Red Grape Skin extract contains a mix of substances, some of which are found in grape seeds and some in red wine. These substances include nonbioflavonoid polyphenols (derivatives of cinnamic and benzoic acid) and bioflavonoid polyphenols (quercetin, catechins, flavonols, and anthocyanidins). One of these ingredients, resveratrol, was found to have antiplatelet aggregating activity. Red Grape Skin Extract Appearance: Purple Powder Odor: characteristic Analysis by UV Proanthocyanidins > 25%