Part of the AHA (Alpha Hydroxy Acid) family, Lactic Acid is a gentle but effective entry-level exfoliator. Compared to other AHAs, Lactic Acid's molecules are larger, so it can't penetrate as deeply into the skin - which is good news for sensitive skin types as it's less likely to cause irritation. Staying on the outer layers of the skin, it un-glues dead cells to reveal brighter, more even skin tone, as well as providing additional moisture. It should be one of the first exfoliating acids you go to if you're more sensitive or cautious about exfoliation.