Nitric Oxide Ultra (capsules) offers a blend of CranLoad and citrulline to support healthy blood flow by targeting nitric oxide production and flow mediated dilation. The formula centers around CranLoad , a fruit blend developed as part of an extensive research program with the Institute of Nutrition and Functional Foods (INAF) and Université Laval in Quebec, Canada. CranLoad delivers a unique cranberry and grape seed blend that has been the subject of several trials on arterial function and athletic performance. Cranberries and grapes are particularly generous sources of proanthocyanidins and polyphenols. In addition to being antioxidants, these compounds support vascular health and endothelial function through a variety of mechanisms. Research indicates that CranLoad provides significant support for healthy flow-mediated dilation (FMD). FMD reflects blood vessel dilation mediated by nitric oxide synthase (NOS), an enzyme that generates the endogenous vasodilator, nitric oxide. The increase was similar to published values for high doses of l-arginine. Citrulline is included to support nitric oxide production by NOS in the blood vessel endothelium and other tissues. Research indicates that citrulline increases plasma arginine in a dose dependent manner and to a greater degree than arginine.