For most people, underarm care begins and ends with soap and deodorant. On TikTok, armpit routines are giving one of the least glamorous parts of your body the full skin care treatment. The Lowdown On Underarm RoutinesOne ingredient has become the unofficial star of armpit routines on TikTok: glycolic acid. Beyond glycolic acid, underarm routines can get surprisingly elaborate. Asked what else he recommends for underarm care, his answer was simple: nothing.