Growth hormone is a natural hormone produced by the brain that stimulates the growth of muscle and bone. Although growth hormone has several legitimate medical uses, some athletes use it inappropriately to try to

• build muscles
• improve sports performance
• reduce body fat

However, research has not found growth hormone to be effective in building muscles or improving sports performance in healthy people. The only well-established effect of growth hormone in such people is that it decreases the amount of fat beneath the skin.

How is growth hormone used? Growth hormone only works when it is injected.

Risk of addiction: Growth hormone is not addictive.

Risks from excessive use: You cannot overdose on growth hormone from a single injection. However, continued use can cause high blood pressure, too much fat in the blood, diabetes, arthritis, increased heart size that can lead to heart failure, and abnormal enlargement of the bones of the head, hands and feet.

How is growth hormone produced? Growth hormone is manufactured by drug companies for medical use.

Can growth hormone be used legally? Growth hormone can be legally prescribed by doctors for medical conditions that require the growth of body tissues. For example, growth hormone is used to stimulate the growth of children who are abnormally short because they don't produce enough growth hormone themselves. Use of growth hormone without a prescription is illegal.

How quickly does growth hormone act? Growth hormone has few obvious short-term effects. Its ability to stimulate the growth of abnormally short children usually requires several months of daily injections before any effects are seen, and treatment may need to be continued for several years.

Drug tests for growth hormone: No reliable test is currently available for determining whether a person is taking growth hormone.

How many students use growth hormone? In some studies, 5% of 10th grade boys have reported using growth hormone to try to improve sports performance.