Amino Acids, like those found in Weider Nutrition Whey Aminos, make up nearly 1/3 of the skeletal muscle in the body. Proteins as well are needed by the muscles to build bulk & maintain it long after your workouts are through. The most dominant form of protein in the Weider Nutrition Whey Aminos is a very high quality whey protein. Due to a unique manufacturing process, the protein is split optimally for easy absorption. Weider Nutrition Whey Aminos contains a massive amount of protein at nearly 75%. Keeping your body in an anabolic state where the body has enough nutrients to repair & build on itself is vital to anyone looking to put on muscle mass.