A Two-Year, Double-Blind, Randomized Placebo-Controlled Trial of Oral Green Tea Polyphenols on the Long-Term Clinical and Histologic Appearance of Photoaging Skin

BACKGROUND Green tea polyphenols (GTPs) have significant antioxidant and antiinflammatory activities, and prior short-term studies suggest that these compounds may improve photoaging skin. OBJECTIVES To evaluate the long-term effects of oral GTPs on the clinical and histologic characteristics of photoaging skin. MATERIALS AND METHODS Double-blind, placebo-controlled trial of 56 women aged 25 to 75 randomized to 250mg GTPs or placebo twice daily for 2 years. A blinded dermatologist scored the appearance of photodamaged facial skin at 0, 6, 12, and 24 months. A blinded dermatopathologist scored the histologic characteristics of sun-exposed arm skin at 0 and 24 months. RESULTS Clinical assessment of facial skin revealed that the GTP group had significant improvement in overall solar damage at 6 months (p=.02) and significant improvement in erythema and telangiectasias at 12 months (p =.02). The placebo group did not have significant improvements in these parameters at 6 months or 12 months. There were no statistically significant differences in other photoaging parameters at 6, 12, or 24 months in the GTP or placebo groups. Histopathologic analysis of sunexposed arm skin showed no statistically significant difference in photoaging parameters in the GTP group or the placebo group at 24 months. CONCLUSIONS Long-term supplementation with oral GTPs was not superior to placebo in improving clinical or histologic photoaging parameters after 24 months of use.