If you’re an athlete who wants to get the best results from your workout, then MET-Rx NOS Pumped should be your number one choice for a pre-workout RTD! NOS Pumped contains Arginine, an amino acid involved in the formation of nitric oxide. During workouts, nitric oxide production can help support circulation and nutrient delivery to active cells. Our NOS Pumped Complex also contains Citrulline Malate*. NOS Pumped contains Glycerin, which may help support body hydration, and 200 mg of Caffeine to promote energy flow.