Questions men actually ask.

Roughly two to three months. New sperm are made continuously in a process called spermatogenesis, and the classic estimate of its duration in men is about 74 days from stem cell to sperm, followed by one to two weeks of maturing in the epididymis. A 2006 study using a stable-isotope tracer measured about 64 days from labeled stem cell to ejaculated sperm, spermatogenesis and epididymal transit together, which is why Motily talks about the timing as rough rather than exact.

Either way, a change you make today, such as cutting back on drinking or fixing your sleep, takes about two to three months to show up in the sperm you actually produce. That's why Motily's journey runs for 74 days, and why a semen analysis taken a week into a new routine mostly reflects the old one. The how-long guide goes through the two studies, and the 74-day timeline tool gives the retest date.

Sources: Heller CG, Clermont Y. Kinetics of the germinal epithelium in man. Recent Progress in Hormone Research, 1964. Misell LM, et al. A stable isotope-mass spectrometric method for measuring human spermatogenesis kinetics in vivo. Journal of Urology, 2006.

Research suggests it does. A study of 953 young Danish men found that those reporting the most sleep disturbance had sperm concentrations around 29% lower than men with little disturbance, and a longitudinal Chinese study found an inverse U shape: both short (6.5 hours or less) and long (over 9 hours) sleep were linked to lower semen volume and sperm number than 7 to 7.5 hours. Around 7 to 8 hours a night, at a consistent bedtime and wake time, is generally considered the sweet spot.

These are observational studies, so they show a link rather than proof of cause. Motily scores sleep on hours and asks about quality, and can prefill the hours from Apple Health. The sleep guide has both studies in detail.

Sources: Jensen TK, et al. Association of sleep disturbances with reduced semen quality: a cross-sectional study among 953 healthy young Danish men. American Journal of Epidemiology, 2013. Chen Q, et al. Inverse U-shaped association between sleep duration and semen quality: longitudinal observational study (MARHCS) in Chongqing, China. Sleep, 2016.

Heavy or daily drinking is linked to lower semen volume and poorer sperm quality. Light to moderate drinking shows less clear effects: a 2017 systematic review and meta-analysis found the consistent association was with daily or heavy intake rather than occasional drinks.

Motily scores each day's alcohol on a sliding scale, so an alcohol-free day scores full points, one drink costs a little, and four or more costs the most. A few extra alcohol-free days a week is the simplest change. Caffeine is scored separately, and moderate intake (up to two or three cups) isn't penalized, because a 2017 review didn't find a consistent link between coffee and semen quality. The alcohol guide has the dose curve.

Sources: Ricci E, et al. Semen quality and alcohol intake: a systematic review and meta-analysis. Reproductive BioMedicine Online, 2017. Ricci E, et al. Coffee and caffeine intake and male infertility: a systematic review. Nutrition Journal, 2017.

Smoking, yes, and it's one of the most consistently confirmed lifestyle factors. A 2016 meta-analysis of more than 5,000 men found smokers had lower sperm count, lower motility and poorer morphology, with the effect strongest in moderate and heavy smokers. There's no safe amount, so Motily scores even light smoking steeply. Quitting entirely is one of the single biggest wins available to you.

Vaping has far less research behind it. One 2020 study of young Danish men, in which 1,221 reported on e-cigarette use and only 25 vaped daily, found daily e-cigarette users had lower total sperm counts than non-users, but it's a single observational study and the picture is still forming. Motily treats vaping as a substance to log, and is honest that the evidence is thinner than for cigarettes. The smoking and vaping guide has the numbers.

Sources: Sharma R, et al. Cigarette smoking and semen quality: a new meta-analysis examining the effect of the 2010 World Health Organization laboratory methods for the examination of human semen. European Urology, 2016. Holmboe SA, et al. The association of reproductive hormones with sperm quality and e-cigarette and marijuana use in young men. Human Reproduction, 2020.

Extra heat around the testicles can temporarily lower sperm production, and the effect is generally reversible once the exposure stops. In a small 2013 study, two 15-minute sauna sessions a week for three months reduced sperm count and motility in ten healthy men, and both were back to baseline by the six-month follow-up.

On underwear, a 2018 study of 656 men attending a fertility center found those who mostly wore boxers had higher sperm concentration and total count than those who mostly wore tighter styles. Motily asks each day which heat exposures applied, and the best answer is none of them. Simple swaps, like a lap desk and looser, breathable underwear, are permanent fixes. The heat guide covers each exposure and how quickly sperm recovered.

