Glycolic acid can help lighten skin. While many of the ingredients on this list work to inhibit melanin synthesis, glycolic acid works to lighten skin by removing melanin pigment faster. Glycolic acid skincare speeds up the natural turn-over of your skin cells aka the rate at which they exfoliate at. Uneven exfoliation can cause an uneven skin tone. Therefore glycolic acid can powerfully boost the results of direct acting skin lighteners like kojic acid.