Enduro?works in concert with your body?s cardiovascular system to increase hydration, performance, and endurance during intense physical activity. Enduro is a non-stimulated, non-caffeinated energy booster designed with two special ingredients, L-Arginine & L-Citrulline, which help increase blood flow and oxygen to the muscles and cells of the body. The black pepper extract and bio protected blend in Enduro help maintain absorption of nutrients to the body and improve circulation and blood flow to the body.