Sources: Garolla A, et al. Seminal and molecular evidence that sauna exposure affects human spermatogenesis. Human Reproduction, 2013. Mínguez-Alarcón L, et al. Type of underwear worn and markers of testicular function among men attending a fertility center. Human Reproduction, 2018.

Research suggests a sweet-spot effect. A 2019 systematic review and meta-analysis of 32 studies found that most results pointed to no major effect of physical activity on semen quality, though recreational activity may be linked to better sperm concentration and progressive motility, while elite-level training and cycling were linked to poorer results on some measures. Moderate and regular beats none or extreme.

Motily's daily target is 25 to 45 minutes of moderate activity, and it scores a very long single session slightly below that band rather than penalizing it, because the overtraining concern is really about sustained weekly volume. If you're currently sedentary, a daily walk is a legitimate starting point.

Source: Ibañez-Perez J, et al. An update on the implication of physical activity on semen quality: a systematic review and meta-analysis. Archives of Gynecology and Obstetrics, 2019.

It appears to. A 2013 collaborative meta-analysis of 21 studies and 13,077 men found that men in the overweight and especially the obese BMI range were more likely to have a low sperm count or no sperm at all than men of normal weight; underweight men showed a small rise that was not statistically significant.

Motily uses your height and weight from the onboarding quiz to include BMI in your Motily score, and its tip is gradual, sustainable change toward a healthy range rather than quick fixes. The guide to increasing sperm count ranks weight against the other factors.

Source: Sermondade N, et al. BMI in relation to sperm count: an updated systematic review and collaborative meta-analysis. Human Reproduction Update, 2013.

Probably, though the evidence is mixed. A 2014 study found men reporting two or more stressful life events in the past year had lower motility and morphology, but a 2016 study of 1,215 Danish men found self-rated stress was linked to lower semen quality only above a moderate level, most clearly at the highest stress levels. The proposed mechanism runs through stress hormones like cortisol affecting testosterone.

This is about general wellbeing trending the right way, not any single stressful day, and eliminating stress entirely isn't realistic for most people. Motily asks how many stressful episodes you had and how you felt. The things that tend to help most are small and repeatable: a short walk, a few minutes of breathing, stepping outside. Regular exercise and consistent sleep both indirectly support mood.

Sources: Janevic T, et al. Effects of work and life stress on semen quality. Fertility and Sterility, 2014. Nordkap L, et al. Psychological stress and testicular function: a cross-sectional study of 1,215 Danish men. Fertility and Sterility, 2016.

More whole, unprocessed food and less ultra-processed food. A 2017 systematic review of observational studies found diets rich in vegetables, fruit, fish, poultry, whole grains and low-fat dairy were linked with better semen quality, while diets high in processed meat, full-fat dairy, sweets and sugary drinks were linked with worse. The nutrient groups worth knowing about: antioxidant-rich foods (berries, walnuts, leafy greens, tomatoes), omega-3s (oily fish, flaxseed), zinc and selenium (oysters, pumpkin seeds, Brazil nuts) and folate (leafy greens, lentils, chickpeas).

Supplements are less clear-cut. The 2022 Cochrane review of antioxidant supplements found they may increase live birth and pregnancy rates in subfertile couples, but rated the evidence very low to low certainty because of risk of bias, poor reporting and small trials. Food first, and check with a clinician before starting supplements, especially alongside medication. Motily's nutrition check-in asks roughly what share of your food was whole, whether you took a supplement, and your caffeine. The supplements guide takes the common ones one at a time.

Sources: Salas-Huetos A, Bulló M, Salas-Salvadó J. Dietary patterns, foods and nutrients in male fertility parameters and fecundability: a systematic review of observational studies. Human Reproduction Update, 2017. de Ligny W, et al. Antioxidants for male subfertility. Cochrane Database of Systematic Reviews, 2022.

More often than folklore suggests. The American Society for Reproductive Medicine's committee opinion says pregnancy rates are highest with intercourse every one to two days during the fertile window (roughly the five days before ovulation plus ovulation day), that two to three times a week gives nearly the same results, and that couples shouldn't save up for one big day.

Frequent ejaculation doesn't harm sperm quality: a 2016 study that had 20 men ejaculate daily for two weeks found volume, concentration and total motile count fell, mostly in the first three days, while motility and morphology were unchanged, and shorter abstinence is linked to healthier sperm DNA in several studies. Most standard lubricants, and saliva, can slow sperm down, so if you need one, choose a fertility-friendly product.

