Personally, I do all my sessions without underwear (I’ve run three marathons commando). I find it more comfortable (plus, less laundry!). Still, I talked to Elizabeth Hale, a dermatologist in NYC, and Jill Maura Rabin, M.D., professor of obstetrics and gynecology at Hofstra North Shore-LIJ School of Medicine, to see what issues to consider when choosing a pair: All-cotton styles are comfy but not great at wicking away sweat.
On the irritation scale, lace is worst, while a spandex-nyloncotton combo is better. Seamless styles won’t rub. Stay dry down there to avoid skin infections, like folliculitis, caused by trapped sweat. “If you wear underwear, take it off immediately after a workout and shower. Or at least swap the sweaty pair for cotton,” says Hale. If you break out on your butt, try an over-thecounter wash with benzoyl peroxide. Staying dry and clean will also help you avoid bladder and vaginal infections, says Rabin.