HGH is an acronym for human growth hormone. This anabolic hormone is normally produced by the pituitary gland in the brain, although synthetic (manufactured) HGH is now available. In 1989, the use of HGH as a performance enhancer was banned by the International Olympic Committee (IOC).

Whether naturally produced or injected, HGH stimulates the growth of muscle, bone, and cartilage. Prior to the advent of the synthetic version, HGH was usually obtained and purified from pituitary glands removed from human cadavers.

HGH is produced throughout life, but is especially important during childhood and adolescence, when its increased production results in more pronounced body growth. In adults, where body growth has virtually stopped, the hormone normally assumes an important role in metabolism.

First discovered in 1956, the therapeutic benefits of HGH in the treatment of childhood growth retardation were quickly recognized, and it began to be used only three years later.

The chief athletic lure of HGH is the increased muscle size that can result from its use. Because a bigger muscle is usually stronger, athletes in events that require power and explosive strength may be able to gain a performance advantage. Weightlifting and sprinting are two sports that have well-publicized histories of HGH misuse by some competing athletes.

Increased muscle mass can also lessen the time needed to recover from training, making an athlete capable of sustaining a more intense training regimen.

For athletes who choose to exploit illegal means of enhancing athletic performance, HGH can be an attractive choice because being a naturally produced compound, the detection of HGH is not necessarily an indication of illicit use. Moreover, the levels of HGH normally present in the body can vary by more than 100 times from person to person, depending on someone's fitness and nutritional state. Thus, benchmark normal and abnormal levels of HGH are difficult to define.

The potential athletic benefits of HGH carry risks. An excess amount of the hormone can lead to acromegaly, which is the condition of the renewed and abnormal growth of hands and facial bones in adults. Internally, growth of the heart, liver, and kidneys can cause potentially life-threatening problems such as cardiomyopathy. In the latter, the abnormally enlarged heart does not pump blood efficiently and develops an irregular beat. As well, hormonally induced rapid cell growth has been linked with the development of cancer.

SEE ALSO Anabolic steroids; Doping tests; Glucocortids; Nandrolone; Prohibited substances (competition bans).