Muscle Builder uses PEAK ATP®, a natural compound that your body uses to enable you to lift weights, run faster and indeed power all movement. Scientifically tested to increase muscle mass and strength by 90% and 147% respectively vs a placebo, Muscle Builders offers users seeking a natural muscle builder the beauty of a supplement that works not only to increase muscle and strength but which also enhances cellular processes that enhance protein synthesis while further promoting gains in endurance.