Editing Testosterone (section)

=== Health effects ===
Testosterone does not appear to increase the risk of developing [[prostate cancer]]. 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 book | vauthors = Morgentaler A, Schulman C | chapter = Testosterone and prostate safety | volume = 37 | pages = 197–203 | year = 2009 | pmid = 19011298 | doi = 10.1159/000176054 | isbn = 978-3-8055-8622-1 | series = Frontiers of Hormone Research | title = Advances in the Management of Testosterone Deficiency }}</ref><ref>{{cite journal | vauthors = Rhoden EL, Averbeck MA, Teloken PE | title = Androgen replacement in men undergoing treatment for prostate cancer | journal = The Journal of Sexual Medicine | volume = 5 | issue = 9 | pages = 2202–08 | date = Sep 2008 | pmid = 18638000 | doi = 10.1111/j.1743-6109.2008.00925.x }}</ref><ref>{{cite journal | vauthors = Morgentaler A, Traish AM | title = Shifting the paradigm of testosterone and prostate cancer: the saturation model and the limits of androgen-dependent growth | journal = European Urology | volume = 55 | issue = 2 | pages = 310–20 | date = Feb 2009 | pmid = 18838208 | doi = 10.1016/j.eururo.2008.09.024 }}</ref>

Conflicting results have been obtained concerning the importance of [[Testosterone and cardiovascular system|testosterone in maintaining cardiovascular health]].<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="pmid19464009">{{cite journal | vauthors = 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 = Dec 2009 | pmid = 19464009 | doi = 10.1016/j.atherosclerosis.2009.04.016 }}</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 improved glycemic control.<ref name="pmid18488876">{{cite journal | vauthors = Stanworth RD, Jones TH | title = Testosterone for the aging male; current evidence and recommended practice | journal = Clinical Interventions in Aging | volume = 3 | issue = 1 | pages = 25–44 | year = 2008 | pmid = 18488876 | pmc = 2544367 | doi =  10.2147/CIA.S190 | doi-access = free }}</ref>

High androgen levels are associated with [[menstrual cycle]] irregularities in both clinical populations and healthy women.{{better source needed|date=July 2021}}<ref name="pmid17039468">{{cite journal | vauthors = Van Anders SM, Watson NV | title = Menstrual cycle irregularities are associated with testosterone levels in healthy premenopausal women | journal = American Journal of Human Biology | volume = 18 | issue = 6 | pages = 841–44 | year = 2006 | pmid = 17039468 | doi = 10.1002/ajhb.20555 | url = https://deepblue.lib.umich.edu/bitstream/2027.42/83925/1/menstrual_cycle_irregularities_are_associated_with_testosterone_levels_in_healthy_premenopausal_women.pdf | hdl = 2027.42/83925 | s2cid = 32023452 | hdl-access = free | access-date = August 29, 2019 | archive-date = February 13, 2021 | archive-url = https://web.archive.org/web/20210213011139/https://deepblue.lib.umich.edu/bitstream/handle/2027.42/83925/menstrual_cycle_irregularities_are_associated_with_testosterone_levels_in_healthy_premenopausal_women.pdf;jsessionid=AC61249B183224834C48B1216A6F6FC6?sequence=1 | url-status = live }}</ref> There also can be effects in unusual hair growth, [[acne]], weight gain, infertility, and sometimes even scalp hair loss. These effects are seen largely in women with polycystic ovary syndrome ([[PCOS]]). For women with PCOS, hormones like [[birth control pills]] can be used to help lessen the effects of this increased level of testosterone.<ref>{{cite web |author= |date=June 6, 2020 |title=Polycystic Ovary Syndrome (PCOS) |url=https://studentaffairs.psu.edu/health-wellness/healthcare-and-medical-services/health-information-resources/polycystic-ovary#:~:text=In%20PCOS%2C%20the%20ovaries%20do,hair%20loss%20from%20the%20scalp. |access-date=May 14, 2024 |website=Penn State Student Affairs |publisher=Penn State University 2022}}</ref>

