Megababe Sweat Absorbing Body Powder - Body Dust | Hot Weather Essential | with Lavender & Aloe | Talc-Free, All Natural | 1.7 oz (Pack of 1)

Not underwear but this helps a ton with sweaty boobs and a damp back. Megababe Sweat Absorbing Body Powder https://www.amazon.com/dp/B0F643GRVR?ref=ppx_yo2ov_dt_b_fed_asin_title&th=1