Consumers should avoid all nutritional supplements containing the natural stimulant higenamine, according to a new study from Harvard University.
“If it lists higenamine on the label, don’t purchase it,” said Pieter Cohen, an associate professor at Harvard Medical School in Boston, who led the new research, published in the journal Clinical Toxicology. Norcoclaurine and demethylcoclaurine are different names for the same botanical ingredient.
Cohen and his colleagues found higenamine in 24 readily-available supplements, mostly marketed for weight loss and energy boost. In some cases, doses were a dozen times larger than has ever been tested in people.
The World Anti-Doping Agency (WADA) banned higenamine last year as a performance-enhancing substance.
Sales of dietary supplements and multivitamins reached $20.7 billion last year in the United States, according to Euromonitor International, which tracks the industry but not sales of specific ingredients.
There hasn’t been much research into higenamine, but what there has been shows it can powerfully speed up the heart, much like the supplement ephedra that was taken off the market by the U.S. government in 2004 for causing strokes and heart attacks.
In China, where most of the research has taken place, scientists use higenamine in heart stress tests, because it puts extra strain on the heart to pump blood, said Cohen, also an internist with the Cambridge Health Alliance.
Higenamine has been mainly delivered directly into the blood stream at doses of around 2.5 to 5 milligrams, he said.
But over-the-counter products are sold without any dosage information, so consumers don’t know how much they’re getting. And Cohen’s analysis reveals that some supplements contain as much as 60 mg of higenamine per serving – and over 100 mg per day.
Swallowing higenamine rather than having it injected into the bloodstream probably cuts down on the amount that reaches the heart, Cohen said, but there are no reputable studies showing the safety of taking higenamine by mouth at doses above 5 mg.
Although most competitive athletes stopped using higenamine after it was banned, it’s still on the shelves. Kamal Patel, co-founder of Examine.com, an independent database of nutrition and supplement evidence, said he thinks non-athletes may still be using it as an alternative cough and asthma treatment, and he’s heard of people “stacking” higenamine with caffeine and other ingredients to promote fat loss.
Endurance athletes looking for a quick boost might take it too, he said, “although the half-life is really short, which limits its usefulness for many endurance activities.”
The supplement has never been studied for weight loss, and Cohen said he can’t see how it would help someone lose weight, although a faster heart rate might make someone think it is doing something. “It seems like a crazy way to try to lose some weight,” Cohen said.
Federal regulations require that manufacturers understand the safety of ingredients as directed for use on a product label, said Duffy MacKay with the Council for Responsible Nutrition, a Washington, D.C.-based trade and lobbying group. His organization maintains a database called Supplement OWL for companies to voluntarily make their ingredient lists available to the public and to provide confidential information to government regulators.
Higenamine may be a case, he said, where government regulators should step in and explore the data.
But everyone bears some responsibility for the appropriate use of supplements, he said.
“Consumers have a part to not be gullible, in the area of weight loss in particular,” MacKay said. “And make sure they do buy from brands they know and trust and talk to their doctors – and just not get pulled into one of these products that makes us all look bad.”
Cohen said people should avoid supplements that suggest they’ll boost workout performance, particularly if they contain higenamine. “Because this is only one of dozens of ingredients that will likely have real effects, but you don’t know how much you’ll get,” he said. Plus, there’s likely no research on how the ingredients interact. “These aren’t just benign placebos, they’re often potent drugs,” he said.