Human growth hormone has become the fix of the moment, from athletes who hope it will boost their recovery, to older people who have flocked to clinics that promote the drug as a fountain of youth.
But there is little or no evidence that human growth hormone provides any of those benefits to healthy individuals, researchers and hormone specialists say, while overuse carries serious risks, including diabetes and heart abnormalities.
"People should think twice about using it," says Anne Nelson, the scientific project manager for growth hormone studies at the Garvan Institute of Medical Research in Sydney.
"It seems silly to be spending a lot of money on growth hormone if it's not doing anything and there's long-term risks to health. And it's against the spirit of sports."
Nonetheless, sales of human growth hormone, or HGH, worldwide total more than $US1 billion ($1.19 billion), and hundreds of thousands of prescriptions are filled in the United States, far more than the probable number of people with confirmed hormone diseases for which the drug can legally be prescribed.
The drug can legitimately be prescribed only for children with growth abnormalities, adults with documented deficiencies of the hormone, and people with wasting from AIDS or other serious conditions.
But synthetic growth hormone and substances to boost natural growth hormone are widely marketed on the internet with claims of bodybuilding, rejuvenation and even increased sex drive. A Google search for growth hormone sales yields more than 2 million pages, including many advertisements for pills or sprays, even though the only effective way to get HGH into the body is by injection. A month's dose can cost up to $US1000.www.theage.com.au