Nutraceuticals

Some topical antioxidants (especially vitamins C and E, ubiquinone [coenzyme Q], and genestein) are effective in preventing ultraviolet damage to the skin (including sunburn, tanning, photoaging, and skin cancer) and can reverse the appearance of wrinkles and the pigmentation of solar lentigos. The formulation of each specific topical antioxidant is of utmost importance to assure stability in a commercial product with absorption by the skin and maintenance of activity after absorption. Both α-lipoic acid and its metabolite dihydrolipoic acid might protect the skin from oxidative stress, with similarities and differences in their activities and mechanisms of action. Animal and human studies have produced varied results, some demonstrating potential for adverse reactions. Topical as well as oral ubiquinone (coenzyme Q10) act as both an antioxidant and a bioenergetic generator to retard intrinsic and extrinsic aging of the skin and to accelerate healing. Genestien, an isoflavone isolated from soy, inhibits carcinogenesis by inhibitng tyrosine protein kinaces (TPKs). As a potent antioxidant, topical genestein protects against photoaging, and inhibits UVB-induced skin cancer. As a phytoestrogen, genistein enhances collagen synthesis in both intrinsic aging and photoaging and promotes healing.