A reference work, not a recommendation to use: this profile describes mechanism and evidence and does not replace medical advice. The claims come from marketing and forums and are tested here, not endorsed.

Claims checked

  • Builds muscle mass and strength in healthy men

    Proven benefit

    Muscle & performance · healthy · Human, randomised small studiesEvery study behind this level and result had fewer than 100 participants. Small studies report larger effects on average than large ones, so the result is less certain.

    Randomized study in 43 healthy men over ten weeks with four groups: at clearly supraphysiologic levels, muscle cross-sectional areas and strength increased compared with sham treatment even without training, most strongly with strength training (lean mass on average +6.1 kg) [3]. The effect is thus established – the ten-week study says nothing about tolerability with long-term use, for which see `risiken` [7][8].[7][8]

  • Restores libido and sexual function in older men with low levels

    Only proven in patients

    Libido & sexual function · Patients: men aged 65 and older with low testosterone levels and symptoms · Human, randomised

    In the Testosterone Trials (790 participants, one year), sexual activity, desire, and erectile function improved significantly [4]. The guideline limits treatment to men with symptoms and clearly low, repeatedly measured values [6]; for men with normal values, this benefit has not been tested.

  • Makes you vital and capable again in old age

    No benefit

    Energy & metabolism · Patients: men aged 65 and older with low testosterone levels and symptoms · Human, randomised

    In the Testosterone Trials there was no benefit for vitality (FACIT-Fatigue scale); walking distance in the six-minute walk test did not differ in the physical function trial, only across all three trials (20.5% versus 12.6%). Mood and depressive symptoms improved slightly [4].

  • Testosterone treatment is safe for the heart

    Mixed results

    Heart & blood vessels · Patients: hypogonadism with existing or high cardiovascular risk · Human, randomised manufacturer-fundedAccording to their funding or competing-interest statements, all studies behind this result were paid for, wholly or in part, by the maker of the product or compound, or list employees of the maker among their authors. Manufacturer-funded studies on average come out more favourably for the product.

    TRAVERSE (5246 men, mean follow-up 33 months) showed noninferiority for the primary endpoint of cardiovascular death, nonfatal heart attack, and nonfatal stroke (7.0% versus 7.3%; hazard ratio 0.96; 95% CI 0.78–1.17). At the same time, atrial fibrillation, acute kidney injury, and pulmonary embolism occurred more often; the study was manufacturer-funded (AbbVie and others) [5]. The prescribing information also names post-authorization studies with an increased risk of heart attack and stroke [8].

small studies: Every study behind this level and result had fewer than 100 participants. Small studies report larger effects on average than large ones, so the result is less certain.

manufacturer-funded: According to their funding or competing-interest statements, all studies behind this result were paid for, wholly or in part, by the maker of the product or compound, or list employees of the maker among their authors. Manufacturer-funded studies on average come out more favourably for the product.

Mechanism of action

Evidence map: Testosterone

Each line stands for a published finding; line style and color show where it comes from. The filter hides weaker evidence levels. Sources: see references.

Testosterone acts via the androgen receptor, but is converted in the body into two other active hormones, and only this split explains its effects. In a study of 400 healthy men, the body's own hormone production was shut down with a GnRH analog and testosterone was then given in graded amounts, in a second arm together with an aromatase inhibitor. Result: the androgen deficiency explained the loss of lean mass, muscle size, and strength, the estrogen deficiency mainly the increase in body fat, and both contributed to the decline in desire and sexual function [1]. Part of what is called “testosterone effect” is therefore estradiol effect. The second conversion pathway leads via 5α-reductase to the more potent dihydrotestosterone; this enzyme is present in high concentration only in the prostate, the scalp, and the genital skin, which is why its inhibition acts specifically there [2].

That testosterone builds muscle in healthy men has been shown in randomized trials since 1996. In a study of 43 normal-weight men with four groups – sham treatment or testosterone, each with and without strength training, over ten weeks at clearly supraphysiologic levels – muscle cross-sectional areas in the arm and thigh as well as strength in the bench press and squat increased compared with sham treatment even without training. With training, the gain in lean mass was largest (mean increase 6.1 kg), as was the strength gain. Mood and behavior did not change in any group [3]. This study is the scientific basis of the claim in the scene – and its limits matter: ten weeks, young healthy men, supervision within a study setting, no statement about years of use.

