Most gynecologists recommend cotton, since it’s breathable, hypoallergenic, and less likely to trap heat or moisture than synthetics. “Cotton underwear helps keep moisture away from the body and eliminates targeted heat,” says Monica Grover, MD, ob-gyn and chief medical officer at medi-spa Vspot. Too much warmth or dampness can throw off vaginal pH and lead to irritation or infection.
Synthetic fabrics aren’t completely off-limits, but experts suggest wearing cotton especially for workouts, when sweat can build up. For people with chronic irritation or vulvar conditions, sticking with underwear that’s 100% cotton—or at least 90% cotton—is often the most comfortable choice.
