MET-Rx ZMA is a specialty supplement that provides you with highly bioavailable forms of Magnesium and Zinc, including Zinc L-Monomethionine (L-OptiZinc). These essential minerals each deliver a unique benefit-Zinc contributes to energy metabolism, while Magnesium is an essential component of the muscle enzyme creatine kinase, and is a vital factor in energy production and muscle contractions. Each serving of ZMA aids with energy metabolism and recovery support, and also supplies a high-potency source of Vitamin B-6, an important vitamin that acts as a cofactor to an enzyme required for aspartate metabolism.