In the approved use, the balance looks different. In the Testosterone Trials, 790 men aged 65 and older with low levels and matching symptoms received testosterone or sham gel for one year. Sexual activity, desire, and erectile function improved clearly; walking distance in the six-minute walk test did not differ in the physical function trial, but did across all three trials (20.5% versus 12.6% with an improvement of at least 50 meters); for vitality there was no benefit, for mood and depressive symptoms a small one [4]. The largest safety study, TRAVERSE, tested in 5246 men aged 45 to 80 with hypogonadism and existing or high risk of cardiovascular disease whether testosterone gel raises the risk of major cardiac events: the primary endpoint occurred in 7.0% versus 7.3% (hazard ratio 0.96; 95% confidence interval 0.78–1.17), so noninferiority was shown. However, atrial fibrillation, acute kidney injury, and pulmonary embolism were more frequent under testosterone; the study was funded by AbbVie and other funders [5]. The Endocrine Society guideline recommends treatment only in men with symptoms and clearly low values measured repeatedly in the morning, and lists a number of contraindications, including breast and prostate cancer, an abnormal prostate palpation finding, elevated hematocrit, untreated severe sleep apnea, uncontrolled heart failure, and heart attack or stroke within the last six months; anyone who wants children in the near future should not be treated [6].

Abuse follows different rules than therapy, and for good reason there are no randomized studies on it. A statement by the Endocrine Society notes that most users of performance-enhancing drugs are not competitive athletes but strength trainees, that far supraphysiologic amounts and often combinations with other drugs are used, and that use is associated with increased mortality and with diseases of the heart and circulation, psyche, metabolism, hormone system, nervous system, liver, kidneys, and musculoskeletal system, as well as with infections; randomized studies could not ethically reproduce these conditions, which is why observational data are needed. A withdrawal syndrome after stopping anabolic androgenic steroids has also been described [7]. The prescribing information names the same connection from the authorization perspective: testosterone is a controlled substance in the United States, abuse and misuse occur in adults and adolescents of both sexes, and consequences of steroid abuse reported include cardiac arrest, heart attack, thickened heart muscle, heart failure, stroke, liver damage, and severe psychiatric disorders up to mania, delusions, and hostility, in men additionally testicular shrinkage, fertility disorders, and infertility, in adolescents premature closure of the growth plates [8]. Legally, testosterone is prescription-only in Germany [9] and is named as an anabolic androgenic steroid in the Annex to the German Anti-Doping Act [10]; in the EU there is no central authorization for men, the two former centrally authorized products for women have been withdrawn [11], and the products listed in Germany are depot injections and preparations for the skin [12], in the United States additionally capsules [13].

Targets

TargetTypeActionKey dataEvidence
Androgen receptorReceptorAgonistandrogen deficiency explained the loss of lean mass, muscle size, and strength in a randomized study Human, randomised[1]
Aromatase (CYP19A1)EnzymeSubstrate (conversion to estradiol)with an aromatase inhibitor, mainly the increase in body fat from the estrogen effect remained Human, randomised[1]
5α-reductaseEnzymeSubstrate (conversion to dihydrotestosterone)enzyme in high concentration only in the prostate, scalp, and genital skin (review) Human, non-randomised[2]
Hypothalamic-pituitary-gonadal axisHormone axisInhibitorExogenous androgens can lead to azoospermia according to the prescribing information Human, randomised[8]

Effect profile

Which signaling systems the compound affects according to current data. ↑ enhanced, ↓ dampened, ≈ modulated, ○ no effect; dots = evidence level.

  • Dopamineno data
  • Noradrenalineno data
  • Serotoninno data
  • Acetylcholineno data
  • Glutamate · AMPAno data
  • Glutamate · NMDAno data
  • GABAno data
  • Histamineno data
  • Orexinno data
  • Adenosineno data
  • Opioidsno data
  • Melatoninno data
  • Neurotrophinsno data
  • Blood flowno data
  • Nitric oxideno data
  • Energy metabolismmodulated · Lean mass, muscle size, and strength depend on the androgen, the body fat percentage mainly on estradiol[1][3]
  • Insulin · glucoseno data
  • Inflammation · oxidativeno data
  • Stress axisno data
  • Testosterone axismodulated · Administered testosterone replaces the body's own production and suppresses it via feedback; testicular shrinkage and azoospermia can result[1][7][8]
  • Endocannabinoidsno data
  • Autophagy · senescenceno data
  • Immune systemno data
  • Lipid metabolismno data
  • Coagulation · fibrinolysismodulated · In TRAVERSE, pulmonary embolisms occurred more often; the prescribing information names venous thromboembolism including leg vein thrombosis and pulmonary embolism[5][8]
  • Methylationno data

