A polyphenolic antioxidant compound found in red grapes/red wine, peanuts and certain berries – as well as a few other plants (Polygonum cuspidatum – Japanese knotweed – is the primary source used for resveratrol supplements). Studies on resveratrol have linked it to a wide range of benefits: anti-aging, anti-inflammatory, anti-cancer and improvement of cardiovascular health.
Beyond its uses for general health and (possible) longevity, resveratrol is used in many bodybuilding supplements, as it’s an aromatase inhibitor and has been shown to increase sperm production and testosterone levels in rats.
It should be noted, however, that most of the research on resveratrol itself is based on cell cultures and animals. Most human research has used food sources containing mixed polyphenols, thus, it is not known what human health benefits are associated with resveratrol supplements, nor what an effective dose might be.
A related issue with resveratrol supplements is bioavailability: although resveratrol is readily absorbed, it is rapidly metabolized and excreted.