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How to increase sperm count: every factor ranked by evidence
Smoking, weight, heat, alcohol, sleep, diet, exercise, stress, caffeine, supplements, timing and age, ranked by evidence, with effect sizes and timeframes.
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How to read semen analysis results: WHO 2021 reference limits explained
Every semen analysis number with its WHO 2021 lower reference limit, what below reference means, why one test is not a verdict, and when to see a urologist.
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One habit at a time
Does age affect male fertility? What changes after 35, 40 and 45
Semen volume, motility and morphology decline with age in a meta-analysis of 90 studies; men over 45 took longer to conceive; risks for the baby rise a little.
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Does alcohol affect sperm? What the studies found
Heavy and daily drinking is linked to lower semen volume, count and morphology; occasional drinking isn't. The dose curve, and how long cutting back takes.
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Does caffeine affect sperm? Coffee, tea, cola and energy drinks
Coffee and tea in ordinary amounts aren't linked to poorer semen quality in a review of 28 studies; a liter of cola a day was. The numbers and the caveats.
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Cannabis and sperm: what the studies actually found
Frequent cannabis use is linked to lower sperm counts in a large study of young Danish men, but other studies disagree. What the evidence shows.
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What to eat for sperm health: the diet patterns with evidence
Which foods have evidence behind them and which do not, food by food, with effect sizes. Plus what the 2,935-man Danish study and the nut trials actually found.
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How often should you ejaculate when trying to conceive?
ASRM supports sex every 1 to 2 days in the fertile window; the NHS says every 2 to 3 days. What daily ejaculation does to a sample, and why saving up is no help
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Does exercise affect sperm? Moderate activity, hard training and cycling
Active men have better semen quality in a 2019 meta-analysis; five-plus hours a week of cycling doubled the odds of a low count in one study.
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Does heat affect sperm? Saunas, hot tubs, laptops, underwear, cycling
What the sauna, hot tub, laptop, underwear and cycling studies measured, how big the effects were, and how quickly sperm recovered once the heat stopped.
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How long does it take to improve sperm quality? About 74 days
About two to three months: one cycle of sperm production takes roughly 74 days. Where the figure comes from, which changes show fastest, and when to retest.
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How to improve sperm morphology: what the evidence shows
What sperm morphology means, why the WHO limit is 4%, how much it matters for pregnancy, and which habits are linked to better results.
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How to improve sperm motility: what the evidence supports
What motility means on a semen report, the WHO 2021 limits (42% total, 30% progressive), and the changes linked to better motility, with effect sizes.
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Low sperm count: causes and what to do next
What a low sperm count means against the WHO 2021 limit of 16 million per mL, what causes it, what the evidence says helps, and when to see a specialist.
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Male infertility statistics: the key numbers, with sources (2026)
How common infertility is, how often a male factor is involved, the sperm count decline debate, and the WHO 2021 limits. Every figure linked to its source.
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Microplastics and sperm: what the research shows, and what it doesn't (2026)
Microplastics are in semen, testes and blood. What the human studies can and can't say about sperm, how to cut exposure, and why Motily doesn't score it.
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Do phones, laptops and Wi-Fi affect sperm? What the evidence says
A WHO-commissioned review calls the phone evidence very uncertain and found little effect from a pocket. Laptops matter for heat. What the studies show.
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Does sleep affect sperm? The two best studies explained
Disturbed sleep and both short and long nights are linked to lower sperm counts in two large studies. What they found, why, and what 7 to 8 hours looks like.
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Does smoking or vaping affect sperm? Two meta-analyses and the vaping study
Smokers have lower sperm count, motility and morphology in meta-analyses of 16,000 men; daily vapers had lower counts in one large study. What quitting does.
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Sperm DNA fragmentation: what the test shows and who needs it
A sperm DNA fragmentation test measures broken DNA in sperm. NICE says don't test; US and European guidelines do after recurrent miscarriage.
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How to get a sperm test in the UK: NHS, private clinics and home kits
The NHS route via your GP, NICE's timing, private clinics from £189, home kits from £39, a UK mail-in lab test from £180, and how to give a good sample.
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Does stress affect sperm? What the studies found, and what they didn't
Two or more stressful life events were linked to poorer semen quality in studies of 193 and 744 men; moderate stress showed no clear effect. Mixed evidence.
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Do supplements improve sperm? CoQ10, zinc, folate, vitamin D, omega-3
The 2022 Cochrane review calls the evidence inconclusive and the two biggest trials were negative. What each ingredient's trials found, and why food wins.
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Does testosterone (TRT) affect fertility? Sperm, steroids and recovery
TRT and anabolic steroids switch off sperm production, often to zero. What the guidelines say, how long recovery took in 1,549 men, and what to ask a doctor.
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Varicocele and fertility: what repair does and does not do
A varicocele is found in about 15% of men. What it does to semen, what repair improves, and why the live birth evidence is rated very low certainty.
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Does weight affect sperm? BMI, weight loss and the trial that measured it
Obesity is linked to higher odds of a low sperm count in a meta-analysis of 13,077 men; an eight-week weight-loss trial raised counts 1.4-fold. What holds up.
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When to repeat a semen analysis: the three-month rule explained
NICE says repeat an abnormal semen analysis about 3 months later, sooner if no sperm were found; the AUA says two a month apart. Why, and how to compare them.
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Tools and reference
Semen analysis checker
Type in the numbers from a report and see each one against the WHO 2021 lower reference limit.
74-day timeline
Pick a start date and see when a change in habits can first show in a semen analysis.
Glossary
Forty terms from a semen analysis report and the fertility clinic, defined in plain English.
The science page
The 74-day cycle and a one-page summary of the evidence across all the habits.
Motily is a lifestyle and wellbeing tool, not a medical device. These pages summarise published research and never diagnose. If a semen analysis is below the reference limits, or you have been trying for a year (six months if your partner is 35 or over), see a GP or a urologist.
