Grape Seed Extract

Grape seed extract is a concentrated source of proanthocyanidins (OPCs), which are potent antioxidants. At the highly refined extract level, it is used in some dog foods and supplements for its antioxidant properties. It is important to distinguish grape seed extract from whole grapes or raisins, which are known to be toxic to dogs — the extract is considered safe at the levels used in pet food formulation, though the research is still developing. It is used in small amounts as a natural antioxidant rather than a primary ingredient.