Protein concentrates are the most common form of whey protein that is made from dairy whey to remove most of the fat, lactose, and unwanted material. Whey concentrate contains from 34 to 89% of protein and is an excellent source of branched chain BCAA amino acids. Compared to protein isolates, it contains more fat, carbohydrates, and lactose, and is slightly more difficult to digest. Protein concentrates are suitable for diet, but also for muscle mass gain.