GU provides athletes with a shot of 100 calories in the form of a patented carbohydrate blend (70%-80% maltodextrin and 30-20% fructose) to deliver high-quality easily-digested and long-lasting energy for athletes in every sport and at all levels. GU also includes electrolytes to ensure proper hydration an antioxidant blend to stave off muscle tissue damage and an amino acid blend to delay muscle fatigue.Everything inside each packet of GU is engineered to do one simple thing: provide your body with the essential requirements it needs to keep going for miles and miles and hours and hours. It goes down easy and it goes to work fast so you don't have to slow down.