NipGuards patented design uses a medical adhesive that sticks on the base of the nipple, with a hollow cavity covered by a protective layer that shields the tip of the nipple from rubbing against the shirt. Because you do not sweat through the base of your nipple, NipGuards will not fall off due to sweat. When applied properly, NipGuards will stay on in all weather conditions for any distance, including 100-mile ultra marathons and full triathlons.