Routes of administration and bioavailability

How much of a compound reaches the blood or target tissue depends on the route into the body and on the dosage form. All routes of administration explained

  • Transdermal (through the skin) · Gel or solution for application to the skin

    not determined

    Both large studies used testosterone as a gel on the skin [4][5]. For Germany, Testogel, Testotop, Testavan, and Tostran are listed in the Article 57 database [12]. The US prescribing information carries a boxed warning on this: through skin contact, testosterone can be transferred to children and cause virilization there [8].[4][5]

    Human, randomised

  • Intramuscular · Depot injection (testosterone undecanoate, testosterone enanthate)

    not determined

    The randomized muscle-building study in healthy men used injections into the muscle [3]; in Germany, Nebido is listed as a depot injection [12]. On amounts, intervals, and comparisons between esters, this profile deliberately gives no information.

    Human, randomised

  • Oral (swallowed) · Capsules with testosterone undecanoate

    not determined

    In the United States, JATENZO, TLANDO, and KYZATREX are approved as capsules (openFDA query on October 25, 2026) [13]. No oral product was checked for Germany; the Article 57 database lists injections and preparations for the skin for Germany [12].

    No data

Human studies

  • Muscle building in healthy men

    RCT, double-blind, placebo-controlled, four groups (with and without strength training) · healthy · n = 43 · 10 weeks

    Measured: lean mass, muscle cross-sectional area (MRI), strength (bench press, squat)

    Result: Without training, muscle cross-sectional areas and strength increased under testosterone compared with placebo; with training, the gain in lean mass was largest (on average +6.1 kg). Mood and behavior remained unchanged in all groups.[3]

    Human, randomised

  • Testosterone Trials in older men

    RCT, double-blind, placebo-controlled, three linked trials · Patients: men aged 65 and older with low testosterone levels and symptoms · n = 790 · 1 year

    Measured: sexual function, physical function (six-minute walk test), vitality

    Result: Sexual activity, desire, and erectile function significantly better; walking distance without difference in the physical function trial, significant across all trials (20.5% versus 12.6%); no benefit for vitality, small benefit for mood and depressive symptoms. The number of participants was too small for statements on risks.[4]

    Human, randomised

  • TRAVERSE: cardiovascular safety

    RCT, double-blind, placebo-controlled, noninferiority study, multicenter · Patients: hypogonadism with existing or high cardiovascular risk (aged 45–80) · n = 5246 · mean treatment 21.7 months, mean follow-up 33.0 months

    Measured: cardiovascular death, nonfatal heart attack, or nonfatal stroke

    Result: 182 (7.0%) versus 190 (7.3%) events; hazard ratio 0.96 (95% CI 0.78–1.17), noninferiority reached. More frequent under testosterone: atrial fibrillation, acute kidney injury, pulmonary embolism. Funding by AbbVie and others.[5]

    Human, randomised

  • Separation of androgen and estrogen effects

    RCT with suppression of the body's own hormone production, graded administration, second arm with an aromatase inhibitor · healthy (men aged 20 to 50) · n = 400 · 16 weeks

    Measured: body fat percentage and lean mass (primary), thigh muscle area, strength, sexual function

    Result: Androgen deficiency explained the loss of lean mass, muscle size, and strength; estrogen deficiency mainly the increase in body fat; both contributed to the decline in sexual function.[1]

    Human, randomised

Risks and warnings

  • Suppression of the body's own production, testicular shrinkage, infertility

    Exogenous androgens can lead to azoospermia according to the prescribing information; under abuse, testicular shrinkage, reduced fertility, and infertility are reported [8]. The guideline advises against treatment when children are planned in the near future [6]. A withdrawal syndrome has been described after stopping anabolic androgenic steroids [7].

