Glycolic acid has the smallest sized molecules of all the alpha-hydroxy acids (AHA) Because of these super tiny molecules, glycolic acid can easily penetrate the skin. This allows glycolic acid to exfoliate the skin more effectively than other AHAs.
Glycolic acid reacts with the upper layer of the epidermis, weakening the binding properties of the lipids that hold the dead skin cells together. This allows the stratum corneum to be exfoliated, exposing live skin cells.
When applied to the skin, glycolic acid works to break the bonds between the outer layer of skin cells, including dead skin cells, and the next skin cell layer. This creates a peeling effect that can make the skin appear smoother and more even.