Ew but true. Bacteria naturally live on your skin, and they feed on the salts and proteins in your sweat. The byproducts of their digestion smell bad—that’s what we know as B.O. Traditional antipersperants prevent B.O. by inhibiting the production of sweat. New alternative deodorants work by inhibiting the bacteria’s growth in the first place, either using a physical barrier or by increasing the pH level on your skin.

READ MORE: A Convenient Alternative to Deodorant Sticks