    Human, randomised

  • Heart, circulation, and vessels

    In TRAVERSE, major cardiac events did not occur more often, but atrial fibrillation, acute kidney injury, and pulmonary embolism did [5]. The prescribing information names venous thromboembolism including leg vein thrombosis and pulmonary embolism, post-authorization studies with an increased risk of heart attack and stroke, and edema up to heart failure in pre-existing heart, kidney, or liver disease [8]. Under abuse of far supraphysiologic amounts, cardiac arrest, heart attack, thickened heart muscle, heart failure, and stroke are reported [7][8].

    Human, randomised

  • Prostate and mammary gland

    According to the prescribing information, it is contraindicated in breast cancer and in known or suspected prostate cancer, requires monitoring of benign prostatic enlargement, and points to a possibly increased risk of prostate cancer under androgens; PSA, hematocrit, liver values, and blood lipids should be checked regularly [8]. The guideline names an abnormal palpation finding and elevated PSA values as reasons not to treat without urological clarification [6].

    Human, randomised

  • Blood count and sleep apnea

    The prescribing information requires monitoring of hemoglobin and hematocrit and names the occurrence of sleep apnea in the presence of corresponding risk factors [8]; the guideline lists elevated hematocrit and untreated severe sleep apnea as contraindications [6].

    Human, randomised

  • Abuse, psychiatric consequences, and dependence

    Testosterone is a Schedule III controlled substance in the United States; abuse and misuse are described in adults and adolescents, including continuing against medical advice. Severe psychiatric disorders are named as consequences of steroid abuse, including depression, mania, paranoia, psychosis, delusions, hallucinations, hostility, and aggression; in adolescents additionally premature closure of the growth plates with growth arrest [8]. The Endocrine Society notes that use of performance-enhancing drugs is associated with increased mortality and with diseases of numerous organ systems, and describes a withdrawal syndrome [7]. Anyone who uses testosterone without medical supervision or wants to stop will find help at a primary care practice or an addiction counseling service.

    Human, non-randomised

  • Transfer through skin contact

    Boxed warning of the prescribing information: with preparations for the skin, virilization in children has been reported after unintended contact with the application site; use is contraindicated in pregnant women because testosterone can virilize a female fetus [8].

    Human, randomised

  • Doping and legal consequences

    Testosterone is named in the Annex to the German Anti-Doping Act among the anabolic androgenic steroids; Section 2 paragraph 3 AntiDopG prohibits acquisition, possession, and bringing into the country in a not insignificant quantity for the purpose of doping in sport [10]. In Germany, testosterone is also prescription-only [9]. This is a reproduction of the norms, not legal advice.

    No data

Interactions

  • Aromatase inhibitors: If the conversion to estradiol is blocked, the estrogen-dependent effects drop out: in the randomized study with an aromatase inhibitor, mainly the body fat percentage rose, and sexual function suffered more [1]. This explains why the combination with aromatase inhibitors that is common in the scene is not a consequence-free correction; this profile gives no procedures or amounts.
  • 5α-reductase inhibitors (finasteride, dutasteride): They suppress the conversion to dihydrotestosterone, which takes place mainly in the prostate, scalp, and genital skin [2]; the androgenic effect of testosterone itself is not affected by this.
  • Other performance-enhancing drugs: In abuse, several drugs are regularly used together, often in addition to classic recreational drugs; the consequences can then not be attributed to any single substance [7].

Fact check: common claims

  • supported

    “Testosterone builds muscle even without training”

    In the randomized study, muscle cross-sectional areas and strength increased compared with placebo even in the group without training; with training, the effect was larger [3].

  • partly supported

    “Testosterone makes you aggressive”

    In the ten-week randomized study in healthy men, mood and behavior did not change in any group [3]. Under abuse of far supraphysiologic amounts, however, irritability, hostility, aggression, mania, and delusions are reported [7][8]. The claim thus does not apply to the tested use, but it does apply to what is reported from abuse.

  • refuted

    “Testosterone treatment makes older men vital again”

    In the Testosterone Trials there was no benefit for vitality; only sexual function and, to a smaller degree, mood improved [4].

  • partly supported

    “Testosterone treatment is heart-safe”

    For major cardiac events, TRAVERSE showed noninferiority, not harmlessness overall: atrial fibrillation, acute kidney injury, and pulmonary embolism occurred more often [5]; the prescribing information names venous thromboembolism and post-authorization studies with an increased risk of heart attack and stroke [8].

  • not supported

    “After stopping, everything is back to how it was”

    Testicular shrinkage, reduced fertility, and infertility as well as a withdrawal syndrome after stopping anabolic androgenic steroids are described [7][8]. How often and how completely the axis recovers has not been tested in randomized studies.

