AHA, BHA, PHA: the one-line version of each (plus who they suit)

The quick version

• AHA (often glycolic or lactic acid): water-soluble, works mainly at the surface to loosen dull, flaky buildup. Often suits rough or uneven-looking texture; glycolic can feel punchy, while lactic is often a gentler starting point.
• BHA (usually salicylic acid): oil-soluble and able to work into oily-looking pores, so it’s often chosen for a congested T-zone or blackhead-prone appearance. It can still be drying or irritating.
• PHA (such as gluconolactone): larger molecules tend to exfoliate more gradually and can be a more cautious option for easily bothered skin—but “gentler” doesn’t mean irritation-proof.

Start with one acid, once weekly at first, and follow the product directions; don’t stack it right away with retinoids or other strong exfoliants. Use moisturizer, and wear broad-spectrum sunscreen in the daytime, since exfoliation can leave skin more sun-sensitive. Patch test if you’re unsure, and pause if you get persistent stinging or redness. The best match depends on the formula and your skin’s tolerance, not just the acid family.