Acids are skincare ingredients used for exfoliation. There are two main group of acids in skincare: alpha hydroxy acids (AHAs) and beta hydroxy acids (BHAs). Both groups loosen the fluid that binds cells to the upper layer of skin – and once this happens, a smoonther, brighter surface is revealed. As the acid dissolves the binding between skin cells, thoudsands of them usually come off at the same time.depending on the strength of the acid, this shedding can actually be visible to the naked eye.