAJ&pg=PA259|date=May 27, 2003|publisher=Springer Science & Business Media|isbn=978-1-59259-388-0|access-date=November 18, 2016|archive-date=April 14, 2019|archive-url=https://web.archive.org/web/20190414215125/https://books.google.com/books?id=vDcBCAAAQBAJ&pg=PA259|url-status=live}}</ref>
	== Synthetic analogs ==
	A number of synthetic analogs of testosterone have been developed with improved ] and ] relative to testosterone. Many of these analogs have an ] group introduced at the C-17 position in order to prevent ] and hence improve oral bioavailability. These are the so-called "17-aa" (17-alkyl androgen) family of androgens such as ] and ].
	== Related drugs ==		====Canada====
			{{as of|2016|11}}, testosterone is available in Canada in the form of topical gels (AndroGel, Testim), topical solutions (Axiron), transdermal patches (Androderm), and intranasal gels (Natesto).<ref name="DPD@HealthCanada">{{cite web |title=Drug Product Database - Health Canada |publisher=Health Canada |url=http://www.hc-sc.gc.ca/dhp-mps/prodpharma/databasdon/index-eng.php |access-date=November 13, 2016 |url-status=live |archive-url=https://web.archive.org/web/20161119200516/http://www.hc-sc.gc.ca/dhp-mps/prodpharma/databasdon/index-eng.php |archive-date=November 19, 2016 |date=March 18, 2010 }}</ref> Testosterone cypionate (Depo-Testosterone, Testosterone Cypionate (generic)), testosterone enanthate (Delatestryl, PMS-Testosterone Enanthate), and testosterone propionate (Testosterone Propionate (generic)) are available as oil solutions for intramuscular injection and testosterone undecanoate (Andriol, PMS-Testosterone, Taro-Testosterone) is available in the form of oral capsules.<ref name="DPD@HealthCanada" /> Testosterone buccal tablets and pellet implants do not appear to be available in Canada.<ref name="DPD@HealthCanada" />
	Some drugs indirectly target testosterone as a way of treating certain conditions. For example, ]s such as ] inhibit the conversion of testosterone into ] (DHT), a metabolite more potent than testosterone.<ref name="pmid15853706">{{cite journal | author = Bratoeff E, Cabeza M, Ramirez E, Heuze Y, Flores E | title = Recent advances in the chemistry and pharmacological activity of new steroidal antiandrogens and 5 alpha-reductase inhibitors | journal = Curr. Med. Chem. | volume = 12 | issue = 8 | pages = 927–43 | year = 2005 | pmid = 15853706 | doi = 10.2174/0929867053507306 | url = }}</ref> These 5-alpha-reductase inhibitors have been used to treat various conditions associated with androgens, such as ] (]), ], ] (BPH), and ].<ref name="pmid15853706"/> In contrast, ] bind to ] in the ], blocking the release of ] (LH) and ] (FSH) from the pituitary.<ref name="pmid17237842">{{cite journal | author = Engel JB, Schally AV | title = Drug Insight: clinical use of agonists and antagonists of luteinizing-hormone-releasing hormone | journal = Nat Clin Pract Endocrinol Metab | volume = 3 | issue = 2 | pages = 157–67 | date = February 2007 | pmid = 17237842 | doi = 10.1038/ncpendmet0399 | url = }}</ref> In men, the reduction in LH subsequently leads to rapid suppression of testosterone release from the ]. GnRH antagonists have been used for the treatment of prostate cancer.
			====Other countries====
	== Routes of administration ==
			Testosterone and/or its esters are widely available in countries throughout the world in a variety of formulations.<ref name="Drugs.com" />
	]
	There are many ] for testosterone. Forms of testosterone for human administration currently available include injectable (such as testosterone ] or testosterone ] in oil),<ref name="urlTestosterone Information from Drugs.com">{{cite web | url = http://www.drugs.com/testosterone.html | title = Testosterone Information | authorlink = | work = | publisher = Drugs.com | pages = |language = | archiveurl = | archivedate = | quote = | accessdate = }}</ref> oral, ],<ref name="urlStriant Official FDA information, side effects and uses.">{{cite web | url =http://www.drugs.com/pro/striant.html | title = Striant Official FDA information, side effects and uses |authorlink = | work = | publisher = Drugs.com | pages = | language = | archiveurl = |archivedate = | quote = | accessdate = }}</ref> transdermal skin patches, transdermal creams, gels,<ref name="urlAndroGel Official FDA information, side effects and uses.">{{cite web | url =http://www.drugs.com/pro/androgel.html | title = AndroGel Official FDA information, side effects and uses |authorlink = | work = | publisher = Drugs.com | pages = | language = | archiveurl = |archivedate = | quote = | accessdate = }}</ref><ref name="urlTestim (patches and gel) medical facts from Drugs.com">{{cite web | url = http://www.drugs.com/mtm/testim-patches-and-gel.html | title = Testim (patches and gel) medical facts | authorlink = | work = | publisher = Drugs.com }}</ref> and implantable pellets.<ref name="urlwww.slatepharma.com">{{cite web | url =http://www.slatepharma.com | title = Testopel Pellets | publisher = www.slatepharma.com | pages = | language = | archiveurl = | archivedate = | quote = | accessdate = }}</ref> Roll-on methods and nasal sprays are currently under development.
