Human growth hormone
Touted as an anti-aging agent, athletes and others are taking human growth hormone to build up muscle and lose fat.
Human growth hormone (HGH) has several legitimate medical uses. It's a treatment for dwarfism in children and Turner's syndrome, a genetic disorder affecting girls that is caused by a missing or incomplete X chromosome. On an experimental basis, it's been used successfully to treat children who have been badly burned and AIDS patients with excessive abdominal fat.
But there's a huge black market in HGH these days. Professional athletes are customers, but so are many others. The hormone has been sold as an anti-aging remedy since the early 1990s, after a study published in The New England Journal of Medicine showed that it reverses the loss of muscle and gain of body fat that accompanies old age. It's becoming popular among younger people, who often take it in combination with anabolic steroids to improve the appearance of their bodies.