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.
For years, cheaper supplies from unauthorized foreign factories, particularly in China, fed the market via direct and Internet sales that sidestepped the medical establishment.
Though such shipments were banned under other law, the imports initially attracted little attention because they were usually labeled as raw pharmaceutical ingredients, which compounding pharmacies are allowed to bring into the country.
That flow began to be curtailed in 2006, when U.S. drug authorities stepped up efforts to block shipments at the border.
A handful of pharmacies across the country were hit with criminal charges over their handling of HGH. Federal prosecutors charged China's biggest HGH maker, GeneScience Pharmaceutical, with illegally distributing its Jintropin brand in the U.S. The company's CEO pleaded guilty in 2010.
With illicit supplies crimped, many pharmacies stopped selling unauthorized HGH. But tens of thousands of adult abusers began buying pricey U.S.-approved HGH that remained available in abundant supply, the AP found in its analysis of sales data.
Thus, pushed by a powerful demand, sales of U.S.-approved brands have swelled far beyond expected levels for a drug approved in just a handful of rare conditions.
Dr. Robert Marcus, a retired hormone specialist who left HGH manufacturer Eli Lilly and Co. in 2008, said that company was bent on stopping foreign counterfeits, not on cutting off abusers. "That's where their major level of frustration was — pharmaceutical fraud — rather than focusing on people who were using growth hormone illegitimately," he said.
Dr. Jim Meehan, of Tulsa, Okla., who has used HGH to treat aging problems and sports injuries, said the federal clampdown "never seemed to affect my patients and their ability to get Omnitrope, Tev-Tropin" and other government-approved brands.