Pharmacokinetics

Absorption
In the large studies via the skin as a gel [4][5]; also as a depot injection [3][12] and, in the United States, as a capsule [13].
Half-life
Not verified; it depends on the preparation, and this profile does not compare esters.
Metabolism
Conversion to estradiol via aromatase and to dihydrotestosterone via 5α-reductase; both pathways have effects of their own [1][2].
Entry into the brain
Not verified.

Legal status

Germany
Prescription-only medicinal product: Annex 1 of the German Ordinance on Prescription-Only Medicines (AMVV) lists “testosterone and its esters” without exception (statutory text read in full on October 25, 2026) [9]. The content of the marketing authorization in Germany is not documented from an authorization source: the German summaries of product characteristics were not retrieved and national authorizations were not checked against AMIce/PharmNet. The US prescribing information of a testosterone gel names replacement therapy in men with testosterone deficiency as the indication [8]; the Endocrine Society guideline describes hypogonadism as the reason for treatment [6] – neither is a statement of German authorization. The EMA Article 57 database documents only that products containing the active substance testosterone are listed for Germany (data as of October 9, 2026), not their authorization content [12]. Doping: the Annex to the German Anti-Doping Act (to Section 2 paragraph 3) names “testosterone” under I.1 “anabolic androgenic steroids”; the closing sentence includes salts, esters, ethers, isomers, mixtures of isomers, complexes, and derivatives [10]. Paraphrase of the provision: under Section 2 paragraph 3 AntiDopG, it is prohibited to acquire, possess, or bring into the country doping agents containing a substance of this Annex in a not insignificant quantity for the purpose of doping in sport in humans.
EU
No central EU marketing authorization for use in men; these products are nationally authorized. Centrally authorized were only two patches for women with loss of sexual desire after surgical removal of both ovaries and the uterus: Intrinsa (EMEA/H/C/000634) and Livensa (EMEA/H/C/000630), both authorized since July 28, 2006 and since withdrawn (Commission decisions of May 25, 2012 and July 18, 2011, respectively) [11].
USA
Approved. Drugs@FDA lists, among others, the gels ANDROGEL, TESTIM, VOGELXO, and NATESTO, the injectable products AVEED and XYOSTED, and the capsules JATENZO, TLANDO, and KYZATREX with testosterone undecanoate (openFDA query on October 25, 2026) [13]. The US prescribing information lists testosterone as a Schedule III controlled substance [8].
Other countries
Sport: testosterone is named in the Annex to the German Anti-Doping Act [10]. The 2026 WADA Prohibited List and its German publication in Part II of the Federal Law Gazette were not retrieved for this profile.

Related compounds

DHEAsame class (German only)Clomifensame class (German only)Andarinsame class (German only)YK-11same class (German only)S-23same class (German only)

Open questions

  • How often and how completely does the body's own hormone axis recover after longer use at supraphysiologic levels?
  • Where does the higher rate of atrial fibrillation, acute kidney injury, and pulmonary embolism in TRAVERSE come from, and does it apply to all preparations?
  • At what level does clinical benefit begin in the presence of symptoms, and how well can this be measured at all?
  • Which of the harms reported in abuse are attributable to testosterone and which to the accompanying drugs?

