Can polyester underwear cause infertility in men?

There is compelling evidence that polyester underwear can severely impair male fertility. A landmark study by Dr. Ahmed Shafik found that men who wore polyester underwear became azoospermic, meaning they had zero detectable sperm, within 140 days. The synthetic fabric generates electrostatic fields against the skin that interfere with normal spermatogenesis. Crucially, sperm counts recovered fully once the men switched back to natural-fiber underwear, confirming that polyester was the direct cause.

The mechanism involves electrostatic charges created by friction between polyester fibers and the skin. These charges disrupt the delicate electrochemical environment that the testes require for healthy sperm production. In addition, polyester traps heat and moisture against the body, raising scrotal temperature beyond the narrow range needed for optimal sperm development. The combination of electrostatic disruption and thermal stress makes polyester one of the most hostile fabrics for male reproductive health.

Switching to natural-fiber underwear made from organic cotton, merino wool, or hemp eliminates both the electrostatic and thermal issues. ONDU curates brands like Pact and Organic Basics that offer comfortable, breathable alternatives specifically designed to support your body rather than work against it.