oPC 3 contains a combination of oligomeric proanthocyanidins (OPC's) from sources that include grape seed, red wine and pine bark† extracts. The grape seed extract is the superior source of OPCs, containing 92% of active ingredients over pine bark's 84% of active OPC ingredients.The red wine extract contains flavonoids called leucocyanidins from the skin of red grapes. Leucocyanidins are bioflavonoids with powerful antioxidant properties crucial to their role in supporting the circulatory system OPC 3 also contains bilberry and citrus extracts, which are known to have effects of vision and histamine release, respectively.this powerful formula will be delivered to your system the way nature intended it to be - in an isotonic solution that maximizes absorption. OPC 3 has a pleasant natural grape flavor, is a vegetarian product, and mixes instantly when added to water. This product should be taken on an empty stomach for the fastest, most effective delivery of the active ingredient.oPC 3 contains a combination of oligomeric proanthocyanidins (OPC's) from sources that include grape seed, red wine and pine bark† extracts. The grape seed extract is the superior source of OPCs, containing 92% of active ingredients over pine bark's 84% of active OPC ingredients.The red wine extract contains flavonoids called leucocyanidins from the skin of red grapes. Leucocyanidins are bioflavonoids with powerful antioxidant properties crucial to their role in supporting the circulatory system OPC 3 also contains bilberry and citrus extracts, which are known to have effects of vision and histamine release, respectively.this powerful formula will be delivered to your system the way nature intended it to be - in an isotonic solution that maximizes absorption. OPC 3 has a pleasant natural grape flavor, is a vegetarian product, and mixes instantly when added to water. This product should be taken on an empty stomach for the fastest, most effective delivery of the active ingredient.oPC 3 contains a combination of oligomeric proanthocyanidins (OPC's) from sources that include grape seed, red wine and pine bark† extracts. The grape seed extract is the superior source of OPCs, containing 92% of active ingredients over pine bark's 84% of active OPC ingredients.The red wine extract contains flavonoids called leucocyanidins from the skin of red grapes. Leucocyanidins are bioflavonoids with powerful antioxidant properties crucial to their role in supporting the circulatory system OPC 3 also contains bilberry and citrus extracts, which are known to have effects of vision and histamine release, respectively.