25% AHA Complex Alpha hydroxy acids (AHA) exfoliate the skin's surface breaking down the 'glue' that binds dull, dead cells for a brighter & more even appearance 6% PHA Complex Poly hydroxy acids (PHA) have larger molecular* structures compared to AHAs to provide slow, time release exfoliation to skin's surface 2% BHA - salicylic acid Beta hydroxy acids (BHA) gets deeper into the pores for deeper exfoliation from within & to clear pore congestion & regulate sebum production