Cinnamic Acid Derivatives as Potential Melanogenesis Inhibitors for Use in Cosmetic Products.

Cinnamic acid and its derivatives are well-known cosmetic ingredients valued for their fragrance, skin-conditioning, UV-filtering, antioxidant, and antimicrobial properties. Both natural and synthetic compounds from this group are increasingly studied for their potential in skin depigmentation. Hyperpigmentation disorders such as melasma, freckles, lentigines, and post-inflammatory or hormonal pigmentation are common aesthetic concerns that remain difficult to treat effectively. Several cinnamic acid derivatives, including plant extracts containing these compounds, have shown promise as melanogenesis inhibitors. Notably, piperlongumine has already been registered as a cosmetic skin-lightening agent. Natural compounds like ferulic acid and chlorogenic acid are used in formulations for their multifunctional benefits to skin appearance and condition. Synthetic derivatives, particularly esters and amides, have also demonstrated potent anti-melanogenic activity. Interestingly, these effects may occur independently of antioxidant mechanisms. Reliable evidence supporting the efficacy of these compounds comes from advances in vitro models, such as 3D cell cultures and pigmented reconstructed human epidermis. However, clinical confirmation remains limited. To date, p-coumaric acid and extracts from bird's nest fern and pomegranate peel have been clinically evaluated. Current literature supports the continued exploration of cinnamic acid derivatives as promising candidates for cosmetic products targeting skin hyperpigmentation.