If you're looking up how to increase testosterone and you'd like children one day, here's the bit worth knowing first: taking testosterone usually switches your own sperm production down, often to zero. The testosterone your body makes is essential for sperm. Testosterone from outside (TRT, injections, gels or anabolic steroids) works differently.
My own numbers show the difference. My semen analysis came back low in January 2024 (the whole story is in my real results article), and in February 2024 my blood testosterone came back at 17.0 nmol/L, inside the NHS range of 10.0 to 28.7 and marked "Satisfactory". My LH and FSH from the same blood test were in range too. So my testosterone was normal while my sperm wasn't, and from everything below, taking more testosterone would have pushed my sperm down further, not up.
Does Taking Testosterone Make You Infertile? (Usually, While You're On It)
Taking testosterone usually suppresses fertility while you're on it, sometimes completely, although it normally reverses after stopping. In the WHO's 1990 trial of healthy, fertile men given weekly testosterone injections, 157 of 271 ended up with no sperm at all, a cumulative 65% by six months, after about 120 days on average.
That wasn't an accident: the researchers were testing testosterone as a contraceptive.
The EAU Guidelines (2026) are pretty blunt: an active desire to have children is an absolute contraindication, and the recommendation reads: "Do not use TTh for the treatment of male infertility and in males wishing to be fathers." (TTh is testosterone therapy.)
Why Does Testosterone Stop Sperm Production? (And Why Your Blood Test Can Look Great)
Testosterone from outside makes the brain stop sending LH and FSH, the two hormones that tell the testes to make sperm. In a 2005 study of healthy men given weekly testosterone injections, LH fell to 5% and FSH to 3% of their starting levels within three weeks in the group given testosterone alone.
Testosterone from outside → the brain reads it as "plenty" → LH and FSH fall → the testes stop making their own testosterone and sperm
The catch is that sperm are made inside the testes, where testosterone is far higher: in that same study, blood testosterone was only about 1.2% of the level inside the testes.
👉 So a man on TRT can have great blood results and still be making almost no sperm.
Dr Channa Jayasena, a reproductive endocrinologist at Imperial College London, explains why testosterone levels don't tell you about sperm health in this interview (from about 40 minutes).
How Long Does Sperm Take to Come Back After Stopping Testosterone? (The Honest Table)
For most men sperm comes back within months of stopping, but most hard numbers come from healthy volunteers in contraceptive trials, not long-term TRT users. Pooling 30 studies and 1,549 healthy men, Liu et al. (The Lancet, 2006) found sperm returned to 20 million/mL in 67% within six months, 90% within 12 and 100% within 24, with a median of 3.4 months.
| Scenario | What happens to sperm | Figure | Population | Source |
|---|---|---|---|---|
| 16 weeks on testosterone gel | Marked reduction in sperm production | % not given in the study abstract | Overweight men with secondary hypogonadism | Kim 2016 |
| Pregnancy while suppressed | Low; lowest with no sperm | 8.1 per 100 person-years at 0.1 to 3 million/mL; 0 with no sperm | 399 healthy men | WHO 1996 |
| 6 months after stopping | Back to 20 million/mL | 67% | 1,549 healthy men | Liu 2006 |
| 12 months after stopping | Back to 20 million/mL | 90% | Same | Liu 2006 |
| 12 months, UK guideline figure | Fertility returns | 60 to 70% | Younger men on testosterone therapy | BSSM 2023 |
| 12 months of hCG plus a SERM | Total motile count above 5 million | 70% (46 of 66) | Men already infertile after testosterone | Kohn 2017 |
| Years of prescribed TRT, then stopping | Recovery timing highly variable | Limited (observational studies only) | Hypogonadal men | Desai 2022 |
| After non-prescribed anabolic steroids | Sperm output slower to recover than LH | Mean 14.1 months | 31 past users, Australia | Shankara-Narayana 2020 |
Sources: Kim 2016, WHO Task Force 1996, Liu 2006, BSSM 2023, Kohn 2017, Desai 2022, Shankara-Narayana 2020.
If you see "70% recover within 12 months" quoted, check what it measured: in Kohn et al. (2017), 46 of 66 already-infertile men reached a total motile count above 5 million on hCG plus a SERM. That's treatment, not waiting it out.
