Yes. Testosterone taken as a gel, injection or pellet, and anabolic steroids, suppress sperm production, often to zero. Testosterone from outside the body tells the brain to stop releasing the two hormones (LH and FSH) that drive sperm production in the testes. In World Health Organization trials that used weekly testosterone injections as a male contraceptive, about 65% of men had no sperm at all within six months. For this reason the American Urological Association, the European Association of Urology and the Endocrine Society all say testosterone therapy shouldn't be prescribed to men trying to conceive. The effect usually reverses: in an analysis of 1,549 men from hormonal contraception trials, sperm counts recovered to 20 million per mL in a median of 3.4 months after stopping, 90% of men recovered within a year, and the modeled probability of recovery reached 100% by two years. Recovery after anabolic steroid use is slower and less certain.
Why testosterone lowers sperm production
Sperm production is controlled by a loop between the brain and the testes. The pituitary gland releases luteinizing hormone (LH), which tells the testes to make testosterone, and follicle-stimulating hormone (FSH), which supports sperm production. The testosterone made inside the testes is what sperm production actually runs on.
When testosterone comes from outside, the brain reads the higher level in the blood and turns LH and FSH down. The testes then make less of their own testosterone and far fewer sperm, even though the blood level looks healthy or high. A 2022 review by a team of UK urologists and endocrinologists describes exactly this: the use of exogenous testosterone and anabolic steroids "suppresses male fertility by augmenting this negative feedback inhibition centrally". It is the same reason testosterone has been tested as a male contraceptive.
What the guidelines say
The major guidelines agree, and they use strong language:
- American Urological Association, testosterone deficiency guideline (2018): "Exogenous testosterone therapy should not be prescribed to men who are currently trying to conceive." It also says the long-term effect on sperm production should be discussed with men interested in future fertility.
- AUA and American Society for Reproductive Medicine, male infertility guideline (2020, amended 2024): "For the male interested in current or future fertility, clinicians should not prescribe exogenous testosterone therapy."
- European Association of Urology, male hypogonadism guideline: "Do not use TTh for the treatment of male infertility and in males wishing to be fathers."
- Endocrine Society (2018): recommends against testosterone therapy in men planning fertility in the near term.
None of this means testosterone therapy is wrong for men with genuine testosterone deficiency. It means the decision needs to include fertility plans, and ideally before the first dose.
How far sperm counts fall
The clearest numbers come from the WHO's male contraceptive trials, because they measured sperm deliberately. In the 1990 trial, 271 healthy, fertile men received 200 mg of testosterone enanthate by injection every week, and about 65% had no sperm in the ejaculate (azoospermia) by six months. A 1996 follow-up trial in 399 men tested whether that was enough to prevent pregnancy: there were no pregnancies while men were azoospermic, but pregnancies did occur at a rate of 8.1 per 100 person-years in men whose counts were very low but not zero.
Two things follow. Testosterone reliably lowers sperm production, which is why guidelines treat it as incompatible with trying to conceive. And it isn't reliable contraception on its own either, because some men keep a small number of sperm.
How long recovery takes after stopping
The best recovery data come from a 2006 integrated analysis in The Lancet that pooled 30 hormonal male contraception trials and 1,549 healthy men. After treatment stopped, the median time for sperm concentration to return to 20 million per mL was 3.4 months. The probability of reaching that level was 67% within 6 months, 90% within 12 months, 96% within 16 months and 100% within 24 months.
Recovery was somewhat faster with older age, Asian origin, shorter treatment, shorter-acting testosterone preparations, higher sperm concentrations before treatment, faster suppression and lower LH before treatment, though the authors describe these effects as minor. The men were healthy volunteers aged 18 to 51 with normal testosterone and normal sperm counts at the start, treated for about 10 months on average, some with testosterone combined with a progestogen. Men who have been on testosterone for years, or who started with a low count, may not follow the same curve, which is why the guidelines ask for the conversation before treatment rather than after.
