Chemical exfoliants dissolve the bonds between dead surface cells, revealing smoother skin. The two families work differently.
AHAs (alpha-hydroxy acids)
AHAs — glycolic, lactic, mandelic acid — are water-soluble and work on the skin's surface. They smooth texture and fade marks, and suit normal-to-dry skin and tone/texture concerns. Lactic and mandelic are gentler than glycolic.
BHA (salicylic acid)
BHA is oil-soluble, so it penetrates into pores to clear congestion. It's the better pick for oily, acne-prone, or blackhead-prone skin.
How to choose
- Dry, dull, uneven tone → AHA (start with lactic or mandelic).
- Oily, congested, breakout-prone → BHA.
Don't over-exfoliate
The most common mistake is using too much, too often. One exfoliant, a few nights a week is plenty — and don't stack acids with each other or with a retinoid in the same session (that's a fast track to a damaged barrier or over-exfoliation). The routine builder will warn you if you do. Choosing between AHAs? See glycolic vs lactic vs mandelic.