	== History ==		===Legal status===
			{{See also|Anabolic steroid#Legal status}}
	A ] action was linked to circulating blood fractions&nbsp;– now understood to be a family of androgenic hormones&nbsp;– in the early work on castration and testicular transplantation in fowl by ] (1803–1861).<ref name="Berthold_1849">{{cite journal |author = Berthold AA | title = Transplantation der Hoden | trans_title = Transplantation of testis | language = German | journal = Arch. Anat. Physiol. Wissensch. |volume = 16 |issue = |pages = 42–6 | year = 1849 | pmid = | doi= | url =}}</ref> Research on the action of testosterone received a brief boost in 1889, when the Harvard professor ] (1817–1894), then in Paris, self-injected subcutaneously a "rejuvenating elixir" consisting of an extract of dog and guinea pig testicle. He reported in ''The Lancet'' that his vigor and feeling of well-being were markedly restored but the effects were transient,<ref name="Brown-Sequard_1889">{{cite journal |author = Brown-Sequard CE | title = The effects produced on man by subcutaneous injections of liquid obtained from the testicles of animals |language = | journal = Lancet |volume = 2 | issue = 3438|page = 105| year = 1889 | doi = 10.1016/S0140-6736(00)64118-1| url =}}</ref> and Brown-Séquard's hopes for the compound were dashed. Suffering the ridicule of his colleagues, he abandoned his work on the mechanisms and effects of androgens in human beings.
			Testosterone and its esters, along with other AAS, are ] ]s in many countries throughout the world. In the United States, they are ] drugs under the ], in Canada, they are ] drugs under the ], and in the United Kingdom, they are ] drugs under the ].<ref name="FFFLM2006b">{{cite book|vauthors=Karch SB|title=Drug Abuse Handbook, Second Edition|url=https://books.google.com/books?id=ZjrMBQAAQBAJ&pg=PA30|date=December 21, 2006|publisher=CRC Press|isbn=978-1-4200-0346-8|pages=30–|access-date=November 11, 2017|archive-date=April 14, 2019|archive-url=https://web.archive.org/web/20190414215105/https://books.google.com/books?id=ZjrMBQAAQBAJ&pg=PA30|url-status=live}}</ref><ref name="LilleySnyder2016">{{cite book |vauthors=Lilley LL, Snyder JS, Collins SR |title=Pharmacology for Canadian Health Care Practice |url=https://books.google.com/books?id=dNgoDwAAQBAJ&pg=PA50 |date=August 5, 2016 |publisher=Elsevier Health Sciences |isbn=978-1-77172-066-3 |pages=50– |access-date=November 11, 2017 |archive-date=April 14, 2019 |archive-url=https://web.archive.org/web/20190414214954/https://books.google.com/books?id=dNgoDwAAQBAJ&pg=PA50 |url-status=live }}</ref>
	In 1927, the University of Chicago's Professor of Physiologic Chemistry, Fred C. Koch, established easy access to a large source of bovine testicles — the Chicago stockyards — and recruited students willing to endure the tedious work of extracting their isolates. In that year, Koch and his student, Lemuel McGee, derived 20&nbsp;mg of a substance from a supply of 40 pounds of bovine testicles that, when administered to castrated roosters, pigs and rats, remasculinized them.<ref name="Gallagher_Koch_1929">{{cite journal | author = Gallagher TF, Koch FC | title = The testicular hormone |journal = J. Biol. Chem. | volume = 84 | issue = 2 | pages = 495–500 |date=November 1929 | pmid = | doi = | url = }}</ref> The group of Ernst Laqueur at the University of Amsterdam purified testosterone from bovine testicles in a similar manner in 1934, but isolation of the hormone from animal tissues in amounts permitting serious study in humans was not feasible until three European pharmaceutical giants—] (Berlin, Germany), ] (Oss, Netherlands) and ] (Basel, Switzerland)—began full-scale steroid research and development programs in the 1930s.
