Antioxidant compounds from grape seeds called oligomeric proanthocyanidins or OPCs help protect the circulatory system by reducing blood pressure, protecting blood vessel walls from free radical activity and dangerous oxidation, and discouraging blood clots. In one Italian clinical study, people with either pre- or mild hypertension were split into three groups. Two of the groups received either a low or high dose of grape seed extract while the third group served as a control group with simple changes to diet and exercise. At the end of the four-month trial, both grape seed extract groups saw an improvement in blood pressure, with those at the higher dosage noticing the most dramatic effects. It was so pronounced that blood pressure numbers normalized in 93 percent of those in the higher dosage group.

Other scientific studies have shown that grape seed extract helps prevent blood clots from forming without thinning the blood, lowers blood pressure, and shields blood vessels from free radical damage. Since the mighty grape seed can do so much for the circulatory system, make sure that you select a supplement that provides optimal absorbability. Grape seed OPCs must have a low molecular weight small enough to guarantee absorption. Check to ensure that your supplement is also tannin-free, as tannins are not well utilized by the body. 

For more information on grape seed extract, follow this link Published Study on French Grape Seed Extract