While doctors say more than 90 percent of legitimate patients are children with stunted growth, 40 percent of 442 U.S. side-effect cases tied to HGH over the last year involved people age 18 or older, according to an AP analysis of FDA data. The average adult's age in those cases was 53, far beyond the prime age for sports. The oldest patients were in their 80s.
Some of these medical records even give explicit hints of use to combat aging, justifying treatment with reasons like fatigue, bone thinning and "off-label," which means treatment of an unapproved condition
Even Medicare, the government health program for older Americans, allowed 22,169 HGH prescriptions in 2010, a five-year increase of 78 percent, according to data released by the Centers for Medicare and Medicaid Services in response to an AP public records request.
"There's no question: a lot gets out," said hormone specialist Dr. Mark Molitch of Northwestern University, who helped write medical standards meant to limit HGH treatment to legitimate patients.
And those figures don't include HGH sold directly by doctors without prescriptions at scores of anti-aging medical practices and clinics around the country. Those numbers could only be tallied by drug makers, who have declined to say how many patients they supply and for what conditions.
First marketed in 1985 for children with stunted growth, HGH was soon misappropriated by adults intent on exploiting its modest muscle- and bone-building qualities. Congress limited HGH distribution to the handful of rare conditions in an extraordinary 1990 law, overriding the generally unrestricted right of doctors to prescribe medicines as they see fit.
Despite the law, illicit HGH spread around the sports world in the 1990s, making deep inroads into bodybuilding, college athletics, and professional leagues from baseball to cycling. The even larger banned market among older adults has flourished more recently.
FDA regulations ban the sale of HGH as an anti-aging drug. In fact, since 1990, prescribing it for things like weight loss and strength conditioning has been punishable by 5 to 10 years in prison.
Steve Kleppe, of Scottsdale, Ariz., a restaurant entrepreneur who has taken HGH for almost 15 years to keep feeling young, said he noticed a price jump of about 25 percent after the block on imports. He now buys HGH directly from a doctor at an annual cost of about $8,000 for himself and the same amount for his wife.
Many older patients go for HGH treatment to scores of anti-aging practices and clinics heavily concentrated in retirement states like Florida, Nevada, Arizona and California.
These sites are affiliated with hundreds of doctors who are rarely endocrinologists. Instead, many tout certification by the American Board of Anti-Aging and Regenerative Medicine, though the medical establishment does not recognize the group's bona fides.
The clinics offer personalized programs of "age management" to business executives, affluent retirees, and other patients of means, sometimes coupled with the amenities of a vacation resort. The operations insist there are few, if any, side effects from HGH. Mainstream medical authorities say otherwise.
A 2007 review of 31 medical studies showed swelling in half of HGH patients, with joint pain or diabetes in more than a fifth. A French study of about 7,000 people who took HGH as children found a 30 percent higher risk of death from causes like bone tumors and stroke, stirring a health advisory from U.S. authorities.
For proof that the drug works, marketers turn to images like the memorable one of pot-bellied septuagenarian Dr. Jeffry Life, supposedly transformed into a ripped hulk of himself by his own program available at the upscale Las Vegas-based Cenegenics Elite Health. (He declined to be interviewed.)
These promoters of HGH say there is a connection between the drop-off in growth hormone levels through adulthood and the physical decline that begins in late middle age. Replace the hormone, they say, and the aging process slows.
"It's an easy ruse. People equate hormones with youth," said Dr. Tom Perls, a leading industry critic who does aging research at Boston University. "It's a marketing dream come true."
Associated Press Writer David B. Caruso reported from New York and AP National Writer Jeff Donn reported from Plymouth, Mass. AP Writer Troy Thibodeaux provided data analysis assistance from New Orleans.
AP's interactive on the HGH investigation: http://hosted.ap.org/interactives/2012/hgh
The AP National Investigative Team can be reached at investigate(at)ap.org