The NUMBNUTS Journal / Know your nuts
Heat. Plastic. Your nuts.
Straight answers.
Heat. Underwear. Male fertility. Understand the research, question the claims, and make more informed choices.
GUIDE 01Do Microplastics Affect Sperm? What Studies of Testicles and Semen Actually FoundMicroplastics have been found in human testicles, semen and follicular fluid, and a few studies link more plastic with poorer sperm ...Read the guide →GUIDE 02Merino vs Cotton vs Polyester Underwear: Which Is Best for Heat and Comfort?For heat, fit matters more than fabric. Roomier underwear is linked with slightly better sperm counts in some studies, but no fibre ...Read the guide →GUIDE 03How Can You Improve Sperm Quality Before IVF or ICSI? What Helps in 2, 6 or 12 WeeksSperm take roughly two months to develop, so changes made 12 weeks before IVF or ICSI shape the sample collected. The best-evidenced...Read the guide →GUIDE 04Are Heated Car Seats Bad for Sperm? What the Studies Actually MeasuredHeated car seats warm the scrotum slightly: in one experiment, 90 minutes on a heated seat left it about half a degree warmer than a...Read the guide →GUIDE 05Do Cold Plunges, Ice Baths or Cold Showers Boost Sperm or Testosterone?No. There's no good evidence that cold plunges, ice baths or cold showers raise sperm count or testosterone. The cooling studies peo...Read the guide →
GUIDE 06Does Polyester Underwear Lower Sperm Count?
THE SHORT ANSWER
There is not strong clinical evidence that wearing everyday polyester underwear lowers sperm count. Polyester is a...Read the guide →
GUIDE 07Spermmaxxing: What Actually Works, and What Is Just DangerousHeat, cooling and underwear: what spermmaxxing research supports, where the evidence is limited, and the questions worth asking.Read the guide →
GUIDE 08The 74-Day Rule: How Long Sperm Takes to Regenerate — and What You Can Change TonightSperm regenerate on a roughly 74-day cycle. Here is what the published research says about heat, fabric and timing — and the two inp...Read the guide →
GUIDE 09How to Protect Your Sperm From Heat: The Simple GuideHeat is bad for sperm, but what do you actually do about it? The complete, simple version: find your heat sources, then reduce them ...Read the guide →
GUIDE 10Summer Heat and Your Sperm: The Seasonal Dip Nobody MentionsSperm quality tends to dip in summer. If you are trying to conceive, the season is quietly part of the equation. Here is the pattern...Read the guide →
GUIDE 11Hot Tubs, Hot Baths and Male FertilityHot water is one of the most effective ways to overheat the testicles. Here is the honest picture for fertility, and how to keep the...Read the guide →
GUIDE 12Does Tight Underwear Affect Sperm? Boxers vs BriefsThe oldest fertility advice going: wear loose boxers. Is there anything to it? Yes, a little, and it is the easiest change on the li...Read the guide →
GUIDE 06Does Polyester Underwear Lower Sperm Count?
THE SHORT ANSWER
There is not strong clinical evidence that wearing everyday polyester underwear lowers sperm count. Polyester is a...Read the guide →
GUIDE 07Spermmaxxing: What Actually Works, and What Is Just DangerousHeat, cooling and underwear: what spermmaxxing research supports, where the evidence is limited, and the questions worth asking.Read the guide →
GUIDE 08The 74-Day Rule: How Long Sperm Takes to Regenerate — and What You Can Change TonightSperm regenerate on a roughly 74-day cycle. Here is what the published research says about heat, fabric and timing — and the two inp...Read the guide →
GUIDE 09How to Protect Your Sperm From Heat: The Simple GuideHeat is bad for sperm, but what do you actually do about it? The complete, simple version: find your heat sources, then reduce them ...Read the guide →
GUIDE 10Summer Heat and Your Sperm: The Seasonal Dip Nobody MentionsSperm quality tends to dip in summer. If you are trying to conceive, the season is quietly part of the equation. Here is the pattern...Read the guide →
GUIDE 11Hot Tubs, Hot Baths and Male FertilityHot water is one of the most effective ways to overheat the testicles. Here is the honest picture for fertility, and how to keep the...Read the guide →
GUIDE 12Does Tight Underwear Affect Sperm? Boxers vs BriefsThe oldest fertility advice going: wear loose boxers. Is there anything to it? Yes, a little, and it is the easiest change on the li...Read the guide →
