Human growth hormone (hGH), a protein hormone produced and secreted by the somatotropic cells of the anterior pituitary, plays a key role in somatic growth through its effects on the metabolism of proteins, carbohydrates, and lipids. The biological properties of hGH are diverse and complex, with the molecule exhibiting anabolic activity, insulin‐like and diabetogenic activities, and lactogenic activity, as well as producing effects on water and salt retention. First isolated from the pituitary gland, hGH is produced using recombinant DNA technology and has been approved for use as a human pharmaceutical in the treatment of growth failure owing to hGH deficiency and in the treatment of Turner's syndrome in Europe and Japan. In addition, hGH is being investigated for use in treating burns, various wounds, osteoporosis, cachexia, and other conditions. Human growth hormone is one of the largest selling therapeutic proteins produced by recombinant DNA technology.