Whey protein is a mixture of proteins isolated from whey, which is the liquid material created as a by-product of cheese production. Whey protein is considered a complete protein as it contains all nine essential amino acids. The protein in cows milk is approximately 20% whey and 80% casein, while the protein in human milk is approximately 60% whey and 40% casein. The proteins in whey include α-lactalbumin, β-lactoglobulin, serum albumin, immunoglobulins, and glycomacropeptide. Whey protein concentrate (WPC) contains low levels of fat and carbohydrates, while whey protein isolate (WPI) is further processed to remove all the fat and lactose. Whey protein hydrolysate (WPH) is considered to be the “predigested” form of whey protein as it has already undergone partial hydrolysis to make it easier for the body to absorb. Whey protein is usually sold as a powder and is used as a supplement to help boost muscle protein synthesis and the growth of lean muscle mass. It is also found in a variety of food products, including baked goods, cereal bars, chocolate, and coffee creamer.