Resveratrol, a polyphenol found in Japanese Knotweed and the skin of red grapes, is a very effective anti-oxidant with 95% efficiency in preventing lipid peroxidation as compared with 37% for Vitamin C or 65% for Vitamin E. Resveratrol is effective against photoaging due to its anti-oxidant properties, and is recommended for use in pre- or post-sun exposure products. Resveratrol can pass through the stratum corneum to be found in the dermis and epidermis. It has been shown to preserve dermal collagen, and may be effective in enhancing glycosaminoglycans, which enhance tissue hydration. It has been shown to stimulate skin’s cellular renewal, and help increase skin’s thickness. And it has been shown to inhibit tyrosinase, which indicates its use for reducing hyperpigmentation.
Resveratrol has shown anti-fungal and anti-bacterial activity, and has been included in products intended for diabetic wound care. It demonstrates sustained bacterial activity against P. acnes, the bacteria that causes acne. Whereas benzoyl peroxide showed a short term bacterial response, resveratrol showed a significant inhibition of growth over time. It also inhibits keratinocyte proliferation, which contributes to the formation of acne lesions.