Pitching growth hormone as a fountain of youth

"Reverse age -- naturally."

"Restore your looks, health, energy and physical abilities."

Claims on "anti-aging" websites promise that human growth hormone will give aging adults better memory, better skin tone, better waistlines, a better sex drive. Not surprisingly, the benefits of the hormone -- whose U.S. sales exceeded $700 million last year -- are much more limited.

Its downsides are also greater than the ads let on, including, for men, an increased risk of diabetes. True, growth hormone can boost muscle and reduce body fat, but research shows that though you may look more buff, you may not actually be stronger.

Moreover, the hormone is effective only as a shot -- not as the commonly sold pills or sprays that can run from $500 to $1,000 a month. (It's also illegal to sell growth hormone, unless it's for very limited 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.

In healthy children and young adults, growth hormone is made in the front part of the pituitary gland, just underneath the brain. Some extremely short children are deficient in growth hormone; for them, the hormone is safe and effective.

In adults, production of growth hormone naturally begins to decline at about age 30. But the only adults for whom doctors can legally prescribe it are those with pathological -- not moderate and age-related -- deficiencies, or for AIDS patients with wasting syndrome.

The growth hormone craze has been building since 1990, when a six-month study in 12 men older than 60 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. The study, published in the New England Journal of Medicine, did not assess actual strength or exercise endurance, but it was a huckster's dream.

By February 2003, the growth hormone boom had become so "unnerving," as the New England Journal editor Dr. Jeffrey Drazen put it in an editorial, that the journal posted a disclaimer on its website 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 the safety and efficacy of the hormone. For one thing, many websites sell the hormone in ineffective forms -- pills and sprays that supposedly contain growth hormone or stimulate the body to make it.