Premium Supplements Cardiovascular Support Dietary Supplement This L-Arginine in this product is a sustained-release nutrient that supports healthy cardiovascular function. L-Arginine promotes vascular relaxation for optimal blood flow and overall cardiovascular support. Maintaining the natural, healthy function of your vascular endothelium (blood vessel lining) is dependent upon an adequate supply of L-arginine being available to these cells. With an adequate supply of L-arginine, blood vessel linings create nitric oxide (NO) primarily resulting in vessel relaxation. This in turn helps lead to the promotion of optimal blood flow throughout your body. Mercola has been providing quality products since 2001.