What Do UK Guidelines Say About Testosterone and Fertility? (NICE, BSSM and EAU)
UK and European guidance all point the same way: testosterone shouldn't be used to treat male infertility, and doctors should ask about it. The NICE fertility guideline NG257 (2026) tells clinicians to ask people worried about their fertility about testosterone-replacement therapy and anabolic steroids (recommendation 1.13.1).
On treatment, NICE's section on male fertility problems is short: "Do not offer androgens to treat semen abnormalities." Androgens are testosterone and the hormones that act like it.
How to Increase Testosterone If You Want Children (The Options Besides TRT)
If you want children, the aim is to raise your body's own testosterone rather than replace it, and that starts with talking to your prescriber before you change or stop anything. The specialist options, from the EAU male infertility guideline and the BSSM:
- hCG, which acts like LH. In a small series of 26 men on TRT plus hCG, none ended up with zero sperm and 9 contributed to a pregnancy (Hsieh et al., 2013).
- Clomifene (a SERM), which the BSSM says raises testosterone without a negative impact on fertility. A related drug, enclomiphene, kept sperm counts normal in overweight men with low testosterone, where testosterone gel did not (Kim 2016).
- Freezing sperm first. A 2022 review by Imperial Healthcare NHS Trust andrologists sees some merit in discussing it before starting TRT, and the HFEA suggests considering it before treatment that may affect fertility (see our UK sperm freezing guide).
Both are off-label in the UK for this: the BSSM lists hCG as off-label, and the UK clomifene licence covers ovulatory failure in women.
A semen analysis first shows where you actually stand.
Dr Rena Malik, a urologist, covers how TRT can cause fertility loss and how hCG can help preserve it in this video.
Do Anabolic Steroids Cause Infertility? (The Gym Side of This)
Yes, anabolic steroids can cause infertility, through the same switch-off as TRT but without a doctor keeping an eye on it. The NHS lists reduced sperm count, infertility and shrunken testicles among the effects in men, and its infertility causes page says: "long-term misuse of anabolic steroids can reduce sperm count and sperm mobility".
The Society for Endocrinology (2026) cites an estimate that around 500,000 men in the UK have used non-prescribed androgens, and says the evidence for "post-cycle" drugs is limited and of low quality.
Recovery is real but slow: 14.1 months on average for sperm output in the Australian study. The EAU says sperm usually improve over six to 12 months after stopping.
What Counts as Low Testosterone in the UK?
In UK (BSSM) and European guidance, low testosterone generally means a total testosterone under 12 nmol/L on two separate morning blood tests, alongside symptoms. The BSSM treats 8 to 14 nmol/L as a grey zone where a trial of at least six months may be considered, based on symptoms. NICE's GP guidance on assessing erectile dysfunction says to test a fasting total testosterone between 9 and 11am, repeated with FSH, LH, SHBG and prolactin if it's low or borderline (NICE CKS).
My 17.0 sat comfortably above that 12 nmol/L line, a level the BSSM says doesn't call for treatment.
The BSSM's key symptoms are low sex drive, fewer morning erections and erection problems; it calls tiredness and low mood less specific. The NHS says testosterone falls by about 1% a year from around 30 to 40, and that late-onset hypogonadism is uncommon and not a normal part of ageing.
How to Naturally Increase Testosterone (Without Touching Your Sperm)
The best-evidenced way to naturally increase testosterone is losing weight if you're carrying extra. Better sleep and regular exercise help too, and cutting back on heavy drinking protects semen quality. Unlike testosterone from outside, these aim to help your body make more of its own, which is sort of the whole point.
- Weight loss. A meta-analysis of 24 studies found diet and bariatric surgery both raised total and free testosterone, more so with more weight lost. The EAU calls it the first approach for overweight men with low testosterone.
- Sleep. One week of five-hour nights cut daytime testosterone by 10 to 15% in 10 healthy young men (JAMA, 2011). Tiny study, but a pretty clear signal.
- Exercise. The EAU says physical activity gives similar results to diet, though the rise is small, about 1 to 2 nmol/L.
