Resveratrol

Resveratrol is a natural polyphenolic compound classified as a stilbenoid. The most studied form is trans-resveratrol, a molecule with two phenyl rings joined by an ethylene bridge; it can exist in cis form under UV light. It is produced by several plants as part of a defense response and occurs in grapes and grape-derived products, including red wine, as well as in peanuts, berries, and knotweed (Polygonum cuspidatum).

Resveratrol has been investigated for antioxidant and anti-inflammatory properties in vitro and in animal models. Proposed mechanisms include activation of sirtuin 1 (SIRT1) in some studies, modulation of AMPK signaling, inhibition of NF-kB, and activation of the Nrf2 pathway, among others. However, evidence in humans is inconsistent, and many proposed effects have not been confirmed in robust clinical trials. Observed outcomes in small trials have ranged from modest improvements in insulin sensitivity and lipid profiles to no significant effect.

Orally administered resveratrol is rapidly metabolized to glucuronide and sulfate conjugates, leading to low and variable bioavailability. This has complicated interpretation of clinical results and prompted development of formulations and delivery systems to improve absorption and stability.

Resveratrol is sold as a dietary supplement in many jurisdictions; it is not approved as a treatment for disease. Dietary intake from foods is generally considered safe, but high-dose supplements may cause gastrointestinal upset or interact with certain medications; long-term safety data are limited.