Restore your looks, health, energy and physical abilities."
"What was once the secret of celebrities is now finally within the grasp of everyone."
The claims on "anti-aging" Web sites promise that human growth hormone will give aging adults everything from better memory to better skin tone, better waistlines and a better sex drive.
Not surprisingly, though, the benefits of the hormone - whose U.S. sales far exceeded $700 million last year - are much more limited. And its downsides are far greater than the ads let on, including an increased risk of diabetes, especially in men.
True, growth hormone can boost muscle and reduce body fat. But, while you may look more buff, you may not actually be stronger, research suggests. Moreover, the hormone is only effective as a shot -- not in the commonly sold pills or sprays - which can run $500 to $1,000 a month. It's also illegal to sell growth hormone, except for very strictly defined medical conditions.
People who get injections of growth hormone as an anti-aging remedy are "performing an experiment on themselves," said Boston University geriatrician Dr. Thomas Perls, who wrote a research paper in the Oct. 26 Journal of the American Medical Association condemning the drugs. "If anything, you run the risk of developing cancer prematurely, and probably aging more quickly."
Healthy children and young adults manufacture growth hormone, chiefly during sleep, in the anterior part of the pituitary gland, which lies just underneath the brain. Some extremely short children are genuinely deficient in growth hormone and for them, the hormone is safe and effective. It is legal for doctors to prescribe growth hormone for them.
The only adults for whom doctors can legally prescribe it are those with pathological - not moderate, age-related - deficiencies of growth hormone, or for AIDS patients with wasting syndrome.
In adults, production of growth hormone naturally begins to decline at about age 30.
The growth hormone craze has been building since 1990, when a six-month study of 12 older men with low levels of growth hormone showed that injections of the drug resulted in a 10-pound gain in lean body mass and a nearly 8-pound loss of fat. Though the study, published in the New England Journal of Medicine, did not assess actual strength or exercise endurance, it was a shyster's dream.
By February 2003, the growth hormone boom had become so "unnerving," as Dr. Jeffrey Drazen, editor of the New England Journal, put it in an editorial, that the Journal posted a disclaimer on its Web site alongside the 1990 study, warning readers about "potentially misleading e-mail advertisements" for the drug.
In the 15 years since the original study, medical researchers have also raised serious questions about both safety and efficacy of the hormone.
For one thing, many Web sites sell the hormone in an ineffective form - one Web site alone generated an estimated $70 million in sales of pills and sprays that supposedly contain growth hormone or stimulate the body to make it. But the sprays don't work because the growth hormone molecule is too big to get into the bloodstream. The pills don't work either, partly because they are destroyed in the stomach.
Moreover, a lot of what is sold "is not even growth hormone, it's a bunch of amino acids - it's totally useless," said Dr. Stanley Korenman, a professor of medicine and endocrinology at the David Geffen School of Medicine at UCLA. "It's pure bull."
As for safety, one of the most careful studies was a 2002 randomized, double-blind six-month experiment by Dr. Marc Blackman, a professor of medicine at the Johns Hopkins School of Medicine and chief of the endocrinology section at the National Center for Complementary and Alternative Medicine at the National Institutes of Health.
The study involved 57 healthy women and 76 healthy men aged 65 to 88, all of whom had normal age-related declines in growth hormone.
Some of the women got thrice-weekly injections of growth hormone only; some got only estrogen and Provera, commonly used postmenopausal hormones; some got both growth hormone and the post-menopausal hormones; some got placebos, or dummy versions, of both. Men got analogous treatments, with testosterone instead of the menopausal hormones.
The "good news," said Blackman, was that all the people who got growth hormone, whether alone or in combination with the other hormones, had increases in lean body mass and decreases in fat.
But that didn't turn out to mean much in real life. Despite the increase in muscle mass, the only people who got significantly stronger, as gauged by standard strength tests, were the men who got both testosterone and growth hormone. For them, the increase was significant, about 13.5 percent - a bit less than the improvement they could have achieved with a hormone-free, conventional weight-lifting program.
Similarly, the only people who showed improvement in cardiac endurance were the men who got both testosterone and growth hormone.