Recovery also runs through the sperm production cycle. Even once hormone levels come back, new sperm take roughly two to two and a half months to form and reach the ejaculate, so the sperm production timeline applies on top of the hormonal recovery.
Anabolic steroids
Anabolic-androgenic steroids work on the same loop at higher and often stacked doses, usually without medical supervision. A 2014 meta-analysis estimated a global lifetime prevalence of use of 6.4% in men, with wide variation between countries and groups.
Recovery is slower. In a 2020 study comparing current and past steroid users with non-users, the estimated average time for sperm output to return to non-users' levels after stopping was about 14 months, and about 11 months for LH. The authors concluded the effects are largely reversible, over roughly 6 to 18 months. A 2016 Danish study found 27% of former users still had testosterone below the reference range an average of 2.5 years after stopping, compared with none of the non-users. A 2015 paper called prolonged low testosterone after steroid withdrawal "an under-recognized problem". Most men do recover, but the timeline is measured in months to years, and not every man returns to where he started.
SARMs, finasteride and creatine
- SARMs (selective androgen receptor modulators, sold online as "research chemicals") are not approved medicines. A 2025 review describes them suppressing the same hormones (LH and FSH) and lowering testosterone. Good data on sperm are scarce, but the mechanism is the same one that shuts down sperm production with testosterone.
- Finasteride (used at 1 mg for hair loss) has mixed evidence. In one clinic study of men with infertility, 27 men who stopped finasteride saw their sperm counts rise on average 11.6-fold. A 1999 placebo-controlled trial in 181 men aged 19 to 41 found 1 mg a day for 48 weeks had no significant effect on sperm concentration, count, motility or morphology (semen data came from 79 of the men). If you take it and are trying to conceive, raise it with your doctor rather than stopping on your own.
- Creatine has no human evidence of harming sperm. The research is thin, limited to lab and animal studies and one observational study in men, and a 2022 review even suggests it may help. It is not a testosterone and doesn't act on this hormone loop.
Why this matters more now
Testosterone prescribing is rising, particularly among younger men. Prescription monitoring data from participating US states show a 27% rise in the number of people filling testosterone prescriptions between 2018 and 2022. The biggest rises in numbers were among people aged 45 to 54 (up 35%) and 35 to 44 (up 58%), most of them men. A 2026 study of a 2023 survey of US men aged 18 to 40 found use of testosterone and related medicines often happened without a reported diagnosis of low testosterone, and increasingly through direct-to-consumer online clinics. Not every one of those consultations includes a conversation about fertility.
If you're on testosterone and want children
This is a decision to make with a urologist or andrologist, not alone. Stopping testosterone abruptly can bring back the symptoms that led to treatment, and the options depend on your hormone levels and your timeline. Specialists may stop testosterone and wait for recovery, or use medicines that restart the body's own production, such as hCG (which acts like LH on the testes), clomiphene or other selective estrogen receptor modulators (which raise LH and FSH from the brain), or FSH itself. A 2025 review describes how these are used. They are specialist prescriptions, and several are used off-label in men.
What you can do now: tell the doctor that fertility matters to you, ask for a semen analysis (see how to get one in the UK), and ask about sperm freezing before starting treatment if you're considering testosterone and haven't started yet.
What to do
- If you're trying to conceive now, don't start testosterone, anabolic steroids or SARMs. Every major guideline agrees on this.
- If you're already on prescribed testosterone, don't stop it on your own. Book a conversation with the prescriber or a urologist about fertility.
- Get a semen analysis so you and your doctor know your starting point.
- If you've used steroids, expect recovery to take months, and retest rather than assume.
- Keep the rest of the basics steady while you wait: sleep, weight, alcohol and heat all have their own evidence, ranked in the main guide.
Common questions
Does TRT make you permanently infertile?
Usually not. In an analysis of 1,549 men from hormonal contraception trials, the median time to recover to 20 million sperm per mL was 3.4 months after stopping, and the modeled probability of recovery reached 100% by 24 months. Longer use, anabolic steroid doses and a low count before treatment can slow recovery, and in one Danish study about a quarter of former steroid users still had low testosterone an average of 2.5 years after stopping.
