Human growth hormone is a natural substance that fuels growth during childhood and helps maintain tissues and organs in adulthood. It is also sold as a prescription drug for short children whose bodies don't produce enough of it on their own. It also is used to treat the wasting associated with AIDS.
Until 1985, it was derived from the pituitary glands of human cadavers. A finite supply meant the drug was expensive and often hard to come by.
Today, with five companies offering synthetic versions, officials say there is more of the drug on the market than ever. In recent years, the drug has been embraced as an anti-aging elixir, although there is no clear evidence that it works for that, or for athletic enhancement.
By one estimate, about 30% of prescriptions are for unapproved uses, although such prescribing is prohibited by federal law, according to S. Jay Olshansky, a University of Illinois researcher who has studied the drug.
The side effects are well documented. They include acromegaly -- an overgrowth of bone resulting in brow and jaw protrusion -- carpal tunnel syndrome and knee problems. The drug also can fuel cancer cells' growth.
Major League Baseball banned human growth hormone in 2005, but players are not tested for it.
That's because less than 0.2% of human growth hormone circulating in the body shows up in urine, so a urine test is implausible, Wadler said. Two types of blood tests are under development, but the union that represents baseball players has strenuously objected to the use of blood tests.
"If that's the case, you give them a free pass," Wadler said.
Human growth hormone has another key advantage -- it appears to boost the efficacy of steroids. Athletes taking synthetic versions of the hormone find they can benefit from low-dose anabolic steroids applied in gels and creams that aren't powerful enough to register in drug-screening tests, Wadler said.
Catlin said he didn't think steroids would fall from favor because they are so effective as performance enhancers, and catching cheaters is complicated.
"A lot of gaming goes on to beat the system," he said.
Even if tests become more sensitive, scientists can concoct new steroid formulations that produce different chemical signatures that testers won't know to look for, said Michael Bahrke, a sports psychologist who specializes in the area of performance-enhancing substances.
"It's a little bit like terrorism," he said. "There's always going to be a certain amount there, and maybe the best we can do is try to keep it at a low level. I don't think we're ever going to get rid of it."
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karen.kaplan@latimes.com
denise.gellene@latimes.com
Times staff writers Julie Cart and Bill Shaikin contributed to this report.
