Alpha hydroxy acids (AHA) work mainly as an exfoliant to slough off dead skin cells , making room for regrowth of new skin. AHA may improve the appearance of wrinkles, roughness, and mottled pigmentation of photodamaged skin after months of daily application. 

Beta hydroxy acids (BHA) such as salicylic acid are topical exfoliants that can reverse the appearance of the effects of photoaging such as fine wrinkles and discolored skin. BHA works effectively to prevent future acne and clears up blocked pores.