Can you get someone pregnant while on testosterone?
It is less likely but possible. In the WHO trials some men kept a small number of sperm, and pregnancies occurred at 8.1 per 100 person-years among men with very low but non-zero counts. Testosterone is not a reliable contraceptive on its own.
Do testosterone booster supplements affect sperm?
Over-the-counter "testosterone boosters" are usually herbal or mineral blends, not testosterone, and don't act on this hormone loop the way prescribed testosterone does. Evidence that they improve sperm is weak; the supplements guide covers the ingredients with real trials.
How long after stopping steroids can I try for a baby?
There is no fixed answer. One study estimated an average of about 14 months for sperm output to return to normal levels after steroids. A semen analysis is the only way to know where you are, and a urologist can advise on whether treatment to restart production makes sense.
Related guides
Sources
- Desai A, et al. Understanding and managing the suppression of spermatogenesis caused by testosterone replacement therapy (TRT) and anabolic-androgenic steroids (AAS). Therapeutic Advances in Urology, 2022.
- Mulhall JP, et al. Evaluation and management of testosterone deficiency: AUA guideline. Journal of Urology, 2018.
- American Urological Association and American Society for Reproductive Medicine. Diagnosis and treatment of infertility in men: AUA/ASRM guideline. 2020, amended 2024.
- European Association of Urology. Guidelines on Sexual and Reproductive Health: male hypogonadism.
- Bhasin S, et al. Testosterone therapy in men with hypogonadism: an Endocrine Society clinical practice guideline. Journal of Clinical Endocrinology and Metabolism, 2018.
- World Health Organization Task Force on Methods for the Regulation of Male Fertility. Contraceptive efficacy of testosterone-induced azoospermia in normal men. The Lancet, 1990.
- World Health Organization Task Force on Methods for the Regulation of Male Fertility. Contraceptive efficacy of testosterone-induced azoospermia and oligozoospermia in normal men. Fertility and Sterility, 1996.
- Liu PY, et al. Rate, extent, and modifiers of spermatogenic recovery after hormonal male contraception: an integrated analysis. The Lancet, 2006.
- Sagoe D, et al. The global epidemiology of anabolic-androgenic steroid use: a meta-analysis and meta-regression analysis. Annals of Epidemiology, 2014.
- Shankara-Narayana N, et al. Rate and extent of recovery from reproductive and cardiac dysfunction due to androgen abuse in men. Journal of Clinical Endocrinology and Metabolism, 2020.
- Rasmussen JJ, et al. Former abusers of anabolic androgenic steroids exhibit decreased testosterone levels and hypogonadal symptoms years after cessation: a case-control study. PLOS ONE, 2016.
- Kanayama G, et al. Prolonged hypogonadism in males following withdrawal from anabolic-androgenic steroids: an under-recognized problem. Addiction, 2015.
- Bond P, et al. Selective androgen receptor modulators: a critical appraisal. Frontiers in Endocrinology, 2025.
- Samplaski MK, et al. Finasteride use in the male infertility population: effects on semen and hormone parameters. Fertility and Sterility, 2013.
- Overstreet JW, et al. Chronic treatment with finasteride daily does not affect spermatogenesis or semen production in young men. Journal of Urology, 1999.
- Ostojic SM, et al. Creatine as a promising component of paternal preconception diet. Nutrients, 2022.
- Selinger S, Thallapureddy A. Cross-sectional analysis of national testosterone prescribing through prescription drug monitoring programs, 2018 to 2022. PLOS ONE, 2024.
- Aguiar JA, et al. Testosterone use trends among young men in the era of direct-to-consumer healthcare. Journal of Sexual Medicine, 2026.
- Hochu G, et al. Preserving spermatogenesis in testosterone deficiency: innovations in replacement and stimulatory therapies. Translational Andrology and Urology, 2025.
Correction, 8 October 2026. A common question said a small number of steroid users have lasting low testosterone. The study the page cites found about a quarter still low an average of 2.5 years after stopping.
