Burke Karen E
Department of Dermatology, Mount Sinai Medical Center, New York, USA.
Dermatol Ther. 2007 Sep-Oct;20(5):314-21. doi: 10.1111/j.1529-8019.2007.00145.x.
Although many cosmeceutical formulations contain vitamin C and/or vitamin E, very few are actually effective in topical application. First because there is only a low concentration, second because the stability is compromised as soon as the product is opened and exposed to air and light, and third because the form of the molecule (an ester or a mixture of isomers) is not absorbed or metabolized effectively by the skin. However, when a stable formulation delivers a high concentration of the nonesterified, optimal isomer of the antioxidant, vitamins C and E do indeed inhibit the acute ultraviolet (UV) damage of erythema, sunburn, and tanning as well as chronic UV photoaging and skin cancer. Both are highly effective depigmenting agents. Topical vitamin C also increases collagen synthesis in both young and old fibroblasts. Because vitamin C regenerates oxidized vitamin E, the combination in a cosmeceutical formulation is synergistic - particularly in UV protection.
尽管许多药妆配方中都含有维生素C和/或维生素E，但实际上很少有在局部应用时有效的。其一，因为其浓度较低；其二，因为产品一旦开封并暴露于空气和光线下，其稳定性就会受到影响；其三，因为分子形式（酯或异构体混合物）无法被皮肤有效吸收或代谢。然而，当一种稳定的配方提供高浓度的非酯化、最佳异构体的抗氧化剂时，维生素C和E确实能抑制急性紫外线（UV）造成的红斑、晒伤和晒黑损伤，以及慢性紫外线光老化和皮肤癌。二者都是高效的色素沉着抑制剂。局部使用维生素C还能增加年轻和老年成纤维细胞中的胶原蛋白合成。由于维生素C能使氧化的维生素E再生，所以在药妆配方中二者结合具有协同作用——尤其是在紫外线防护方面。
