Six years ago, Dr. Paul Savage was a pudgy mess. A 38-year-old emergency-room director in Waukegan, Ill., he weighed 267 pounds, suffered from high blood pressure and shortness of breath and had sallow skin that drooped in wattles around his chin. Today, at 44, he's a new, unrecognizable man. Almost 100 pounds lighter, he boasts 12 percent body fat, a superhero jaw line and skin tone that seems almost incandescent. Savage says he owes much of his transformation to the self-administration of human growth hormone (H.G.H.). ''I worked with a personal trainer and a nutritionist first,'' he says. ''I actually gained three pounds. Then I started growth hormone, and the weight dropped away.''
Like a freshly hatched evangelist, Savage quit emergency-room medicine and in 2004 co-established a clinic in Chicago dedicated to hormone therapy, with an emphasis on H.G.H. His franchise, which operates under the name BodyLogicMD, serves about 1,500 people nationwide, many of whom pay upward of $15,000 for a yearly cycle of growth-hormone injections. The patient count rises by almost 100 each month.
According to a 2005 article in The Journal of the American Medical Association, human growth hormone is being prescribed to tens of thousands of people each year at anti-aging or ''age management'' facilities like Savage's. Those who take H.G.H. -- including many doctors -- say it can restore sagging physiques, flagging endurance and wilting libidos as well as cure depression and sharpen mental acuity. ''I can't believe everybody isn't taking this,'' says Dr. Darren Clair, 53, the founder of Vibrance Health Services, an age-management clinic in Beverly Hills, Calif., and himself a dedicated H.G.H. user. No one has yet claimed that H.G.H. reduces foot odor and freshens breath, though that could be coming.
Growth hormone has also become popular with athletes who believe it builds muscle and improves speed. ''It's definitely the drug du jour,'' says Chuck Kimmel, the president of the National Athletic Trainers' Association. The catch is that it's illegal. The Food and Drug Administration has banned H.G.H. for all but a few specific medical conditions (see ''The Outlaw Drug,'' next page), and it has been banned by most professional sports leagues in the United States and by the International Olympic Committee. In June, the house of Jason Grimsley, a pitcher for the Arizona Diamondbacks, was searched on the suspicion that he received H.G.H. In Europe, bags of growth hormone were reportedly seized as evidence in a recent Tour de France doping scandal. And in July, James Shortt, a physician in South Carolina, was sentenced in federal court for his role in providing growth hormone and steroids to, among other patients, several players on the Carolina Panthers football team. As he told the former Panthers tight end Wesley Walls in a tape-recorded consultation, ''Everybody is using it.''
Aside from the nettlesome illegality of H.G.H., there's another concern: not much research has been conducted on the effects of the drug on healthy people, though there are indications that H.G.H. can do some serious physical damage. Still, it's tempting: the possibility of a firmer, faster, younger body. H.G.H. does seem to deliver on its promise, and for many people, that makes it more than worth the risk.
Most of us produce plenty of growth hormone when we're young. Our pituitary glands steadily pump it out, helping our bones to extend, our muscles to bulk and our skin collagen to stretch.
As with most hormones (notably testosterone and estrogen), the production of H.G.H. drops with age. ''There's approximately a 1 to 2 percent reduction a year'' after puberty, Savage claims, adding that over time, that results in ''decreasing muscle mass and increasing fat mass, especially around the midsection; thinning of the skin; weaker, less-dense bones.''
An unsightly affront, yes, but for athletes it could also mean a drop in performance. ''Growth hormone is the engine of bodily repair,'' Clair says. ''It tells muscles and bones to rebuild themselves.'' With less of it, even minor injuries can linger. A strained muscle that might have bothered you for a day or two when you were 20 can twinge for weeks when you're 35, in part because of decreased levels of H.G.H.
There's some scientific evidence that increasing your H.G.H. may indeed speed healing. In a recent study conducted at several hospitals worldwide, patients who had broken tibiae were given daily injections of H.G.H. for up to 16 weeks. (Growth hormone is degraded by stomach acid and can't be taken in pill form.) The injections brought their levels up above those considered normal for teenagers. The treatment, the researchers found, ''accelerated healing significantly.''
Few clinical studies have looked at what happens when healthy people supplement their H.G.H. levels for sustained periods of time, but advocates point to one report in particular, from The New England Journal of Medicine in 1990. Twelve men in their 60's and older were given injections of H.G.H. for six months. They received high doses, about double those given to adult patients with growth-hormone deficiency. At the end of the study, the men had a 14 percent decrease in body fat, an 8.8 percent increase in lean body mass and a 1.6 percent increase in the bone density of their spine, equivalent in magnitude, the authors concluded, ''to the change incurred during 10 to 20 years of aging.''
