LACTIC ACID is perhaps better known as AHA - a general name for fruit acids, an effective and very popular component in many skin products. Fruit acid acts primarily by breaking small bridges (demosomer) that binds skin cells together, and makes the skin's outer dead cells better peel off and give place to new. In addition, lactic acid stimulates the skin's vitality more generally, by "fanning the earth", leaving more room for the invigorating intracellular matrix structure.