Sources: Practice Committee of the American Society for Reproductive Medicine. Optimizing natural fertility: a committee opinion. Fertility and Sterility, 2022. Welliver C, et al. Analysis of semen parameters during 2 weeks of daily ejaculation: a first in humans study. Translational Andrology and Urology, 2016.

The NHS advises seeing a GP if you haven't conceived after a year of regular unprotected sex, and sooner if your partner is 36 or over or either of you has a known fertility issue. ASRM uses 6 months when the woman is 35 or older. Ask sooner if you have a known factor on your side: a varicocele, an undescended testicle, mumps after puberty, groin or testicular surgery, past chemotherapy or radiotherapy, or testosterone or anabolic steroid use. That's a proactive step, not a sign anything's wrong.

Motily can't do any of this for you. It doesn't diagnose, doesn't treat, and doesn't guarantee any outcome. It's a lifestyle tool, not a medical device, and it hasn't been assessed by any medical regulator. It can't tell you whether you're fertile, and it doesn't replace a semen analysis, a urologist or a fertility specialist.

Sources: NHS. Infertility. Practice Committee of the American Society for Reproductive Medicine. Optimizing natural fertility: a committee opinion. Fertility and Sterility, 2022.

Yes, and in the opposite direction to what people often expect. Testosterone taken from outside the body switches off the hormone signal that drives sperm production, so it lowers sperm count rather than raising it. NICE NG257 says not to offer androgens to treat semen abnormalities, and the AUA guideline says clinicians should not prescribe testosterone to a man interested in current or future fertility. Recovery after stopping is usual but slow: in an analysis of 30 male hormonal contraception trials, the median time for sperm to return to 20 million per mL was 3.4 months, with about 67% of men back at that level by 6 months and 90% by 12. Years of high-dose anabolic steroid use are not the same as those supervised doses, and recovery there is slower and less certain. If you need treatment for low testosterone and want to keep your fertility, there are other options to discuss with a doctor.

Sources: National Institute for Health and Care Excellence. Fertility problems: assessment and treatment (NG257). 2026. Liu PY, et al. Rate, extent, and modifiers of spermatogenic recovery after hormonal male contraception: an integrated analysis. The Lancet, 2006. More in the testosterone and fertility guide.

Three routes. Through the NHS, a GP can refer you for a semen analysis, which is free; availability and waiting times vary by area, and some regions ask you to have been trying for a year first. Privately, a clinic semen analysis is the same test without the wait. At home, a postal kit sends your sample to a lab, and a phone-camera device gives you a count and motility reading at home; the device tests are a screen rather than a full analysis, since they do not measure everything a lab does. Whichever route, the lab's instructions matter as much as the test: 2 to 7 days without ejaculating, the sample kept at body temperature, and delivered within the window the lab gives you. NICE says an abnormal first result should be repeated, usually about three months later.

Sources: World Health Organization. WHO laboratory manual for the examination and processing of human semen, 6th edition. 2021. National Institute for Health and Care Excellence. Fertility problems: assessment and treatment (NG257). 2026. NHS. Infertility. Routes, prices and kits in the UK sperm test guide.

About 1 in 6 people worldwide experience infertility at some point in their lives, on the WHO's 2023 estimate of 17.5% lifetime prevalence. In the WHO's multi-country study of 8,500 couples, a male factor was the only cause in 18.7% of cases and contributed wholly or in part to 45.1%. The AUA gives a similar picture: solely responsible in about 20% of couples, contributory in another 30 to 40%. So a male factor is involved roughly half the time, and is the whole story in about one case in five. Where a low count is found, no cause is identified in 30 to 40% of men, which is the single largest category.

Sources: World Health Organization. Guideline for the prevention, diagnosis and treatment of infertility. 2025. European Association of Urology. Guidelines on Sexual and Reproductive Health: male infertility. 2026. The numbers with their sources are on the statistics page, and causes in the low sperm count guide.

Emerging research suggests they might, in ways beyond sperm count alone. A father's diet, weight, smoking, alcohol use, stress and toxin exposure before conception can alter chemical markers on sperm, such as DNA methylation, that influence how genes switch on and off without changing the DNA sequence itself.

Most of the strongest evidence so far comes from animal studies, with human research still catching up, so treat it as a promising, still-developing picture rather than settled fact, and one more reason the months before conception are worth taking seriously.

Source: Soubry A, et al. A paternal environmental legacy: evidence for epigenetic inheritance through the male germ line. BioEssays, 2014.

