- Soy protein contains all essential amino acids, however it contains estrogen-like compounds called isoflavones that may exhibit estrogenic activity in people, causing some bodybuilders to avoid it.
- Egg white protein is a lactose- and dairy-free protein.
Glutamine is the most abundant amino acid found in human muscle and is supplemented because supplement manufacturers claim the body's natural glutamine levels are depleted during anaerobic exercise. It is argued that supplementation by bodybuilders may be required as deficiency may lead to a weakened immune system and wasting of muscle tissue. It is sold as a micronized, instantly soluble powder.
Amino acids are the building blocks of protein; the body breaks consumed protein into amino acids in the stomach and intestines. There are three branched chain amino acids (BCAAs): leucine, isoleucine, and valine. Each has numerous benefits on various biological processes in the body. Unlike other amino acids, BCAAs are metabolised in the muscle. BCAAs have an anabolic/anti-catabolic effect on the muscle.