The capacity of several compounds to disperse melanin pigment and/or accelerate epidermal turnover can result in skin lightening. Chemical substances used as exfoliates, such AHAs, free fatty acids, and retinoic acid, stimulate cell renewal facilitating the removal of melanized keratinocyte, leading to melanin granules loss (53). Topical application has been shown to reduce the visibility of age spots without reducing their size or number (54), and can be useful in the treatment of melasma (55).
Unsaturated fatty acid, such as oleic acid, linoleicacid, or alpha-linolenic acid, suppress pigmentation, in vitro, whereas saturated fatty acids, such as palmitic acid, increase the rate of melanogenesis (56).