The use of green tea extract in cosmetic formulations: not only an antioxidant active ingredient.Dermatol Ther. 2013 May-Jun; 26(3):267-71.DT
Green tea (GT) extracts contain polyphenols, known to be effective free radical scavengers, and other ingredients that could also provide benefits to the skin. This is a report on clinical studies using objective, noninvasive methods to evaluate the effects of cosmetic formulations containing GT. Experimental formulations were supplemented or not (vehicle) with 6% Camellia sinensis glycolic leaf extracts (GT). These formulations were applied to the forearm skin of 24 volunteers, and their effects were evaluated before and after 2 hours, 15 and 30 days according to the following parameters: stratum corneum water content, transepidermal water loss, skin viscoelastic-to-elastic ratio (Uv/Ue), and microrelief. The volunteers were instructed not to apply any formulation in an area of the forearm (control area). Experimental formulations (GT) increased skin moisture in the long-term study, indicating that GT has a prolonged moisturizing effect. The Uv/Ue was significantly enhanced after 30 days of topical application of the experimental formulation when compared with vehicle and control. After 15-30 days, skin microrelief was significantly improved due to a reduction in skin roughness. The results suggest that GT-containing cosmetic formulations have pronounced moisturizing effects and improve skin microrelief.