Gu Roctane Energy drink is for the athlete who needs to fuel up for very long and very hard workouts. Roctane (named after the Hardrock 100 mile endurance run) contains an optimal ratio of complex to simple carbs, customized for rapid absorption. Roctane simultaneously provides a balanced blend of electrolytes with amino acids to reduce muscle damage and maintain concentration. Additionally, a combination of taurine and caffeine increase power output and reduce perceived fatigue, when the miles begin to add up. The best part is that all of this nutrition is delivered with a nice light taste, that's very easy on the stomach. Tropical fruit, lemon lime, or grape.