References

  1. Finkelstein JS, Lee H, Burnett-Bowie SA, Pallais JC, Yu EW, Borges LF, Jones BF, et al. Gonadal steroids and body composition, strength, and sexual function in men. N Engl J Med. 2013;369(11):1011–22. doi:10.1056/NEJMoa1206168 · PubMed
  2. Steiner JF. Clinical pharmacokinetics and pharmacodynamics of finasteride. Clin Pharmacokinet. 1996;30(1):16–27. doi:10.2165/00003088-199630010-00002 · PubMed
  3. Bhasin S, Storer TW, Berman N, Callegari C, Clevenger B, Phillips J, Bunnell TJ, et al. The effects of supraphysiologic doses of testosterone on muscle size and strength in normal men. N Engl J Med. 1996;335(1):1–7. doi:10.1056/NEJM199607043350101 · PubMed
  4. Snyder PJ, Bhasin S, Cunningham GR, Matsumoto AM, Stephens-Shields AJ, Cauley JA, Gill TM, et al. Effects of testosterone treatment in older men. N Engl J Med. 2016;374(7):611–24. doi:10.1056/NEJMoa1506119 · PubMed
  5. Lincoff AM, Bhasin S, Flevaris P, Mitchell LM, Basaria S, Boden WE, Cunningham GR, et al. Cardiovascular safety of testosterone-replacement therapy. N Engl J Med. 2023;389(2):107–17. doi:10.1056/NEJMoa2215025 · PubMed
  6. Bhasin S, Brito JP, Cunningham GR, Hayes FJ, Hodis HN, Matsumoto AM, Snyder PJ, et al. Testosterone therapy in men with hypogonadism: an Endocrine Society clinical practice guideline. J Clin Endocrinol Metab. 2018;103(5):1715–44. doi:10.1210/jc.2018-00229 · PubMed
  7. Pope HG Jr, Wood RI, Rogol A, Nyberg F, Bowers L, Bhasin S. Adverse health consequences of performance-enhancing drugs: an Endocrine Society scientific statement. Endocr Rev. 2014;35(3):341–75. doi:10.1210/er.2013-1058 · PubMed
  8. U.S. Food and Drug Administration. Fachinformation (Prescribing Information, Structured Product Labeling) für Testosteron-Gel, NDA 022309, Prasco Laboratories; SPL-Set-ID 0d84e5a6-11e9-4940-8991-21c611c4c32f, Fassung 4 vom 30.09.2024. Abschnitte Rahmenwarnung, 1, 4, 5 und 9 [Internet]. Abgerufen über die openFDA-Schnittstelle (api.fda.gov/drug/label.json) am 25.10.2026. Ausländische Fachinformation; die deutschen Fachinformationen der hier genannten Präparate wurden nicht abgerufen (Rechercheauftrag docs/AUFTRAG-RECHTSSTATUS.md).
  9. Verordnung über die Verschreibungspflicht von Arzneimitteln (Arzneimittelverschreibungsverordnung – AMVV), Anlage 1 (zu § 1 Nr. 1 und § 5), Eintrag „Testosteron und seine Ester“. https://www.gesetze-im-internet.de/amvv/anlage_1.html (abgerufen am 25.10.2026).
  10. Gesetz gegen Doping im Sport (Anti-Doping-Gesetz – AntiDopG), § 2 Absatz 3 (https://www.gesetze-im-internet.de/antidopg/__2.html) und Anlage (zu § 2 Absatz 3), I.1 „Anabol-androgene Steroide“, Eintrag „Testosteron“, mit Schlusssatz zu Salzen, Estern, Ethern, Isomeren, Isomerengemischen, Komplexen und Derivaten. Fundstelle der Anlage: BGBl. 2023 I Nr. 67, 1–5. https://www.gesetze-im-internet.de/antidopg/anlage.html (abgerufen am 25.10.2026).
  11. European Medicines Agency. Medicines: Datenexport (JSON) der zentral bewerteten Arzneimittel, 2754 Datensätze, Zeitstempel 24.10.2026: Intrinsa (Testosteron, EMEA/H/C/000634, Zulassung 28.07.2006, Status „Withdrawn“, Kommissionsbeschluss 25.05.2012) und Livensa (EMEA/H/C/000630, Zulassung 28.07.2006, Status „Withdrawn“, Kommissionsbeschluss 18.07.2011). Amsterdam: EMA. https://www.ema.europa.eu/en/documents/report/medicines-output-medicines_json-report_en.json (abgerufen am 25.10.2026).
  12. European Medicines Agency. Article 57 product data (EMA/518502/2018, Rev. 90), Datenstand 09.10.2026: Produkte mit dem Wirkstoff Testosteron und Zulassungsland Deutschland, darunter Nebido (Injektion in den Muskel, Testosteronundecanoat, 25 Länder), Testogel (19 Länder), Testavan (19 Länder), Tostran (9 Länder) und Testotop. Amsterdam: EMA. https://www.ema.europa.eu/en/documents/other/article-57-product-data_en.xlsx (abgerufen am 25.10.2026).
  13. U.S. Food and Drug Administration. Drugs@FDA (openFDA-Abfrage nach dem Wirkstoff Testosteron, 89 Datensätze): ANDROGEL (NDA 021015, NDA 022309), TESTIM (NDA 021454), VOGELXO (NDA 204399), NATESTO (NDA 205488), AVEED (NDA 022219), XYOSTED (NDA 209863), JATENZO (NDA 206089), TLANDO (NDA 208088), KYZATREX (NDA 213953) [Internet]. Abgerufen am 25.10.2026. Verfügbar unter: https://api.fda.gov/drug/drugsfda.json?search=products.active_ingredients.name:%22TESTOSTERONE%22
How this profile was checked

Last reviewed: 2026-10-25. All sources with a DOI or PMID were resolved automatically via Crossref or doi.org and PubMed.

