Flavonol proanthocyanidin extract from grape seeds, providing antioxidant activity against peroxyl free radicals.* Allergy Research Group® grape seed extract raw material contains not less than 95% total polyphenols, including 83% oligomeric proanthocyanidins (according to the industry standard, determined as the difference between total polyphenols and monomeric polyphenols). They are water soluble, and are generally well tolerated.