Whey protein, soybean protein and casein are all sources of protein, but there are some differences between them. Whey protein is extracted from milk, which contains high digestibility and amino acid content. Whey protein is the most popular type of protein powder for people who want to be absorbed by protein in time. Soybean protein is a protein extracted and separated from beans. Because it is a plant protein, health and safety will be more reassuring, and it is also the main way for all kinds of people to supplement protein. Casein is a phosphorus-containing calcium-binding protein separated from milk and goat's milk. Casein belongs to macromolecular protein, which is extremely difficult to be digested and decomposed. Therefore, it is also called sustained-release protein, and can also be used to supply protein to the body for a long time.