Energy Source 4 1 is a state of the art sports fuel for use during exercise & to help muscles recover after exercise. Energy Source 4 1 combines a special mix of 4 parts complex carbohydrate to 1 part whey protein. Research shows that this ratio drives more energy into working muscles providing athletes with a 24 29 increase in endurance over carbohydrate only drinks & a 57 increase in endurance over water.