	]
	The Organon group in the Netherlands were the first to isolate the hormone, identified in a May 1935 paper "On Crystalline Male Hormone from Testicles (Testosterone)".<ref name="David_1935">{{cite journal | author = David KG., Dingemanse E, Freud J. Laqueur E | title = Über krystallinisches mannliches Hormon aus Hoden (Testosteron) wirksamer als aus harn oder aus Cholesterin bereitetes Androsteron | trans_title = On crystalline male hormone from testicles (testosterone) effective as from urine or from cholesterol | language = German | journal = Hoppe Seylers Z Physiol Chem | volume = 233 | issue = 5–6| page = 281 |date=May 1935 | pmid = | doi = 10.1515/bchm2.1935.233.5-6.281| url = }}</ref> They named the hormone ''testosterone'', from the ] of ''testicle'' and '']'', and the ] of '']''. The structure was worked out by Schering's ].<ref name="Butenandt_1935a">{{cite journal | author = Butenandt A, Hanisch G | title = Umwandlung des Dehydroandrosterons in Androstendiol und Testosterone; ein Weg zur Darstellung des Testosterons aus Cholestrin | trans_title = About Testosterone. Conversion of Dehydro-androsterons into androstendiol and testosterone; a way for the structure assignment of testosterone from cholestrol | language = German | journal = Hoppe Seylers Z Physiol Chem | volume = 237 | issue = 2| page = 89 | year = 1935 | pmid = | doi = 10.1515/bchm2.1935.237.1-3.89| url = }}</ref><ref name="pmid11176375">{{cite journal | author = Freeman ER, Bloom DA, McGuire EJ | title = A brief history of testosterone | journal = J. Urol. | volume = 165 | issue = 2 | pages = 371–3 | date = February 2001 | pmid = 11176375 | doi = 10.1097/00005392-200102000-00004 | url = }}</ref>
			===Litigation===
	The ] of testosterone from cholesterol was achieved in August that year by Butenandt and Hanisch.<ref name="Butenandt_1935b">{{cite journal | author = Butenandt A, Hanisch G | title = Uber die Umwandlung des Dehydroandrosterons in Androstenol-(17)-one-(3) (Testosterone); um Weg zur Darstellung des Testosterons auf Cholesterin (Vorlauf Mitteilung). | journal = Chemische Berichte | year = 1935 | volume = 68 | pages = 1859–1862 | language = German }}</ref> Only a week later, the Ciba group in Zurich, ] (1887–1976) and A. Wettstein, published their synthesis of testosterone.<ref name="Ruzicka_1935">{{cite journal | author = Ruzicka L, Wettstein A | title = Uber die kristallinische Herstellung des Testikelhormons, Testosteron (Androsten-3-ol-17-ol) | journal = Helvetica Chimica Acta | year = 1935 | volume = 18 | pages = 1264–1275 | language = German | doi=10.1002/hlca.193501801176}}</ref> These independent partial syntheses of testosterone from a cholesterol base earned both Butenandt and Ruzicka the joint 1939 ].<ref name="pmid11176375"/><ref name="pmid7817189">{{cite journal | author = Hoberman JM, Yesalis CE | title = The history of synthetic testosterone | journal = Sci. Am. | volume = 272 | issue = 2 | pages = 76–81 | date = February 1995 | pmid = 7817189 | doi = 10.1038/scientificamerican0295-76 | url = }}</ref> Testosterone was identified as 17β-hydroxyandrost-4-en-3-one (C<sub>19</sub>H<sub>28</sub>O<sub>2</sub>), a solid polycyclic alcohol with a hydroxyl group at the 17th carbon atom. This also made it obvious that additional modifications on the synthesized testosterone could be made, i.e., esterification and alkylation.
