AHA/BHA/PHA

Best for: uneven texture, congested pores, dull or oily skin that needs gentle, regular exfoliation.

Three families of chemical exfoliants, each with a different job:

AHA (glycolic, lactic acid) — surface exfoliation for tone and smoothness.
BHA (salicylic acid) — oil-soluble, cleans inside pores for blackheads and breakouts.
PHA (gluconolactone) — larger molecule, gentler for sensitive skin.