This study almost single-handedly started the H.G.H. industry. But the doctors who recommend growth hormone tend to ignore an editorial that ran in the same issue of The Journal and that warned about the use of H.G.H. by healthy people. The editorial noted that H.G.H. can alter the body's ability to metabolize carbohydrates, leading to blood-sugar imbalances and, in some cases, diabetes. It can cause bones to thicken, contributing to joint pain and severe arthritis. Amounts of H.G.H. even slightly beyond the normal range can result in high blood pressure, edema and, in the worst cases, congestive heart failure. In a later editorial, which cited a more recent study, The Journal added that healthy people who took extra doses of H.G.H. gained muscle mass, but they didn't get stronger. Only those who lifted weights did.
Doctors worry about another possible danger of H.G.H. ''Growth hormone is a trigger for unbridled cell growth,'' says Dr. Thomas Perls, an associate professor at Boston University School of Medicine and the director of the ongoing New England Centenarian Study, which looks at the genetics and lifestyle habits of people who live to be 100. ''That's its role in the body. That is also the mechanism behind cancer.'' Several studies have linked high production levels of growth hormone to the development of prostate tumors and invasive breast cancer.
''My mother wanted to be healthy,'' says Erick Schenkhuizen, a financial planner in San Diego, whose mother, Hanneke Hops, an avid tennis player and runner, began taking almost daily injections of H.G.H. in 2003, at 56. Her prescribed dose, like those for most patients at anti-aging clinics, was designed to raise the hormone level back to where it had been years earlier. She lost 16 pounds in two months and raved in The San Francisco Chronicle that the drug ''makes me feel good.'' Seven weeks later, she was diagnosed with multiple inoperable tumors in her liver, pancreas and ovaries, and seven weeks after that, she was dead. Was there a connection between the hormone injections and the cancer? ''I don't suppose we'll ever know,'' Schenkhuizen says. ''But my mother questioned it. I question it.''
As does Perls. ''It may be that the decline in growth hormone with age is a protective measure by the body to reduce the risk of cancer,'' he says. ''My fear is that using growth hormone could be like throwing gasoline on the fire of cell growth. It could cause cancers to grow and metastasize rapidly and be untreatable by the time they're detected.''
At the heart of the H.G.H. debate is a philosophical question about what it means to grow older. ''Is aging a disease?'' asks Dr. Susan G. Nayfield, the chief of the geriatrics branch at the National Institute on Aging. Should you fight it by dosing yourself with hormones until your blood runs with levels similar to those you had in college? ''People tried that with hormone-replacement therapy'' for menopausal women, Nayfield says. ''We know how that turned out.'' (The Women's Health Initiative's long-range national study of the effects of supplementing declining estrogen and progesterone levels in menopausal women was halted in 2002. Against all expectations, the extra doses of hormones significantly increased the risks of breast cancer, heart disease, stroke and mental impairment.)
''Maybe the body knows what it's doing when it tells you to slow down a little over time,'' Nayfield concludes. ''Maybe we should listen.''
But that advice can gall those of us who once were faster, once were slimmer, once were superbly fit. ''Athletes hate to think they're a step slower than they used to be or that they're one step slower than that guy over there,'' says Chuck Kimmel of the trainers' association. ''They want a magic bullet.''
For the moment, those who use H.G.H. are convinced they've found it. ''I subscribe to the theory that hormone balance gives a person the optimal rate of health,'' Paul Savage says. ''It has certainly been true for me.''
THE OUTLAW DRUG: DESPITE ITS POPULARITY, MOST H.G.H. USE IS ILLEGAL
UNLIKE MOST DRUGS, H.G.H. can be prescribed only to treat illnesses for which it has been specifically approved by the Food and Drug Administration: primarily growth-hormone deficiency in children and adults and wasting syndrome in people who have AIDS. By law, an adult is hormone-deficient only if the diagnosis has been confirmed by laboratory tests in which the pituitary gland is stimulated and H.G.H. production measured. The hormone cannot be prescribed to improve athletic performance or to stave off aging. And it can't be used without a doctor's supervision, so virtually all online sales of the hormone are illegal.
In the past few years, the F.D.A. has accelerated its campaign against the use of H.G.H. for unapproved purposes, sending letters of warning to clinics and companies that promote the drug as an anti-aging treatment. But no one expects the crackdown to have much effect. ''There are too many clinics and too little manpower,'' says Dr. Thomas Perls, an associate professor at Boston University School of Medicine. At many anti-aging clinics, doctors claim that patients have clinical hormone deficiency, which afflicts about one in 10,000 adults. ''But the doctors don't do the stimulation test,'' Perls says. So the diagnosis isn't legally valid.
If you've been beguiled by reports about the wonders of H.G.H., ''see an endocrinologist,'' Perls urges, and get a full hormonal work-up. What you do after that is between you and your lawyer.