Citrulline Cofactors™ provides natural ingredients to support the structure and function of the cardiovascular system. Healthy blood flow is critical to support a healthy body and that’s what a good supply of nitric oxide can do for you. Citrulline is the most convenient and effective natural nitric oxide precursor available. Cofactors are the nutrients required to assure the maximum conversion of citrulline to supply nitric oxide when and where needed. A lack of any one of the 13 cofactors can interfere with nitric oxide production.