Short answer
Start around 12 weeks before treatment if you can. Sperm take roughly two months to develop, so the sample collected on the day began forming weeks earlier. With that time, the steps with the best evidence are stopping smoking, keeping alcohol within 14 units a week, working towards a healthier weight, avoiding heat, and talking to your doctor about any testosterone or steroids. With six weeks, or even two, there's still useful work to do. None of this has been shown to change IVF success rates. It takes known stresses off sperm production, which is the part in your hands.
If you're reading this ahead of IVF or ICSI, you're probably carrying a lot already. So here's a plain plan for whatever time you've got.
How long does it take to make new sperm?
Roughly two months. A classic tracer study estimated the whole process at about 64 days (Heller and Clermont, 1963). A more recent one found newly made sperm first appeared in the ejaculate after 64 days on average, ranging from 42 to 76 days between men (Misell et al., 2006). Our guide to how long sperm take to regenerate explains the timeline.
What can you do with 12 weeks or more?
This is a full production run, so the sperm made from today are the ones likely to be collected.
- Stop smoking. Across 20 studies and 5,865 men, smoking was linked with lower sperm count, motility and normal shape, more so in heavier smokers (Sharma et al., 2016). NICE notes the impact on fertility itself is uncertain, but stopping helps your general health. The NHS offers free support.
- Take a break from cannabis. In 1,215 young Danish men, smoking it more than once a week was linked with 28% lower sperm concentration (Gundersen et al., 2015).
- Keep alcohol within 14 units a week, spread over several days. NICE says that level is unlikely to affect semen quality, while excessive drinking harms it.
- Work towards a healthier weight. NICE says men with a BMI of 30 or over have a higher risk of reduced fertility, and obesity is linked with more cases of low or zero sperm counts (Sermondade et al., 2013). Whether losing weight improves sperm hasn't been settled, so aim for steady changes your GP would back.
- Pause saunas and hot tubs. Ten men who had two 15-minute saunas a week for three months saw sperm count and motility fall, then recover within six months of stopping (Garolla et al., 2013). Our hot tubs and baths guide covers the rest.
What if you take testosterone or steroids?
If your testosterone is prescribed, please don't stop it on your own. Prescribed or not, raise it with a doctor now. Testosterone from outside the body can shut down sperm production.
WHO Task Force, 1990: 271 men on weekly testosterone
What the research found: Healthy, fertile men given weekly testosterone injections as a trial contraceptive reached zero sperm at a cumulative rate of 65% within six months. After stopping, it took a median of 3.7 months to recover to 20 million per ml (WHO, 1990).
What it doesn't prove: These were healthy volunteers on a set dose, not men on prescribed TRT. Your own picture depends on dose, duration and why you take it.
In pooled contraceptive trials, recovery took up to two years for some men (Liu et al., 2006), and recovery after anabolic steroids ranges from months to years (Solanki et al., 2023). NICE asks clinicians to check for testosterone therapy and anabolic steroids, and advises against using androgens to treat semen problems. Tell your prescriber and your clinic. Nobody will judge you, and it's exactly what they need to know.
What if you only have six weeks?
Those sperm are already in production, but the later stages are still sensitive.
Carlsen et al., 2003: fever and sperm
What the research found: Twenty-seven healthy men gave monthly samples for 16 months. A fever during the later stages of sperm development cut sperm concentration by 35%, and more days of fever meant a bigger drop (Carlsen et al., 2003).
What it doesn't prove: The effect varied a lot between men, and it tends to pass. In one detailed case, sperm count was back to normal 79 days after a two-day fever (Sergerie et al., 2007). You can't always avoid a bug, but you can tell your clinic.
At six weeks: cut the big heat sources, stop smoking and cannabis, and don't start new supplements without telling the clinic.
What can you still do two weeks before?
Too short to remake a batch. Not too short to avoid a knock.
- Skip saunas, hot tubs and long hot baths, and keep the laptop off your lap.
- Follow the clinic's abstinence instructions exactly.
- Tell them about any fever, illness or new medicine, including over-the-counter ones.
- Book the time off and plan how you'll get there, so the day itself is one less thing.
Do supplements improve sperm before IVF?
Schisterman et al., 2020: 2,370 couples
What the research found: Men planning fertility treatment took daily folic acid and zinc, or a placebo, for six months. Live birth rates were the same (34% vs 35%), most semen measures didn't change, and sperm DNA fragmentation was slightly higher in the supplement group (Schisterman et al., 2020).
What it doesn't prove: It tested one popular combination, not every product on the shelf.
NICE now advises against offering supplements or antioxidants to improve sperm DNA fragmentation. Ask your clinic before you spend.
How do you look after yourself through this?
Feeling awkward, anxious or flat is normal. The HFEA has a page on getting emotional support, and UK clinics licensed by the HFEA must offer you the chance to talk to a counsellor before treatment starts. Our male-factor checklist has questions worth taking to appointments. If heat is part of your week, the free five-question Heat Check shows where. It's an educational quiz, not a fertility test. Every source we cite is in our research hub.
Frequently asked questions
Can sperm quality improve in two weeks?
Not by making a new batch. You can still avoid heat, follow the clinic's instructions and report any fever.
Should I stop drinking before IVF?
NICE says up to 14 units a week, spread out, is unlikely to affect semen quality. Ask your clinic what they recommend.
Should I stop TRT before IVF?
Not on your own. Talk to your prescriber and clinic as early as possible, as recovery can take months.
Do fertility supplements for men work?
In the largest trial, folic acid and zinc made no difference to live births.
References
- NICE. Fertility problems: assessment and treatment (NG257), published 31 March 2026, replacing CG156. nice.org.uk
- Heller CG, Clermont Y. Spermatogenesis in man: an estimate of its duration. Science, 1963. PMID 13953583
- Misell LM et al. A stable isotope-mass spectrometric method for measuring human spermatogenesis kinetics in vivo. J Urol, 2006. PMID 16406920
- Sharma R et al. Cigarette smoking and semen quality: a new meta-analysis. Eur Urol, 2016. PMID 27113031
- Gundersen TD et al. Association between use of marijuana and male reproductive hormones and semen quality. Am J Epidemiol, 2015. PMID 26283092
- Sermondade N et al. BMI in relation to sperm count: an updated systematic review and collaborative meta-analysis. Hum Reprod Update, 2013. PMID 23242914
- Garolla A et al. Seminal and molecular evidence that sauna exposure affects human spermatogenesis. Hum Reprod, 2013. PMID 23411620
- WHO Task Force. Contraceptive efficacy of testosterone-induced azoospermia in normal men. Lancet, 1990. PMID 1977002
- Liu PY et al. Rate, extent, and modifiers of spermatogenic recovery after hormonal male contraception. Lancet, 2006. PMID 16650651
- Solanki P et al. Recovery from anabolic steroid-induced hypogonadism: a scoping review. Endocr Connect, 2023. PMID 37855241
- Carlsen E et al. History of febrile illness and variation in semen quality. Hum Reprod, 2003. PMID 14507826
- Sergerie M et al. High risk of temporary alteration of semen parameters after recent acute febrile illness. Fertil Steril, 2007. PMID 17434502
- Schisterman EF et al. Effect of folic acid and zinc supplementation in men on semen quality and live birth. JAMA, 2020. PMID 31910279
Last reviewed 24 September 2026.