			{{As of|2014}}, a number of lawsuits are underway against manufacturers of testosterone, alleging a significantly increased rate of stroke and heart attack in elderly men who use testosterone supplementation.<ref name=Harris2014>{{cite news | vauthors = Harris A | title = Abbott Labs Sued by Five Men Claiming Androgel Injuries | url = https://www.bloomberg.com/news/2014-02-05/abbott-labs-sued-by-five-men-claiming-androgel-injuries.html | website = Bloomberg.com | date = February 5, 2014 | publisher = Bloomberg, L.P. | access-date = June 16, 2014 | url-status = live | archive-url = https://web.archive.org/web/20140714195657/http://www.bloomberg.com/news/2014-02-05/abbott-labs-sued-by-five-men-claiming-androgel-injuries.html | archive-date = July 14, 2014}}</ref>{{update inline|date=January 2020}}
			===Doping in sports===
	The partial synthesis in the 1930s of abundant, potent testosterone esters permitted the characterization of the hormone's effects, so that Kochakian and Murlin (1936) were able to show that testosterone raised nitrogen retention (a mechanism central to anabolism) in the dog, after which Allan Kenyon's group<ref name=" Kenyon _1940">{{cite journal | author = Kenyon AT, Knowlton K, Sandiford I, Koch FC, Lotwin,G | title = A comparative study of the metabolic effects of testosterone propionate in normal men and women and in eunuchoidism | journal = Endocrinology | volume = 26| issue = 1 | pages = 26–45 |date=February 1940| doi = 10.1210/Endo-26-1-26 | url = }}</ref> was able to demonstrate both anabolic and androgenic effects of testosterone propionate in eunuchoidal men, boys, and women. The period of the early 1930s to the 1950s has been called "The Golden Age of Steroid Chemistry",<ref name="pmid10443899">{{cite journal | author = Schwarz S, Onken D, Schubert A | title = The steroid story of Jenapharm: from the late 1940s to the early 1970s | journal = Steroids | volume = 64 | issue = 7 | pages = 439–45 | date = July 1999 | pmid = 10443899 | doi = 10.1016/S0039-128X(99)00003-3 | url = http://www.ingentaconnect.com/content/els/0039128x/1999/00000064/00000007/art00003 }}</ref> and work during this period progressed quickly. Research in this golden age proved that this newly synthesized compound—testosterone—or rather family of compounds (for many derivatives were developed from 1940 to 1960), was a potent multiplier of muscle, strength, and well-being.<ref name = "de Kruif_1945" >{{cite book | author = de Kruif P | title = The Male Hormone | publisher = Harcourt, Brace| location = New York |year = 1945 |pages = | isbn = | oclc = | doi = }}</ref>
			{{See also|List of doping in sport cases#Testosterone and esters}}
			There are many known cases of ] with testosterone and its esters by ] ]s.
	==Society and culture==
	A number of lawsuits are currently underway against testosterone manufacturers, alleging a significantly increased rate of stroke and heart attack in elderly men who use testosterone supplements.<ref name=Harris2014>{{cite web|last1=Harris|first1=Andrew|title=Abbott Labs Sued by Five Men Claiming Androgel Injuries|url=http://www.bloomberg.com/news/2014-02-05/abbott-labs-sued-by-five-men-claiming-androgel-injuries.html|website=Bloomberg.com|publisher=Bloomberg, L.P.|accessdate=June 16, 2014}}</ref>
	== References ==		==Research==
	{{Reflist|30em}}
			===Depression===
			Testosterone has been used to treat depression in men who are of middle age with low testosterone. However, a 2014 review showed no benefit on the mood of the men with normal levels of testosterone or on the mood of the older men with low testosterone.<ref name="pmid24501728">{{cite journal | vauthors = Amanatkar HR, Chibnall JT, Seo BW, Manepalli JN, Grossberg GT | title = Impact of exogenous testosterone on mood: a systematic review and meta-analysis of randomized placebo-controlled trials | journal = Annals of Clinical Psychiatry | volume = 26 | issue = 1 | pages = 19–32 | date = Feb 2014 | pmid = 24501728 | url = http://www.aacp.com/pdf%2F0214%2F0214ACP%5FAmanatkar%2Epdf }}{{Dead link|date=July 2020 |bot=InternetArchiveBot |fix-attempted=yes }}</ref> Conversely, a 2009 review found that testosterone had an antidepressant effect in men with depression, especially those with hypogonadism, HIV/AIDS, and in the elderly.<ref name="pmid19625884">{{cite journal | vauthors = Zarrouf FA, Artz S, Griffith J, Sirbu C, Kommor M | s2cid = 205423837 | title = Testosterone and depression: systematic review and meta-analysis | journal = J Psychiatr Pract | volume = 15 | issue = 4 | pages = 289–305 | date = July 2009 | pmid = 19625884 | doi = 10.1097/01.pra.0000358315.88931.fc }}</ref>
