Resveratrol is a natural polyphenolic compound found in various plants, including grapes, berries, and peanuts. Resveratrol impurities refer to the other compounds that may be present alongside resveratrol in these plants or in synthesized resveratrol products. These impurities may affect the purity and potency of resveratrol and need to be carefully monitored and controlled in the manufacturing process to ensure the safety and efficacy of the final product.