Translated from the German profile (version of 2026-10-25); translation checked on 2026-10-26.

Checked

  • All study statements are based on the abstracts (abstract only checked, q012); the risks come from the sections boxed warning, 1, 4, 5, and 9 of the US prescribing information, which were read in full text via openFDA [8].
  • Key figures at the abstracts: 400 healthy men, 16 weeks, androgen deficiency explains lean mass, muscle size, and strength, estrogen deficiency mainly body fat, both sexual function [1]; 5α-reductase converts testosterone to dihydrotestosterone in the prostate, high enzyme concentration only in prostate, scalp, and genital skin [2]; n = 43, four groups, 10 weeks, muscle cross-sectional area and strength higher even without training, with training lean mass +6.1 kg, mood and behavior unchanged [3]; n = 790, one year, sexual function significantly better, walking distance only across all three trials (20.5% versus 12.6%), vitality without benefit, mood slightly better, number of participants too small for statements on risks [4]; n = 5246, treatment on average 21.7 months, follow-up 33.0 months, primary endpoint 7.0% versus 7.3%, HR 0.96 (95% CI 0.78–1.17), more frequent atrial fibrillation, acute kidney injury, and pulmonary embolism, funding AbbVie and others [5]; guideline recommendations and contraindications taken verbatim from the abstract [6]; statement on performance-enhancing drugs: mostly strength trainees, far supraphysiologic amounts, combinations, increased mortality and diseases of many organ systems, withdrawal syndrome, randomized studies ethically not possible [7].
  • Legal status checked against primary sources on October 25, 2026: AMVV Annex 1 in full text, entry “Testosteron” with the addition “und seine Ester” [9]; Annex to the AntiDopG in full text, “Testosteron” under I.1, closing sentence verbatim [10]; EMA data export (2754 records) with exactly two testosterone entries, both withdrawn [11]; EMA Article 57 database downloaded and evaluated (249 rows with testosterone, 23 product names listed for Germany; products made up of active substance and company name not included) [12]; Drugs@FDA queried via openFDA, 89 records [13].
  • Trade names (q018): Nebido, Testogel, Testotop, Testavan, and Tostran included in `synonyme`, all listed in the Article 57 database with country of authorization Germany [12]. Not included: products made up of active substance and company name (e.g., “Testosteron Ratiopharm”), brand names with strength stated in the name, and products not listed for Germany (e.g., AndroGel, listed in 11 other countries).
  • E-15 implemented: presentation of abuse according to the rules “drugs and medicinal products” – no amounts, no intervals, no cycles, no comparison of esters, no information on sourcing or prescriptions. The scene claim comes first with `population` “gesund”, the approved indication as a claim with “Patienten: …” and in `status`.
  • Chemistry retrieved from PubChem (CID 6013) on October 25, 2026.
  • DOIs and PMIDs checked online against Crossref and PubMed with tools/pruefe_profile.py.
  • Cross-check October 25, 2026, q018: the trade names Nebido, Testogel, Testotop, Testavan, and Tostran were removed from `synonyme`. They were documented solely by the EMA database under Article 57 [12]; the guideline names only EPAR, summary of product characteristics, and Drugs@FDA as evidence for trade names (guideline “Handelsnamen”, q018). Own check on October 25, 2026: openFDA/Drugs@FDA returns no hit for any of the five names as a brand name (NOT_FOUND); no EPAR exists (centrally authorized were only Intrinsa and Livensa, both withdrawn). This profile is thus treated in the same way as `clomifen`, from which “Clostilbegyt” was removed for the same reason. The listing itself remains documented as a fact in `status.deutschland` and in reference 12.
  • Cross-check October 25, 2026: the statement on the German authorization content had been documented with the Endocrine Society guideline [6], i.e., with a professional society source rather than an authorization source. `status.deutschland` now states explicitly that the authorization content is not documented, and separates AMVV (prescription requirement), US prescribing information (US indication), and Article 57 listing.
  • Cross-links “same class” (q099): the shared mechanism with `andarin`, `yk-11`, and `s-23` is action via the androgen receptor with feedback inhibition of the hypothalamic-pituitary-gonadal axis; with `dhea` the position in androgen metabolism (DHEA as precursor), with `clomifen` the control of the same axis from the opposite side.
