Bellanti and his colleagues theorize that CFS is nothing more than a lack of the chemical adenosine triphosphate (ATP), which provides power to the body. Chronic infections, stress, and other ailments tend to deplete the chemical, according to the researchers. NADH, short for nicotinamide adenine dinucleotide, is the chemical that jump-starts the production of ATP in muscles, so the researchers hypothesized that simply providing supplements of the chemical might benefit people with chronic fatigue.

Patients in the study received 10 milligrams of NADH a day. "They may have stumbled onto something useful,' said Ronald Glazer, a virologist and immunologist at Ohio State University School of Medicine. He argued that so little is currently available to treat the syndrome that CFS patients should consider taking the supplement now. "These people are really suffering,' said Glazer, whose own work on the causes of the disease was published last year in the Journal of the American Medical Association.

Both Glazer and the study authors agreed that more clinical trials of NADH must be conducted to confirm the results of the study. One physician who regularly treats many patients with CFS, Dr. Jacob E. Teitelbaum of Annapolis, Md., said he already prescribes the supplement to his patients, along with a regimen of exercise, vitamins, antibiotics and sleep therapy.