To begin -- it’s called melatonin. Not to be confused with melanin, the pigment responsible for darkening the skin of blacks like me. And not a chemical extracted from watermelon, as thought by a writer friend who shall remain nameless.

For those of you who’ve missed the recent spate of newsmagazine cover stories, melatonin is a hormone manufactured in the brain’s pineal gland. Touted as the body’s “natural wonder drug,” melatonin is now being pitched everywhere from hippie health-food stores to megachain GNC as a potent antioxidant with benefits for people experiencing a wide range of health problems, including cancer, heart disease, cataracts, diabetes, insomnia and HIV infection.

Melatonin is easily synthesized and available over-the-counter at pharmacies and health food stores. A bottle of 60 three-milligram tablets set me back $10 when a colleague recommended that I take melatonin (which jumpstarts the body’s sleep rhythms) to counter mind-numbing jet lag. It helped.

Melatonin is definitely emerging as one of the hottest health topics of the decade. But what real benefits, if any, might melatonin provide for people with HIV? Are there side effects? Should melatonin -- which is not regulated by the Food and Drug Administration (FDA) -- be added to the regimen of people with HIV, some of whom are already downing dozens of pills daily? Once again, no one really knows.

So I asked a PWA why he takes it. Jason Lorgan, 26, an administrator at San Diego State University, believes that “melatonin enhances the immune system and may actually slow down the replication of the AIDS virus. The only side effect I’ve had is that it’s given me a good night’s sleep. I can live with that.”

A handful of physicians have written about melatonin, and some of those books are better than others. Generally considered one of the best is also the newest, Melatonin: Your Body’s Natural Wonder Drug. Author Russel J. Reiter, Ph.D., a professor of neuroendocrinology at the University of Texas Health Science Center at San Antonio, suggests that melatonin may help battle HIV by destroying free radicals -- toxic, noxious molecules that wreak havoc on the immune system.

“The AIDS research shows that melatonin scavenges very effectively against free radicals,” Reiter says, his warm, down-home lilt fitting for a sleeping-aid expert. “It stimulates the immune system. And with a disease where there are no ready cures, keeping the immune system strong is of utmost importance. It may not help every HIV positive person. But it probably won’t hurt. The worst-case scenario is that it will have a neutral impact.”

Reiter readily admits that most of the research on melatonin has been conducted on laboratory mice. To date, there have been no formal studies of the hormone in humans, he says, let alone specifically in people with HIV. In fact, the FDA threatened to pull melatonin off the shelves in 1994 because not enough studies had been done to substantiate its growing reputation as the best natural sleeping pill on the block. Instead, the agency put out a warning.

The warning was no doubt prompted by the tryptophan catastrophe in the late 1980s. Tryptophan is an essential amino acid that had gained wide popularity as a natural antidepressant. It was banned by the FDA after contaminated lots led to the deaths of more than two dozen people (which is similar to banning automobiles because a certain vintage of Ford Pinto explodes when hit from the rear). Still, without human studies, how can melatonin supporters be assured that it won’t put folks into, shall we say, the mother of all sleeps?

Dr. Ray Sahelian, author of Melatonin: Nature’s Sleeping Pill, goes back to the mice: “I can say that melatonin has been around two to three billion years and that the lab studies done on mice are impressive.” Sahelian, a Los Angeles family practitioner, then cites a recent study in which two groups of mice were injected with the virus that causes encephalitis. One group of mice was treated with melatonin. The other group was not. The mice on melatonin lived longer. “So in the short term, it appears that the hormone boosts the immune system [in mice],” he says. “The long-term consequences of taking melatonin are clearly a gamble, but if I had AIDS, I would consider taking a milligram every night.”

Portland writer Julie Huffaker gives melatonin high marks in her book, The Fearless Flyer. “There is a whole new research frontier before us. What we know at this point is that melatonin is nonaddictive, nontoxic and inexpensive. That’s saying a lot,” she says.

Already, however, the experts disagree. Sahelian says that morning grogginess, daytime fatigue, headaches and mild depression are among the side effects that some patients using melatonin have noted.

The specter of side effects doesn’t faze Jason Lorgan. “Melatonin is cheaper than multivitamins. It helps me sleep when I’m stressed out. I think the benefits outweigh the risks.” But at this point, it’s strictly a personal gamble.