Best Resveratrol features ResVinol-25™, a proprietary extract providing concentrated levels of polyphenols and trans-resveratrol from red wine matrix and the root of the Japanese knotweed (Polygonum cuspidatum) plant. Resveratrol exists in both trans- and cis-forms. However, published research suggests that only the trans- form has considerable biological activity. ResVinol-25™ is a high-quality extract subjected to rigorous ProfileProven™ analytical and quality assurance procedures designed to ensure potency and purity of the extract from batch to batch. The product is extensively tested for heavy metals, bacterial and fungal contaminants, and pesticides to verify purity and compliance with acceptable standards.