The use of green tea extract in cosmetic formulations: not only an antioxidant active ingredient

Abstract

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.