Whey contains all nine of the essential amino acids, making it a complete protein, according to Medical News Today. Essential amino acids must be derived from food and cannot be produced in the body, states MedlinePlus. They include tryptophan, leucine, lysine, methionine and valine.
Whey protein is a byproduct of the cheese-making process and makes up 20 percent of the protein found in milk, explains Medical News Today. Casein, commonly recognized as the curds that become cottage cheese, makes up the remaining 80 percent. After separating the two types of protein, whey is purified and sold as a food supplement in powder form. It is commonly associated with aiding the improvement of muscle protein synthesis, increasing strength, enhancing lean tissue mass and reducing body fat in individuals who follow a resistance-training program.
There are three types of whey supplements characterized by how they are processed, notes Medical News Today. Whey protein isolate has the highest percentage of protein, typically around 90 percent, with all of the fat and lactose having been removed. Whey protein concentrate contains low levels of carbohydrates, lactose and fat, but the percentages of protein vary depending on the level of concentration. Whey protein hydrolysate is a form of whey that has been through partial hydrolysis and is commonly used in baby formula and medical supplements due to its digestibility.