Heat is shown to lower sperm count. NUMBNUTS keeps you cool, in the sauna or as a daily ritual. Founder preorder ships Sep 2026. Reserve Launch Kit

Cooling 101

Heat, cooling, and your fertility

Plain-English guides on how heat affects men, what the research really says, and the simple ways to keep cool. Educational, not medical advice.

How to Protect Your Sperm From Heat: The Simple Guide Heat is bad for sperm, but what do you actually do about it? The complete, simple version: find your heat sources, then reduce them or cool them. Summer Heat and Your Sperm: The Seasonal Dip Nobody Mentions Sperm quality tends to dip in summer. If you are trying to conceive, the season is quietly part of the equation. Here is the pattern and what to do... Hot Tubs, Hot Baths and Male Fertility Hot water is one of the most effective ways to overheat the testicles. Here is the honest picture for fertility, and how to keep the soak you love ... Does Tight Underwear Affect Sperm? Boxers vs Briefs The oldest fertility advice going: wear loose boxers. Is there anything to it? Yes, a little, and it is the easiest change on the list. Here is the... Is Your Laptop Cooking Your Sperm Count? A laptop on your lap is one of the most common modern heat sources, and one of the easiest to fix. Here is what it does to scrotal temperature and ... Trying to Conceive: The Male-Factor Checklist Male factors are involved in about half of couples trying to conceive, and much of it is controllable. A calm, practical checklist, with heat as th... Should You Ice Your Testicles? What's Real and What's Hype Icing your testicles is having a moment. The honest version: what cooling is actually supported to do for sperm, the testosterone claim that is not... Does Sauna Affect Sperm Count? What the Research Actually Says Yes, sauna heat is linked to a temporary dip in sperm count and motility. Here is what the research shows, how long recovery takes, and how to keep...