COSRX The AHA BHA PHA LHA 35 Peel is ideal for experienced users who are familiar with strong exfoliating treatments. It combines AHA (Alpha Hydroxy Acid), BHA (Beta Hydroxy Acid), PHA (Polyhydroxy Acid), and LHA (Lipo Hydroxy Acid) to provide thorough exfoliation, removing dead skin cells and unclogging pores.