The primary types of protein powders are whey, casein, pea, rice, and soy. Casein, soy, and whey are the only complete protein sources, containing all essential amino acids. There’s little to differentiate the benefits of casein, soy, and whey, though casein is the most researched. Casein is commonly recommended because the body metabolizes it slowly, meaning it increases MPS for a longer period of time. It can also improve your energy and keep you satiated throughout the day. Whey, on the other hand, absorbs quickly, thus having a shorter MPS period. Soy, pea, and rice are plant-based protein options if you are lactose intolerant, vegetarian, or vegan. However, soy is the only plant-based option containing all essential amino acids and it has a slow absorption rate.