A standard semen analysis reports semen volume, sperm concentration, total sperm count, total motility and progressive motility, and often morphology, pH and vitality. The WHO Laboratory Manual for the Examination and Processing of Human Semen, 6th edition (2021), gives lower reference limits taken from the 5th centile of men whose partners conceived within a year:

A result below a limit means below reference, not infertile: plenty of men below these limits have children, and plenty above them don't. Results also vary a lot between samples, which is why clinics often repeat the test. Motily shows each value you enter against these limits and tracks the trend between reports, and leaves interpretation to your clinician. DNA fragmentation and antisperm antibodies aren't WHO reference limits; where the app shows tiers for them it uses commonly cited laboratory cut-offs. The semen analysis guide explains each line of a report, and the checker tool compares your numbers against these limits without sending them anywhere.

Source: World Health Organization. WHO laboratory manual for the examination and processing of human semen, 6th edition. Geneva, 2021.

There are two scores. Today's Motily points are out of 100 and climb as you log the day's eight categories, weighted roughly by how strong and consistent the research is for each: nutrition 18, substances 18, sleep 16, exercise 12, heat 10, mood and stress 10, intercourse 10, hydration 6.

Your Motily score starts from your onboarding quiz (which also includes age, BMI, underwear and sitting time) and blends each overlapping category 50/50 with the average of your last seven days, so recent behavior counts as much as your baseline without a single day swinging it.

Both are estimates built from what you tell the app. Neither is a measure of your fertility, and neither can tell you whether you can or cannot conceive.

Once you've done the day's check-in, Motily gives you three statements about sperm health. Call each one myth or fact, then see the answer with a one-line explanation and its source. It takes under a minute, and a puzzle streak counts the days in a row you play.

One question a day about your own habits, also unlocked by your check-in, such as how often you have sex when you're trying to conceive. Your answer shows what the research links that habit to, with the number and the source behind it, and one thing to try where there is one. Every answer is kept under See all your findings, the things to try feed Next steps on Home, and new questions unlock as you move through the 74 days.

Yes. The Analysis and Journey screens show a card for ExSeed's CE-marked home test kit, which opens ExSeed's shop. Motily sells nothing itself; the link is an affiliate link, so Motily earns a commission if you buy, at no extra cost to you, and code MOTILY gives 10% off (not on subscriptions). A home test is not a diagnosis: if you've been trying for 12 months, see your GP. If you test with ExSeed, you can add its downloaded report and the app reads the results from it on your phone. The at-home tests comparison covers the alternatives.

Almost everything Motily stores about you is health data, and some of it concerns your sex life, so it's treated as special category data under UK GDPR and processed only with your explicit consent. It's stored with Supabase in its London region, every table is protected by row-level security, and no advertising SDKs, ad identifiers, location or cross-app tracking are used. Motily doesn't sell your data. A crash reporter (Sentry, EU region) and a usage counter (PostHog, EU cloud) help keep the app working, and neither ever receives your answers, scores or report values; the usage counter can be switched off in Profile. You can delete your account and everything tied to it yourself, immediately, from Profile. Read the full privacy policy.

Your partner sees only what you choose to share, and never your answers. The partner page needs no app and no account: she opens a link, enters the 6-character code from your Profile, and sees which day of the 74-day journey you're on, your streak and Perfect Days, and whether today's check-in is done. She can send a nudge that shows up in your app. She can't see your score, your check-in answers, your quiz answers, your semen analysis or your Community identity, and the read path is a whitelist enforced on the server. Either of you can disconnect at any time. Optionally, and with clear consent, she can share her last period date and cycle length so her fertile window shows on your Today tab; that part is Premium.

During the launch period, nothing. Every Premium feature is free for everyone, choosing a plan unlocks it at no cost, and no payment details are collected. Free always includes daily check-ins, your Today's Motily points and Motily score, streaks, the 74-day journey, your first semen analysis interpreted, the partner page and Community. The planned Premium prices after the launch period are £8.99 a month or £54.99 a year, and Premium adds the score breakdown, trends beyond this week, interpretation of every semen analysis you log, the partner fertile-window sync and, soon, a weekly report. If paid plans arrive, you'll hear about it in the app first, with notice, and payments would go through the App Store.

Motily measures nothing itself. Where we link to a test made by someone else, we label it, and some of those links earn us a commission, at no extra cost to you. There are no ads and no data selling.

Motily is iPhone only, from the App Store, and Apple Health prefill is iOS only too. The partner page is a website, so a partner on Android can use it today. If you want Motily on Android, email hello@motily.app and say so; it helps decide what comes next.