Resveratrol

A polyphenol antioxidant found in red grape skin, berries, and Japanese knotweed. It neutralises free radicals, has anti-inflammatory properties, and in vitro data suggests it activates sirtuin pathways involved in cellular repair. Much of the excitement around resveratrol originated from oral supplementation research — the topical evidence base is thinner, though growing. Human studies confirm it reduces oxidative stress markers in skin and may enhance the effectiveness of other antioxidants (particularly vitamin C and vitamin E) in combination serums. Bioavailability challenge: it degrades rapidly in light and air, making formulation quality critical. Typically used at 0.1–1% in stable encapsulated or anhydrous formulations.