水楊酸
Salicylic acid is a beta hydroxy acid. It is antibacterial (mostly bacteriostatic, except in high concentrations when it is more frequently bactericidal) and antiinflammatory and, as a result, works well for acne. Salicylic acid also has the ability to reduce the spots and bumps associated with acne. It is becoming common for beta hydroxy acid (BHA) peels to be used instead of the stronger alpha hydroxy acid (AHA) peels due to BHA's being oil soluble. Studies show that BHA peels control sebum excretion, acne as well as remove dead skin cells to a certain extent better than AHAs due to AHAs only working on the surface of the skin.