Regular resveratrol is composed of 50% trans-resveratrol and 50% cis-resveratrol; research suggests that only the trans-form has valuable biological activity. Therefore, ProHealth's Trans-Resveratrol delivers 1000mg of pure, natural trans-resveratrol per serving. Organic co-factors and BioPerine included in this formula can improve absorption & C-max blood levels up to 1544%. ** Herbal products such as this are likely to have minor color variation from batch to batch because of the geographical and seasonal variations of the raw material.