5. Use Bleaches And Exfoliants
"When it comes to darkened under arm skin, like all hyperpigmentation, this needs exfoliants and bleaches," says Dr. Neal Schultz, board certified MD, NYC dermatologist, founder of DermTv.com and creator of BeautyRx by Dr. Schultz. “However, because the under arm skin is more sensitive, you need lower strength acids and bleaches (as noted above for age spots)."