The highest risk dietary supplement products are human hormones such as DHEA, andostenedione and melatonin. These are important chemical messengers in the human body with significant effects on how the body works.

Many human hormones are important and fully regulated prescription drugs, with great benefits and substantial risks requiring careful medical management. Insulin-an essential and lifesaving drug for Type 1 diabetes-can also produce a loss of consciousness and coma. Estrogen, unopposed by progesterone, is a growth promoter and proven carcinogen. It causes endometrial cancer, and possibly other cancers. Thyroid hormone, important and safe replacement hormone for millions, caused heart attacks when used in a different form to lower cholesterol. But because of a loophole in the 1994 law, many human hormones are available as dietary supplements-typically those about which the least is known.

Annette Dickinson, the industry group official, had reservations about the wisdom of including hormones under the permissive laws for dietary supplements.

"I do have some concerns, about hormones generally. I frankly wish we could not include them in this category. One needs to handle those very carefully. The manufacturer needs to be very cautious about dose and purity. Consumers need to be well informed and cautions about what they use."

Although Dickinson mentioned the importance of purity in hormones, a study at the Mayo Clinic provided no reassurance. Biochemist Stephen Naylor bought four different brands of melatonin, a powerful hormone whose functions are poorly understood, but is sold as a sleep aid and as one bestseller put it, a "miracle age-reversing, disease fighting and sex-enhancing compound." He subjected all four brands to mass spectrometry analysis with High Performance Liquid Chromatography. He found three of the four products contained a total of seven different contaminants. Two of the contaminants were similar to those in l-tryptophan-linked to EMS cases. But whether these two chemicals can cause EMS or another health disorder remains unknown, Naylor said.

But is there any margin of safety because of melatonin's natural origin? "Chemistry is chemistry," Naylor said. "Whether you're extracting a hormone from a plant, or chemically synthesizing it, the moment you start to handle a chemical like melatonin, it is going to undergo other chemical reactions, and add whole new dimension to biological and toxicological activity. That is just reality."

Among athletes and body builders a popular hormone is androsenedione, which zoomed to superstar status with fame of home run champion Mark McGwire. (I found more than 1,000 media articles mentioning the two.) Like testosterone, it is a male sex hormone, and the body may convert it to testosterone.

"Testosterone causes liver cancer," said Raymond Woosley, chairman of the Department of Pharmacology at Georgetown University Medical Center. "It's great if it is in your gonads, but not if it is in your liver. If you take it orally, that's where it goes."