  • October 25, 2026, trade names harmonized (q018; guideline “Handelsnamen”, decision of October 25, 2026: the EMA database under Art. 57 counts as a source on a par with EPAR, summary of product characteristics, and Drugs@FDA): Nebido, Testogel, Testotop, Testavan, and Tostran added back to `synonyme`; the removal from the cross-check is thereby reversed. Source, rechecked in the list: EMA database under Art. 57 (Article 57 product data, EMA/518502/2018 Rev. 90, data as of October 9, 2026, retrieved October 25, 2026) [12]: “Nebido” (injection into the muscle, testosterone undecanoate) in 25 countries or territories, “Testogel” (transdermal) in 19, “Testavan” (transdermal) in 19, “Tostran” (transdermal) in 9, and “Testotop” (cutaneous) in one, in each case including Germany. Still not included: products made up of active substance and company name (e.g., “Testosteron Ratiopharm”), names with strength or additional information (e.g., “Testoviron-Depot-250”, “Testogel Dosiergel”), and names not listed for Germany (e.g., AndroGel, listed in eleven other countries; the list here is limited to the names listed in Germany). The listing does not document the authorization content; status.deutschland is unchanged.
  • October 25, 2026, correction of trade names (guideline “Handelsnamen”, order of precedence: names listed in Germany first, then names from other EU/EEA countries; the base name counts if it is itself listed): “Androgel” and “Testoviron” added after the German names in synonyme. The two reasons for exclusion in the note above are superseded to that extent: the guideline knows no restriction to names listed in Germany (other profiles of the same round list EU names without a listing for Germany, e.g., minoxidil and modafinil), and for “Testoviron-Depot-250” the base name counts because it is itself listed. Source, rechecked in the list: EMA database under Art. 57 (Article 57 product data, EMA/518502/2018 Rev. 90, data as of October 9, 2026, retrieved October 25, 2026) [12]: “Androgel” (transdermal, testosterone) in eleven countries (Belgium, France, Ireland, Croatia, Luxembourg, the Netherlands, Austria, Portugal, Romania, the Czech Republic, Hungary), not in Germany; “Testoviron” (injection into the muscle, testosterone enanthate) in Italy, “Testoviron Depot” in Portugal, and “Testoviron-Depot-250” in Germany. Other names listed only outside Germany (including Testarzon in seven countries, Testonur in four) were not adopted because the guideline regulates the order of precedence, not completeness; Sustanon and Omnadren are mixtures of four testosterone esters and are listed in the list with several active substances (treated like combination products, not included). The listing does not document the authorization content; status is unchanged.
  • October 26, 2026, precision flags (m004; rules in the guideline under “Zahlenregel und Präzisions-Flags”, implemented by Claude pending confirmation by Tilman): “Builds muscle mass and strength in healthy men”: “kleine_studien” – [3] 43 men (abstract). “Testosterone treatment is safe for the heart”: “herstellerfinanziert” – [5] according to the abstract “Funded by AbbVie and others” (co-funding by the manufacturer of the study gel, pending confirmation by Tilman).

Not verified

  • German summaries of product characteristics of the named products: not retrieved. All risk statements come from the US prescribing information of a gel [8] and may differ in wording and frequency statements from the German texts (follow-up in research assignment docs/AUFTRAG-RECHTSSTATUS.md).
  • National authorizations in Germany via AMIce/PharmNet: not queried; the Article 57 database documents the listing of products, not the authorization content.
  • WADA Prohibited List 2026 in the original and the publication in Part II of the Federal Law Gazette: not retrieved.
  • Half-life and bioavailability: not adopted because they depend on the preparation and this profile does not compare esters.
  • Frequency data on abuse in Germany and data on recovery of the hormone axis after long use: no checked source.
  • The statement on 5α-reductase comes from a review on finasteride [2], not from a primary study on enzyme distribution.

No dosages, no sources of supply. This information does not replace medical advice.

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