A patented extract of the flavanol proanthocyanidins (PAC) prepared from grape seeds. These are the most potent of the available proanthocyanidin extracts, having a higher total content of PAC (92%).

The proanthocyanidins from grape seeds were discovered and patented by the same researcher who discovered the pine bark extract, and have been well studied analytically, biochemically, toxicologically, and clinically. PAC has very powerful antioxidant activity due to the component diphenols and related structures. The proanthocyanidin flavonoids offer an excellent option for adjunct nutritional support of the small vessel circulation. Due to their superior water solubility, they are absorbed well and are generally well tolerated.