Running a risk
Patriots safety Rodney Harrison is serving a four-game suspension after admitting he used inappropriately obtained human growth hormone, a substance banned from professional sports. He is the latest of many athletes accused of, or admitting use of, the hormone in what experts say is a useless attempt to improve their performance.
Human growth hormone has become the fix of the moment.
Patriots safety Rodney Harrison said he injected the drug to help heal his football injuries. Other professional athletes allegedly took it as part of a clandestine cocktail that they hoped would boost their recovery or power. And thousands of older people 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.
In addition, use of the drug is banned in the Olympics and professional sports. And under US law, distribution of the drug to healthy people is a felony, punishable by up to five years in prison.
"People should think twice about using it," said Anne Nelson, 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 $1 billion, and hundreds of thousands of prescriptions are filled in the United States, far more than the likely number of people with confirmed hormone diseases for which the drug can legally be prescribed.
Some estimate that thousands more get the drug illegally without prescriptions, according to a 2005 article in the Journal of the American Medical Association.
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.
A law designed to bar growth hormone abuse explicitly limits the leeway doctors usually have to prescribe a FDA-approved drug for any purpose.
But synthetic growth hormone and substances to boost natural growth hormone are widely marketed on the Internet with claims of bodybuilding, rejuvenation, and even increasing sex drive. A Google search for growth hormone sales yields more than 2 million pages, including many ads for pills or sprays, despite the fact that the only effective way to get HGH into the body is by injection. A month's dose can cost up to $1,000.
Many athletes include HGH in cocktails of drugs and supplements, choosing it in part because its use is hard to detect in tests, sports specialists said.
Testing for HGH abuse is difficult because natural levels vary greatly during the day and in response to stress and exercise.
In addition, injected hormone is short lived and does not show up much in urine.
The first blood tests to detect HGH were tried at the 2004 Athens Olympics. These tests will be more widely available by the end of the year, and a second test designed to be more sensitive is being validated, said Dr. Gary Wadler, a member of the World Anti-Doping Agency, which works to end abuse of drugs in sports.
"Growth hormone is increasingly moving to center stage in our fight against doping," Wadler said.
Harrison, who helped the Patriots win the Super Bowl in 2003 and 2004, admitted last month that he had used human growth hormone and was suspended by the National Football League for the first four games of the season. The NFL banned use of HGH in 1991.
Harrison's use was uncovered by an ongoing New York investigation into HGH mills. That investigation found he had purchased HGH on the Internet from a Florida antiaging center using a prescription from a doctor who never examined him.
Harrison said he used HGH in an attempt to heal faster from shoulder and knee injuries that kept him from playing. He apologized publicly and said his purpose "was never to gain a competitive edge."
This month, two Major League Baseball players - Rick Ankiel of the St. Louis Cardinals and Jay Gibbons of the Baltimore Orioles - were linked to HGH in the same investigation, according to media reports.
Ankiel said he received the drugs from another Florida antiaging center in 2004, under a doctor's orders after elbow surgery. He initially said the drugs included HGH, but then backtracked. A former pitcher who missed most of the 2006 season for knee surgery, Ankiel came back this season as a home-run hitting outfielder.
Gibbons allegedly received shipments of HGH from 2003 to 2005, when he was recovering from injuries, according to a report in Sports Illustrated.
Neither Ankiel nor Gibbons has been accused of any crime. Ankiel denied any wrongdoing; and Gibbons, recovering from shoulder surgery, has not addressed the accusations.
Dr. Lawrence Frohman, a spokesman for the association of doctors who treat hormone imbalances, said HGH confers no advantage in healing. However, one preliminary study, sponsored by an HGH manufacturer, found it speeded healing of certain shin fractures.
Natural growth hormone is generated by the brain's pituitary gland at levels that taper off with age. In children, HGH spurs growth, while in adults it helps to maintain a balance of fat and muscle.
A synthetic form of HGH first became available in the late 1980s. Interest in the drug took off in 1990 after a small study published in the New England Journal of Medicine suggested it could reverse some signs of aging by reducing fat, increasing lean body mass, and thickening skin in men over 60.
Subsequent research showed less dramatic effects, if any.
A review of HGH studies in older people, published in January in the Annals of Internal Medicine, found an average increase of only 4 1/2 pounds in lean body mass and a similar small decrease in fat. It found no evidence of improvements in stamina, bone density, cholesterol or longevity, but it cataloged many problematic side effects.
"There is a very limited benefit. For less money, you could get a personal trainer - and lose the weight more quickly," said the study's lead author, Dr. Hau Liu, a clinical assistant professor at Stanford University Medical Center. "You shouldn't be using growth hormone for antiaging."
One study published after Liu's review did find an increase in thigh muscle and aerobic activity in a healthy older men in the United Kingdom treated with HGH and testosterone.
Studies in young weight lifters and resistance trainers found no improvement in muscle strength, although many athletes continue to believe there's a benefit.
Research presented in June at the Endocrine Society's annual meeting found a small improvement - less than 10 percent - in sprinting capacity in young men who took HGH combined with testosterone, but no benefit for women or in those who took HGH alone.
Neither HGH alone nor with testosterone conveyed an advantage in tests of strength or power, said Anne Nelson, who oversaw the Garvan Institute research. However, most of the men said they felt stronger, even if they received a placebo.
One additional measure of the ineffectiveness of growth hormone supplements in healthy people is the lack of pharmaceutical company interest.
A Pfizer spokesman said tests showed its drug wasn't effective. Merck wouldn't comment on why it halted development.
Some sports medicine specialists caution that growth hormone may yet be found to boost function. They cite steroids, which were widely debunked as ineffective until science caught up with what body-builders had already discovered.
"Often the experimentation in the training room is ahead of the scientists," said Dr. Nicholas DiNubile, a spokesman for the American Orthopaedic Society for Sports Medicine. "But right now, for a healthy individual, there is no reason to use growth hormone."