Coffee and tea in ordinary amounts don't appear to affect semen quality; heavy cola drinking does, and probably not because of the caffeine. A 2017 systematic review of 28 observational studies covering nearly 20,000 men found semen quality was not affected by caffeine from coffee, tea or cocoa in most studies, while cola and other caffeinated soft drinks were linked to lower volume, count and concentration. In a 2010 study of 2,554 young Danish men, those drinking more than 14 half-liter bottles of cola a week had a sperm concentration of 40 million per mL against 56 million in non-drinkers, and a total count of 121 million against 181 million, while caffeine intakes between 101 and 800 mg a day showed no association at all. The European Food Safety Authority puts 400 mg a day, about four cups of filter coffee, within the safe range for healthy adults.
Coffee and tea
Ricci and colleagues (Nutrition Journal, 2017) reviewed 28 studies of caffeine and male fertility. Across them, coffee, tea and cocoa were not linked to lower volume, count, concentration, motility or morphology in most of the studies that measured them. A few studies reported links between caffeine and sperm DNA damage or chromosome abnormalities, and the review notes them, but the findings were inconsistent between studies and the authors called the overall evidence inconclusive. The Danish study above tells the same story at the population level: men on moderate caffeine, up to 800 mg a day, looked no different from men on almost none. Men on very high intakes (over 800 mg a day, more than eight cups of coffee) had somewhat lower concentrations and counts in that study, but the difference was not statistically significant, and the men drinking that much differed in other ways too.
Cola and other soft drinks
Jensen and colleagues (American Journal of Epidemiology, 2010) studied 2,554 Danish men aged around 19 at their military examination. Men who drank more than 14 half-liter bottles of cola a week, roughly a liter a day, had a sperm concentration of 40 million per mL against 56 million in men who drank none, and a total count of 121 million against 181 million. Two things stood out. The cola drinkers also ate more fast food and less fruit and vegetables, so the finding travels with a whole pattern. And the amount of caffeine in that much cola was modest compared with coffee, which is why the authors wrote that the effect "could not be attributed to the caffeine". A separate 2014 study of 189 young American men found those drinking 1.3 or more sugar-sweetened drinks a day had progressive motility about 10 percentage points lower. Sugar and diet pattern, not caffeine, are the likelier culprits; the diet guide covers them.
Energy drinks
There is no good sperm-specific study of energy drinks to cite, so this section is inference. EFSA's figure is about 80 mg of caffeine per 250 mL can, roughly an espresso, and the sugar in a standard can is in the same league as a cola, which puts energy drinks in the cola category for sugar and in the moderate range for caffeine. The soft-drink findings above are the closest evidence, and they point at the sugar. Treat energy drinks as sugary drinks with caffeine in them.
How much caffeine is in what
The European Food Safety Authority's 2015 opinion is that up to 400 mg a day, spread across the day, raises no safety concern for healthy adults, and a single dose of up to 200 mg is fine at once. EFSA's own serving figures: a 200 mL cup of filter coffee about 90 mg, so four cups is close to the daily figure; a 60 mL espresso about 80 mg; a 220 mL cup of black tea about 50 mg; a 355 mL can of cola about 40 mg; a 250 mL energy drink about 80 mg. Those figures are general safety guidance, not fertility findings, but they line up with where the fertility studies stopped seeing anything.
Caffeine and sleep
The one route by which ordinary caffeine could plausibly affect sperm is sleep. Caffeine taken in the late afternoon or evening delays and fragments sleep for many people, and disturbed sleep is linked to lower sperm concentrations in a study of 953 men. If you drink coffee, the timing may matter more than the amount; the sleep guide has that evidence.
How long until a change shows
If cutting back on sugary drinks changes anything, it does so through the production cycle of about 74 days, so allow two to three months before a semen analysis reflects it. Coffee and tea at ordinary levels are not a change you need to make for sperm.
What to do
- Keep coffee and tea. Two or three cups a day sit well inside the range where the studies found nothing.
- Move the last cup to before mid-afternoon so it doesn't cost you sleep, which has its own evidence.
- Cut cola, energy drinks and other sugary drinks; that is the finding with numbers attached, and it belongs to diet as much as to caffeine.
- If you are well over 800 mg a day (eight-plus cups), bring it down, for reasons that go beyond sperm.
- Log it honestly in the app. Motily scores up to two or three cups as neutral and only nudges above that.
Related guides
Sources
- Ricci E, et al. Coffee and caffeine intake and male infertility: a systematic review. Nutrition Journal, 2017.
- Jensen TK, et al. Caffeine intake and semen quality in a population of 2,554 young Danish men. American Journal of Epidemiology, 2010.
- Chiu YH, et al. Sugar-sweetened beverage intake in relation to semen quality and reproductive hormone levels in young men. Human Reproduction, 2014.
- European Food Safety Authority. Scientific opinion on the safety of caffeine. 2015.
- Heller CG, Clermont Y. Spermatogenesis in man: an estimate of its duration. Science, 1963.