AHA vs BHA: which exfoliating acid does your skin need?
AHAs work on the skin's surface and are best for dullness and rough texture. BHA (salicylic acid) is oil-soluble and works inside pores, so it is usually the better pick for oily skin and blackheads. Some products, like the medicube Zero Pore Pad, combine both.
AHAs: alpha hydroxy acids
Common examples are glycolic, lactic, and mandelic acid. They are water-soluble and loosen the bonds between dead cells on the surface. Glycolic acid has the smallest molecule and tends to penetrate most quickly, which can also mean more stinging. Lactic and mandelic are often described as gentler.
Good for: dullness, rough texture, uneven tone, and drier skin that still wants exfoliation.
BHA: beta hydroxy acid
In skincare, BHA almost always means salicylic acid. Because it dissolves in oil, it can work within the oily lining of pores. It is also known for calming properties.
Good for: oily skin, blackheads, clogged pores, and breakouts.
PHAs: the gentler cousin
Polyhydroxy acids such as gluconolactone have larger molecules that penetrate more slowly, so they are often suggested for sensitive skin.
Can you use AHA and BHA together?
Yes, many products combine them. The risk is cumulative irritation, especially if you also use retinoids. Start slowly and watch for the signs of over-exfoliation.
Safety basics
- AHAs can increase sun sensitivity; wear sunscreen daily.
- Patch test new acids.
- Ask a doctor about salicylic acid if you are pregnant or allergic to aspirin.
See how these acids show up in real products in our medicube vs COSRX comparison.