What are AHA and BHA, and what is the difference?
Short answer
AHA and BHA are chemical exfoliating acids that dissolve dead cells on the skin surface. AHA (e.g. glycolic acid) is water-soluble and works more on the surface, good for texture and dullness. BHA (salicylic acid) is oil-soluble, gets inside pores, and suits oily and acne-prone skin. Both can irritate and cause sun sensitivity.
AHA: surface and glow
AHA (alpha hydroxy acid; like glycolic, lactic acid) is water-soluble and dissolves the bonds holding dead cells on the skin's top layer. It is preferred for rough texture, dullness and superficial spots. It appeals more to dry and normal skin.
BHA: pores and oil
BHA (beta hydroxy acid; salicylic acid) is oil-soluble, so it can clear sebum and dead cells inside the pore. It is especially suitable for oily, combination and acne-prone skin and blackheads; it also has a mild anti-inflammatory effect.
Shared rule: go slow and use sunscreen
Both should start at a low percentage and a few times a week; frequency increases as skin adjusts. Stacking many acids/retinol the same night increases irritation. Since both make skin sun-sensitive, daytime sunscreen is essential.
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Start scanningFrequently asked
Should I use AHA or BHA?
AHA (glycolic) suits dry/dull skin and surface texture; BHA (salicylic) suits oily/acne-prone skin and pores.
Can AHA and BHA be used together?
Some products combine both, but using them separately and sparingly at first reduces irritation risk; once skin is used to them they can be combined.
Why is sunscreen essential?
Exfoliating acids make skin more sun-sensitive; without protection the risk of spots and irritation rises.
This page is for general information; it is not a substitute for medical/dietary advice. Personal suitability varies by skin type, allergies and health status.