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 [[dementia]] of the Alzheimer's type,<ref name="pmid16785599">{{cite journal |vauthors=Pike CJ, Rosario ER, Nguyen TV |date=Apr 2006 |title=Androgens, aging, and Alzheimer's disease |journal=Endocrine |volume=29 |issue=2 |pages=233–41 |doi=10.1385/ENDO:29:2:233 |pmid=16785599 |s2cid=13852805}}</ref><ref name="pmid15383512">{{cite journal |vauthors=Rosario ER, Chang L, Stanczyk FZ, Pike CJ |date=Sep 2004 |title=Age-related testosterone depletion and the development of Alzheimer disease |journal=JAMA |volume=292 |issue=12 |pages=1431–32 |doi=10.1001/jama.292.12.1431-b |pmid=15383512}}</ref><ref name="pmid15582279">{{cite journal |vauthors=Hogervorst E, Bandelow S, Combrinck M, Smith AD |year=2004 |title=Low free testosterone is an independent risk factor for Alzheimer's disease |journal=Experimental Gerontology |volume=39 |issue=11–12 |pages=1633–39 |doi=10.1016/j.exger.2004.06.019 |pmid=15582279 |s2cid=24803152}}</ref><ref name="pmid14745052">{{cite journal |vauthors=Moffat SD, Zonderman AB, Metter EJ, Kawas C, Blackman MR, Harman SM, Resnick SM |date=Jan 2004 |title=Free testosterone and risk for Alzheimer disease in older men |url=https://escholarship.org/uc/item/9kh190b5 |journal=Neurology |volume=62 |issue=2 |pages=188–93 |doi=10.1212/WNL.62.2.188 |pmid=14745052 |s2cid=10302839 |access-date=April 1, 2022 |archive-date=November 19, 2022 |archive-url=https://web.archive.org/web/20221119073953/https://escholarship.org/uc/item/9kh190b5 |url-status=live }}</ref> a key argument in [[life extension]] 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 |vauthors=Moffat SD, Hampson E |date=Apr 1996 |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 |doi=10.1016/0306-4530(95)00051-8 |pmid=8817730 |s2cid=7135870}}</ref> where both hypo- and hypersecretion (deficient- and excessive-secretion) of circulating androgens have negative effects on cognition.

==== Immune system and inflammation ====
Testosterone deficiency is associated with an increased risk of [[metabolic syndrome]], [[cardiovascular disease]] and [[Mortality rate|mortality]], which are also sequelae of chronic [[inflammation]].<ref name="pmid30582096">{{cite journal |vauthors=Bianchi VE |date=January 2019 |title=The Anti-Inflammatory Effects of Testosterone |journal=Journal of the Endocrine Society |volume=3 |issue=1 |pages=91–107 |doi=10.1210/js.2018-00186 |pmc=6299269 |pmid=30582096}}</ref> Testosterone plasma concentration inversely correlates to multiple [[biomarker]]s of inflammation including [[C-reactive protein|CRP]], [[interleukin 1 beta]], [[interleukin 6]], [[TNF alpha]] and [[endotoxin]] concentration, as well as [[leukocyte]] count.<ref name="pmid30582096" /> As demonstrated by a [[meta-analysis]], substitution therapy with testosterone results in a significant reduction of inflammatory markers.<ref name="pmid30582096" /> These effects are mediated by different mechanisms with synergistic action.<ref name="pmid30582096" /> In androgen-deficient men with concomitant [[autoimmune thyroiditis]], substitution therapy with testosterone leads to a decrease in [[thyroid autoantibody]] titres and an increase in [[thyroid's secretory capacity]] (SPINA-GT).<ref>{{cite journal |vauthors=Krysiak R, Kowalcze K, Okopień B |date=October 2019 |title=The effect of testosterone on thyroid autoimmunity in euthyroid men with Hashimoto's thyroiditis and low testosterone levels |journal=Journal of Clinical Pharmacy and Therapeutics |volume=44 |issue=5 |pages=742–749 |doi=10.1111/jcpt.12987 |pmid=31183891 |s2cid=184487697 |doi-access=free}}</ref>

==== Medical use ====
{{Main|Testosterone (medication)}}

Testosterone is used as a medication for the treatment of [[male hypogonadism]], [[gender dysphoria]], and certain types of [[breast cancer]].<ref name="AHFS2016" /><ref>{{cite web |title=List of Gender Dysphoria Medications (6 Compared) |url=https://www.drugs.com/condition/gender-dysphoria.html |access-date=6 May 2020 |website=Drugs.com |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> This is known as [[hormone replacement therapy]] (HRT) or testosterone replacement therapy (TRT), which maintains serum testosterone levels in the normal range. [[andropause|Decline of testosterone production with age]] has led to interest in [[androgen replacement therapy]].<ref name="pmid16985841">{{cite journal |vauthors=Myers JB, Meacham RB |year=2003 |title=Androgen replacement therapy in the aging male |journal=Reviews in Urology |volume=5 |issue=4 |pages=216–226 |pmc=1508369 |pmid=16985841}}</ref> It is unclear if the use of testosterone for low levels due to aging is beneficial or harmful.<ref name="FDA2015">{{cite web |date=3 March 2015 |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/drugs/drug-safety-and-availability/fda-drug-safety-communication-fda-cautions-about-using-testosterone-products-low-testosterone-due |access-date=5 March 2015 |work=[[FDA]] |archive-date=April 22, 2021 |archive-url=https://web.archive.org/web/20210422205532/https://www.fda.gov/drugs/drug-safety-and-availability/fda-drug-safety-communication-fda-cautions-about-using-testosterone-products-low-testosterone-due |url-status=live }}</ref>

