Boston—The World Anti-Doping Agency (WADA) added higenamine to its list of substances prohibited in sports about 2 years ago.

Now, a new study has found that inaccurately labeled and potentially harmful levels of the stimulant are in weight-loss and sports/energy supplements available in the United States. The article, published in Clinical Toxicology, has useful charts to help pharmacists determine which products contain higenamine.

Conducted by Harvard Medical School researchers, the independent study involved the global public health organization NSF International, and the National Institute for Public Health and the Environment (RIVM) in the Netherlands.

“We’re urging competitive and amateur athletes, as well as general consumers, to think twice before consuming a product that contains higenamine,” said coauthor John Travis of NSF International. “Beyond the doping risk for athletes, some of these products contain extremely high doses of a stimulant with unknown safety and potential cardiovascular risks when consumed. What we’ve learned from the study is that there is often no way for a consumer to know how much higenamine is actually in the product they are taking.”

All supplements labeled as containing higenamine or a synonym (i.e., norcoclaurine or demethylcoclaurine) that were available for sale in the U.S. were identified. For each brand, one sample was analyzed by NSF International in Ann Arbor, MI, and one sample by the RIVM in the Netherlands.

In the 24 products analyzed overall, 46% of the supplements with higenamine were marketed as weight-loss products, with an equal percentage designated as sports/energy supplements.

Researchers pointed out that two brands did not list a labeled indication.
The quantity of higenamine (±95% CI) ranged from trace amounts to 62 ± 6.0 mg per serving, the study team reported, adding, “Consumers could be exposed to up to 110 ± 11 mg of higenamine per day when following recommended serving sizes provided on the label.”

While five products—21%—listed an amount of higenamine contained in the product, none were accurately labeled, with the quantities in the supplements ranging from <0.01% to 200% of the amounts listed on the labels, the study noted.

“Some plants, such as ephedra, contain stimulants. If you take too much of the stimulants found in ephedra, it can have life-threatening consequences. Similarly, higenamine is a stimulant found in plants,” explained lead author Pieter Cohen, MD, associate professor of medicine at Harvard Medical School and an internist at Cambridge Health Alliance. “When it comes to higenamine, we don’t yet know for certain what effect high dosages will have in the human body, but a series of preliminary studies suggest that it might have profound effects on the heart and other organs.”

“While higenamine is considered a legal dietary ingredient when present as a constituent of botanicals, our research identified concerning levels of the stimulant and wildly inaccurate labeling and dosage information,” Travis emphasized, “And, as a WADA-prohibited substance, any amount of higenamine in a dietary supplement should be of concern to the competitive athlete.”

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