Topical Vitamin C and the Skin: Mechanisms of Action and Clinical Applications.

OBJECTIVE: This review article details the main mechanisms of action and clinical applications of topical vitamin C on the skin, including its antioxidative, photoprotective, antiaging, and antipigmentary effects. DESIGN: A PubMed search for the relevant articles on vitamin C and the skin was conducted using the following key words: "vitamin C," "ascorbic acid," "ascorbyl-6-palmitate,"and "magnesium ascorbyl phosphate." RESULTS: As one of the most powerful antioxidants in the skin, vitamin C has been shown to protect against photoaging, ultraviolet-induced immunosuppression, and photocarcinogenesis. It also has an antiaging effect by increasing collagen synthesis, stabilizing collagen fibers, and decreasing collagen degradation. It decreases melanin formation, thereby reducing pigmentation. Vitamin C is the primary replenisher of vitamin E and works synergistically with vitamin E in the protection against oxidative damage. CONCLUSION: Topical vitamin C has a wide range of clinical applications, from antiaging and antipigmentary to photoprotective. Currently, clinical studies on the efficacy of topical formulations of vitamin C remain limited, and the challenge lies in finding the most stable and permeable formulation in achieving the optimal results.