Performance energy. Only 10 calories per serving. Lightly carbonated. Caffeine. Taurine. Guarana. B-vitamins. Rockstar Xdurance is designed to provide an incredible energy boost to maximize your mental and physical performance. BCAA. Branched chain amino acids. Electrolytes. (These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure or prevent any disease.) American made.