Testosterone is included in the [[WHO Model List of Essential Medicines|World Health Organization's list of essential medicines]], which are the most important medications needed in a basic [[health system]].<ref name="WHO2015E">{{cite web |date=April 2015 |title=19th WHO Model List of Essential Medicines (April 2015) |url=https://www.who.int/medicines/publications/essentialmedicines/EML2015_8-May-15.pdf |access-date=May 10, 2015 |publisher=WHO |archive-date=May 13, 2015 |archive-url=https://web.archive.org/web/20150513043105/http://www.who.int/medicines/publications/essentialmedicines/EML2015_8-May-15.pdf |url-status=live }}</ref> It is available as a [[generic medication]].<ref name="AHFS2016" /> It can be administered as a cream or [[transdermal patch]] that is applied to the skin, by [[intramuscular injection|injection into a muscle]], as a tablet that is [[Buccal administration|placed in the cheek]], or by ingestion.<ref name="AHFS2016" />

Common [[side effect]]s from testosterone medication include [[acne]], [[swelling (medical)|swelling]], and [[gynecomastia|breast enlargement in males]].<ref name="AHFS2016" /> Serious side effects may include [[liver toxicity]], [[Cardiovascular disease|heart disease]] (though a randomized trial found no evidence of major adverse cardiac events compared to placebo in men with low testosterone<ref>{{cite journal | vauthors = Lincoff AM, Bhasin S, Flevaris P, Mitchell LM, Basaria S, Boden WE, Cunningham GR, Granger CB, Khera M, Thompson IM, Wang Q, Wolski K, Davey D, Kalahasti V, Khan N, Miller MG, Snabes MC, Chan A, Dubcenco E, Li X, Yi T, Huang B, Pencina KM, Travison TG, Nissen SE | title = Cardiovascular Safety of Testosterone-Replacement Therapy | journal = The New England Journal of Medicine | volume = 389 | issue = 2 | pages = 107–117 | date = July 2023 | pmid = 37326322 | doi = 10.1056/NEJMoa2215025 | s2cid = 259176370 }}</ref>), and behavioral changes.<ref name="AHFS2016" /> Women and children who are exposed may develop [[virilization]].<ref name="AHFS2016" /> It is recommended that individuals with [[prostate cancer]] not use the medication.<ref name="AHFS2016" /> It can cause harm if used during [[pregnancy]] or [[breastfeeding]].<ref name="AHFS2016" />

2020 guidelines from the [[American College of Physicians]] support the discussion of [[testosterone (medication)|testosterone]] treatment in adult men with age-related [[Low T|low levels of testosterone]] who have [[sexual dysfunction]]. 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 |date=January 2020 |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 |volume=172 |issue=2 |pages=126–133 |doi=10.7326/M19-0882 |pmid=31905405 |doi-access=}}</ref><ref name="MSCP-20200107">{{cite news |date=7 January 2020 |title=New Guideline for Testosterone Treatment in Men With 'Low T' |work=Medscape.com |url=https://www.medscape.com/viewarticle/923449 |access-date=7 January 2020 |vauthors=Parry NM |archive-date=January 8, 2020 |archive-url=https://web.archive.org/web/20200108011908/https://www.medscape.com/viewarticle/923449 |url-status=live }}</ref>

No immediate short term effects on mood or behavior were found from the administration of [[wikt:supraphysiological|supraphysiologic]] doses of testosterone for 10 weeks on 43 healthy men.<ref name="pmid8637535">{{cite journal |vauthors=Bhasin S, Storer TW, Berman N, Callegari C, Clevenger B, Phillips J, Bunnell TJ, Tricker R, Shirazi A, Casaburi R |date=July 1996 |title=The effects of supraphysiologic doses of testosterone on muscle size and strength in normal men |journal=The New England Journal of Medicine |volume=335 |issue=1 |pages=1–7 |doi=10.1056/NEJM199607043350101 |pmid=8637535 |s2cid=73721690 |doi-access=free}}</ref>