In studies over the past 10 years, this naturally occurring hormone prevented cancer and helped fight viruses, mostly in rodents. It restored vitality and libido to the aged and happiness to the depressed, and even slowed the tentacles of Alzheimer's disease. It made vaccines more effective in the elderly, and lowered bad (LDL) cholesterol, thus presumably protecting the heart and arteries.

Just when we began hoping that DHEA would fight flab and change the oil in the old Chevy... along came evidence that DHEA could increase insulin sensitivity, possibly reversing a primary cause of adult-onset diabetes. This blood-sugar disorder affects about 14 million Americans, according to the American Diabetes Association.

And it does seem that large doses of DHEA can help fight the bulge -- at least if you're a dog. In a study to be published in Obesity Research, University of Wisconsin-Madison scientists Ilene Kurzman and Gregory MacEwen fed a group of dogs a low-fat, high-fiber diet. Half of the dogs -- chosen at random -- also got a high dose of DHEA, but their identity was not known to the researchers during the study.

DHEA worked: while the control dogs lost 5.5 percent of excess body weight per month, the group treated with DHEA lost 10 percent, says Kurzman.

Meet the cure-all
But long before these results were due for publication, DHEA had gained a reputation as a cure-all. After Food and Drug Administration regulations were changed in 1994, it began appearing on drug store shelves as a "dietary supplement."

Yet despite years of study and a great deal of new enthusiasm, DHEA is not something that can be recommended for controlling obesity, or much else either. "I would not recommend it for weight loss," says MacEwen, a professor of veterinary medicine who's studied DHEA for almost a decade. "When you look at the rodent studies, you see that they were feeding it at about 0.1 percent of total diet."

That's a lot -- about 100 times the dose per kilogram of body weight in the pills at your drugstore. (Dietary supplement pills are formulated to restore the DHEA level to what's in the blood of a 30-year-old.)

Furthermore, as MacEwen points out, most of the obesity research has been done in mice and rats. "But a rodent is not a small human, and DHEA may have a totally different effect in people." Specifically, rodents normally have much less DHEA than humans do, so they're not necessarily a good species to test the effects of supplements.

What do we know about DHEA?
It's a natural hormone produced by the adrenal gland (that's the little critter hitchhiking on the kidney). The concentration peaks in humans about age 25 -- (need we add at the time of peak health and vitality? OK, we added it).

From that peak, blood levels decline at about 2 percent per year, raising the prospect that the hormone's disappearance could be linked to all sorts of problems of aging.

Like "not getting it" about cyber-electro-funk music? No. Like decreased immune function, heart attacks, and gaining weight.

It's not known whether DHEA is actually a hormone, or just a precursor ("raw material") for the hormones testosterone and estrogen. If it's a precursor, then taking supplements could be dangerous -- since estrogen and testosterone can both speed the development of cancers. Indeed, MacEwen says, the only side effect seen in his dog study was an increase in aggressiveness, as the dogs "tended to take on male characteristics toward other dogs." And that's a sign that DHEA is being converted into testosterone.

Can "natural" be a handicap?
And since DHEA is a natural product, it cannot be patented, depriving drug companies of the incentive to fund research.

Despite these roadblocks, researchers have tried DHEA in new ways, and gotten some intriguing results in small studies. In recent work, Owen Wolfkowitz of the University of California, San Francisco, gave DHEA to six depressed elderly people, with positive results. Stating the case in lucid terms, he wrote, "These preliminary results raise the possibility [that blood levels of DHEA and a related compound] may be pathophysiologically relevant and are amenable to pharmacologic treatment." (Press for translation.)

Other scientists have been researching whether DHEA increases the immune response to vaccinations, retards the development of Alzheimer's and Parkinson's diseases, and helps the heart by reducing atherosclerosis.

In each case, the evidence is suggestive. And yet, taken as a whole, John Nestler, a Medical College of Virginia endocrinologist who organized a 1996 conference on DHEA, remains cautious. "One can almost hear the hucksters calling out: 'Come get your DHEA, come get your Fountain of Youth. Cures all that ails you. Helps you live forever."

Despite the hype, he wrote, evidence for a real human effect was mixed -- and scanty. "DHEA was reputed to remedy almost any bodily ill, even though evidence for the beneficial effects of DHEA in humans was virtually nonexistent, and its cellular or molecular mechanism(s) of action remained a mystery." (See "Scientific Verdict Still Out" in the bibliography).