Research Summary:
Although many cosmeceutical formulations contain vitamin C and/or vitamin E, very few are actually effective in topical application. This is due to several factors. First, the concentration of these vitamins is often too low. Second, their stability is compromised once the product is opened and exposed to air and light. Third, the form of the molecule (either an ester or a mixture of isomers) may not be effectively absorbed or metabolized by the skin.
However, when a stable formulation delivers a high concentration of the nonesterified, optimal isomer of the antioxidant, vitamins C and E can indeed inhibit the acute ultraviolet (UV) damage associated with erythema, sunburn, and tanning, as well as chronic UV photoaging and skin cancer. Both vitamins are also highly effective depigmenting agents.
Topical vitamin C has been shown to increase collagen synthesis in both young and old fibroblasts. Furthermore, because vitamin C regenerates oxidized vitamin E, the combination of these two in a cosmeceutical formulation is synergistic, especially in providing UV protection.
Keywords: topical antioxidants, UV protection, vitamin C, vitamin E.
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