			===Heart failure===
			Testosterone replacement can significantly improve ], ] and reduce ]s in men with ] (CHF). Over the 3 to 6-month course of the studies reviewed, testosterone therapy appeared safe and generally effective, and (ruling out prostate cancer) the authors found no justification to absolutely restrict its use in men with CHF.<ref name=Wang2016>{{cite journal | vauthors = Wang W, Jiang T, Li C, Chen J, Cao K, Qi LW, Li P, Zhu W, Zhu B, Chen Y | title = Will testosterone replacement therapy become a new treatment of chronic heart failure? A review based on 8 clinical trials | journal = Journal of Thoracic Disease | volume = 8 | issue = 5 | pages = E269–77 | date = May 2016 | pmid = 27162680 | pmc = 4842839 | doi = 10.21037/jtd.2016.03.39 | doi-access = free }}</ref> A similar 2012 review also found increased exercise capacity and reasoned the benefits generlizable to women.<ref name=Toma2012>{{cite journal | vauthors = Toma M, McAlister FA, Coglianese EE, Vidi V, Vasaiwala S, Bakal JA, Armstrong PW, Ezekowitz JA | title = Testosterone Supplementation in Heart Failure: A Meta-Analysis | journal = Circulation: Heart Failure | volume = 5 | issue = 3 | pages = 315–21 | date = May 2012 | pmid = 22511747 | doi = 10.1161/CIRCHEARTFAILURE.111.965632 | doi-access = free }}</ref> However, both reviews advocate larger, longer term, ]s.<ref name=Wang2016/><ref name=Toma2012/>
			===Male contraception===
			Testosterone, as esters such as testosterone undecanoate or testosterone buciclate, has been studied and promoted as a ] analogous to ] in women. Otherwise considered an adverse effect of testosterone, reduced spermatogenesis can be further suppressed with the addition of a ] such as ] or ], improving the contraceptive effect.<ref>{{cite journal | vauthors = Wang C, Festin MP, Swerdloff RS | title = Male Hormonal Contraception: Where Are We Now? | journal = Current Obstetrics and Gynecology Reports | volume = 5 | pages = 38–47 | date = 2016 | pmid = 26949570 | pmc = 4762912 | doi = 10.1007/s13669-016-0140-8 }}</ref><ref>{{cite journal | vauthors = Chao JH, Page ST | title = The current state of male hormonal contraception | journal = Pharmacology & Therapeutics | volume = 163 | pages = 109–17 | date = July 2016 | pmid = 27016468 | doi = 10.1016/j.pharmthera.2016.03.012 }}</ref>
			===Anorgasmia===
			{{See also|List of investigational sexual dysfunction drugs}}
			Testosterone is under development in a low-dose intranasal formulation for the treatment of ] in women.<ref name="AdisInsight">{{cite web |url=http://adisinsight.springer.com/drugs/800029680 |title=Testosterone intranasal (low-dose) |access-date=September 5, 2017 |url-status=live |archive-url=https://web.archive.org/web/20170906035736/http://adisinsight.springer.com/drugs/800029680 |archive-date=September 6, 2017}}</ref>
			===Miscellaneous===
			Testosterone therapy may improve the management of ].<ref name="pmid18772488">{{cite journal | vauthors = Traish AM, Saad F, Guay A | title = The dark side of testosterone deficiency: II. Type 2 diabetes and insulin resistance | journal = Journal of Andrology | volume = 30 | issue = 1 | pages = 23–32 | year = 2009 | pmid = 18772488 | doi = 10.2164/jandrol.108.005751 }}</ref> Low testosterone has been associated with the development of ].<ref name="pmid16785599">{{cite journal | vauthors = Pike CJ, Rosario ER, Nguyen TV | s2cid = 13852805 | title = Androgens, aging, and Alzheimer's disease | journal = Endocrine | volume = 29 | issue = 2 | pages = 233–41 | date = Apr 2006 | pmid = 16785599 | doi = 10.1385/ENDO:29:2:233 }}</ref><ref name="pmid15383512">{{cite journal | vauthors = Rosario ER, Chang L, Stanczyk FZ, Pike CJ | title = Age-related testosterone depletion and the development of Alzheimer disease | journal = JAMA | volume = 292 | issue = 12 | pages = 1431–32 | date = Sep 2004 | pmid = 15383512 | doi = 10.1001/jama.292.12.1431-b }}</ref>
