

Dusting powder for underarms is a dry deodorant step: starch or mineral powder that soaks sweat and cuts skin-on-skin rub. It is not a clinical antiperspirant and will not block sweat glands the way an aluminum stick can. US listings now lean talc-free, with arrowroot, cornstarch, or tapioca, sometimes zinc. Scent is optional. Apply on fully dry skin after a shower; powder on damp pits turns to paste. Skip bakery-style glitter powders with no absorbent claim.
If you also chafe on the inner arm, a puff or shaker that meters a thin layer beats dumping half the tin in a sleeve.