Whey protein is one of the most popular types of protein powder on the market. But what is whey protein, and what are its benefits? When true protein is a type of protein that is derived from milk. It is a complete protein, which means that it contains all of the essential amino acids your body needs. Whey protein is also low in lactose, making it a good option for those who are lactose intolerant. There are many benefits to taking whey protein. It can help build muscle, lose weight, and increase strength.