The best-known AHAs are glycolic acid (from sugar cane), lactic acid (from milk or fermentation) and mandelic acid (from bitter almonds). Glycolic acid has the smallest molecule and works fastest. Mandelic acid is larger and usually feels gentler, while lactic acid also helps the skin hold on to moisture.
AHAs work in the outermost layer of the skin, the stratum corneum. They weaken the bonds between dead cells so they shed more easily. The result is a gentle exfoliation that leaves skin smoother and clearer, and can make uneven tone, fine lines and rough texture less visible.
The right strength depends on your skin and what you want to improve. Products for home use are usually milder, while stronger peels belong in a professional treatment.
How to use: Start with two or three evenings a week and build up gradually if your skin is comfortable. Some redness, dryness or tingling at first is common. Avoid layering other strong acids or retinol on the same evening until you know how your skin reacts.
Good to know: AHAs make skin more sensitive to the sun, so wear sun protection every day, all year round. Citric acid often appears in ingredient lists, but there it is mainly used to adjust pH.