			Topical androgens like testosterone have been used and studied in the treatment of ] in women.<ref name="pmid12626029">{{cite journal | vauthors = Gruber CJ, Wieser F, Gruber IM, Ferlitsch K, Gruber DM, Huber JC | s2cid = 37424524 | title = Current concepts in aesthetic endocrinology | journal = Gynecol. Endocrinol. | volume = 16 | issue = 6 | pages = 431–41 | date = December 2002 | pmid = 12626029 | doi = 10.1080/gye.16.6.431.441 }}</ref>
			==References==
			{{Reflist}}
			==Further reading==
			{{refbegin}}
			* {{cite book|vauthors=Nieschlag E, Behre JM, Nieschlag S|title=Andrology: Male Reproductive Health and Dysfunction|url=https://books.google.com/books?id=mEgckDNkonUC|date=January 13, 2010|publisher=Springer Science & Business Media|isbn=978-3-540-78355-8|access-date=November 13, 2016|archive-date=June 23, 2016|archive-url=https://web.archive.org/web/20160623203518/https://books.google.com/books?id=mEgckDNkonUC|url-status=live}}
			* {{cite book|vauthors=Nieschlag E, Behre HM, Nieschlag S|title=Testosterone: Action, Deficiency, Substitution|url=https://books.google.com/books?id=MkrAPaQ4wJkC|date=July 26, 2012|publisher=Cambridge University Press|isbn=978-1-107-01290-5|access-date=July 31, 2018|archive-date=April 14, 2019|archive-url=https://web.archive.org/web/20190414215108/https://books.google.com/books?id=MkrAPaQ4wJkC|url-status=live}}
			* {{cite book|vauthors=Hohl A|title=Testosterone: From Basic to Clinical Aspects|url=https://books.google.com/books?id=Et6TDgAAQBAJ|date=March 30, 2017|publisher=Springer|isbn=978-3-319-46086-4|access-date=July 31, 2018|archive-date=April 14, 2019|archive-url=https://web.archive.org/web/20190414215052/https://books.google.com/books?id=Et6TDgAAQBAJ|url-status=live}}
			* {{cite journal | vauthors = Nieschlag E, Nieschlag S | title = Testosterone deficiency: a historical perspective | journal = Asian J. Androl. | volume = 16 | issue = 2 | pages = 161–8 | date = 2014 | pmid = 24435052 | pmc = 3955324 | doi = 10.4103/1008-682X.122358 | doi-access = free }}
			* {{cite book|vauthors=Llewellyn W|title=Anabolics|url=https://books.google.com/books?id=afKLA-6wW0oC|year=2011|publisher=Molecular Nutrition Llc|isbn=978-0-9828280-1-4|access-date=November 18, 2016|archive-date=April 14, 2021|archive-url=https://web.archive.org/web/20210414083125/https://books.google.com/books?id=afKLA-6wW0oC|url-status=live}}
			* {{cite journal | vauthors = Shoskes JJ, Wilson MK, Spinner ML | title = Pharmacology of testosterone replacement therapy preparations | journal = Translational Andrology and Urology | volume = 5 | issue = 6 | pages = 834–843 | date = December 2016 | pmid = 28078214 | pmc = 5182226 | doi = 10.21037/tau.2016.07.10 | doi-access = free }}
			* {{cite journal | vauthors = Celec P, Ostatníková D, Hodosy J | title = On the effects of testosterone on brain behavioral functions | journal = Frontiers in Neuroscience | volume = 9 | pages = 12 | date = February 2015 | pmid = 25741229 | pmc = 4330791 | doi = 10.3389/fnins.2015.00012 | doi-access = free }}
			{{refend}}
	==External links==		==External links==
			* {{cite web | title=Testosterone Transdermal Patch | website=MedlinePlus | url=https://medlineplus.gov/druginfo/meds/a601118.html }}
	*
			* {{cite web | title=Testosterone Buccal | website=MedlinePlus | url=https://medlineplus.gov/druginfo/meds/a603034.html }}
	* in the ]
			* {{cite web | title=Testosterone Topical | website=MedlinePlus | url=https://medlineplus.gov/druginfo/meds/a605020.html }}
	*
			* {{cite web | title=Testosterone Injection | website=MedlinePlus | url=https://medlineplus.gov/druginfo/meds/a614041.html }}
			* {{cite web | title=Testosterone Nasal Gel | website=MedlinePlus | url=https://medlineplus.gov/druginfo/meds/a615025.html }}
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			]<!--As an appetite stimulant-->
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			]<!--Via metabolism into estradiol and androstanediols-->
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			]<!--Via metabolism into 3α-androstanediol-->
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