Whitening cosmetic ingredients. Origin, efficiency and risks

Depigmenting or whitening cosmetics are attracting growing interest in cosmetology. The active ingredients used are natural or synthetic chemical substances with the ability to act at different levels of melanogenesis. They are used to combat hyperpigmentation, abnormal skin colorations or to obtain a lighter skin tone. In therapeutic application, depigmenting agents can be used to treat a number of pathologies, such as different types of hypermelanosis or different forms of lentigo. However, recent studies have demonstrated the harmful effects of certain active ingredients (hydroquinone, corticoids, mercurial derivatives) on human health, with, for example, the development of skin complications or facial lesions, leading to the definitive withdrawal of certain active ingredients from the market. Against this backdrop, European cosmetics regulations prohibit or restrict the use of certain molecules that may induce undesirable side effects.

This article highlights the regulations governing depigmenting active ingredients, the main mechanisms involved in melanin synthesis, the different methods for determining whitening activity and the dangers associated with depigmentation. A second section summarizes the main active ingredients of synthetic and natural origin currently used in cosmetic formulations. Finally, the activity of natural ingredients is compared with the structure of the active molecules.

As is customary in the profession, the concentrations specified in the text are mass concentrations unless otherwise indicated.