- Alcohol. NICE says excessive alcohol harms semen quality, while staying within 14 units a week, spread over several days, is unlikely to affect it. More in our alcohol and fertility guide.
I went from 105kg to 85kg myself, roughly a fifth of my body weight (here's how it went).
It's the boring basics, done consistently for months.
Do Testosterone Boosters Actually Work? (Mostly, No)
Most over-the-counter testosterone boosters don't raise testosterone, and they're mostly vitamins, minerals and herbs rather than testosterone itself. A 2024 systematic review of 52 studies covering 27 proposed boosters concluded that most fail to increase total testosterone.
A review of 50 booster products found 109 ingredients, 67 of them (61.5%) not tested for testosterone in any study the authors could find. Searching "testosterone supplement" instead, the same authors found products containing actual hormone.
- Zinc: more isn't better. The NHS says no more than 25mg of zinc supplements a day unless a doctor advises it. I was taking 100mg at one point, so I'm really not judging anyone.
- Ashwagandha, fenugreek, maca and shilajit were all among the 14 supplements I took. My real results article grades the evidence for all four Weak, and the 2024 review rated ashwagandha, the best studied of the four, only "possibly effective" for testosterone in healthy men.
These reviews measured testosterone, not sperm, so they say little about fertility.
When Should You See a GP?
See a GP if you've been trying to conceive for a year, or sooner if you already know there may be a fertility problem. That's NHS advice, which also says women aged 36 and over should go sooner. Being on TRT or steroids is a good reason to go sooner.
- On prescribed TRT and want children: speak to your prescriber before changing or stopping anything.
- Symptoms of low testosterone: your GP may test you and refer you to an endocrinologist.
- Steroid dependence: see a GP. Stopping suddenly can bring withdrawal symptoms, including depression.
- A lump or change in a testicle: urgent GP or NHS 111. Sudden, severe pain in a testicle, testicle pain along with feeling sick, being sick or pain in your tummy, or testicle pain that has lasted more than an hour or continues when you're resting: A&E or 999 (NHS).
- Chest pain that feels tight or like squeezing on your chest, or chest pain that's spreading to your arms, neck or jaw: call 999 (NHS). Heart attack is a listed steroid risk.
Frequently Asked Questions
Does taking testosterone make you infertile?
It usually suppresses fertility while you take it, sometimes completely, by switching off LH and FSH, the hormones that drive sperm production. In a 1990 WHO trial of healthy men on weekly injections, 65% had no sperm at all by six months. European urology guidelines advise against it for men who want to be fathers.
Is infertility from testosterone reversible?
Usually, yes. In contraceptive trials of 1,549 healthy men, sperm returned to 20 million/mL in 67% within six months and 90% within 12. The UK's BSSM guideline gives a lower figure for younger men on testosterone therapy: reversible in 60 to 70% within 12 months. Recovery after years of TRT or steroids is harder to predict.
Can you have a baby while on TRT?
It's possible but unreliable, and guidelines advise against TRT for men trying to conceive. In a 1996 WHO trial, men suppressed to 0.1 to 3 million/mL had 8.1 pregnancies per 100 person-years and men with no sperm had none; an earlier WHO trial recorded one pregnancy in about 124 person-years at zero sperm. Some specialists add hCG to keep sperm going, based on small studies.
Do testosterone boosters affect fertility?
Most boosters don't contain testosterone and mostly don't raise it: a 2024 review of 27 found most fail to increase total testosterone. They measured testosterone, not sperm, so they say little about fertility. The NHS advises keeping zinc supplements to 25mg a day or less.
Something You Go Through Together
Testosterone can feel awkward to bring up, especially if you're the partner wondering about his TRT or his gym habits.
It's OK to ask the awkward question. Most of this is reversible, and like everything else with trying to conceive, it's something you go through together.
Keep Reading: Helpful TTC Guides
For the male side of things, start here:
- How to Improve Sperm Quality Naturally (Real Results After 6 Months)
- Male Fertility Screening: What to Expect From a Sperm Test
- Sperm Freezing in the UK: The Real Process, Costs and What to Expect
- Does Alcohol Affect Fertility?
