Soy Protein is the ideal choice for vegetarians, vegans and those with special dietary requirements such as lactose intolerance. Soy is a plant based protein that comes from soy beans. Like whey protein, it is considered a complete protein and contains all the essential amino acids. While whey protein is rich in the branch chained amino acids, soy protein is rich in both arginine and glutamine (Arginine helps muscle formation). Soy has a slower absorption rate than whey which means it takes the body longer to digest the protein. Therefore, soy protein in not quite as good in rebuilding muscle, but extremely helpful in forming new muscle tissue.