Human growth hormone (HGH) stimulates the growth of bones and affects the metabolism of carbohydrate, protein, and fat. It is secreted by the pituitary gland, which is located in the brain. Whereas HGH is produced in the body, genetic engineering has resulted in the development of recombinant human growth hormone (rHGH), which is used to treat stunted growth in children. Bovine somatotropin (BST) is a naturally occurring protein hormone in cows that increases milk production when administered as a supplement. BST is not biologically active in humans and is broken down into inactive amino acids and peptides when consumed. Therefore, milk from cows treated with BST is believed to be as safe and nutritious as milk from untreated cows.
Supplemental HGH is used by athletes, particularly body builders and power lifters, to increase muscle mass and decrease body fat. Individuals who are HGH-deficient and take supplemental HGH will see an increase in muscle mass and decreased body fat, whereas those with normal HGH levels will see an increase in lean body mass from an increase in the size of heart,
Rosenbloom, Christine, ed. (2000). Sports Nutrition: A Guide for the Professional Working with Active People, 3rd edition. Chicago: American Dietetic Association.
Williams, M. (1998). The Ergogenics Edge. Champaign, IL: Human Kinetics.