A recent study found concerningly high doses of the stimulant higenamine in some weight loss, energy and sports supplements sold in the U.S. Higenamine is a naturally-occurring stimulant which is permitted to be sold as a dietary supplement ingredient in the U.S. However, the substance is known to increase heart rate and have other serious cardiovascular effects when small doses (less than 5 mg) are taken intravenously, and there are no known studies on the effects of taking the large, oral doses found in many of the supplements that were tested. 

Researchers analyzed 24 supplements labeled as containing higenamine, or its synonyms, norcoclaurine or demethylcoclaurine. The amount of higenamine in the products ranged from less than 0.005 mg up to 62 mg per serving, and up to 110 mg per day if following recommended serving sizes. Of the five products that listed an amount of higenamine on the label, none were found to be accurate.

Higenamine occurs naturally in plants such as Aconitum carmichaelii (Sichuan aconite) and Nandina domestica (nandina fruit). Studies in China using small intravenous doses of higenamine (2 mg to 5 mg) have found it can increase heart rate and affect blood pressure, and is associated with side effects such as dizziness, headache, heart palpitations, shortness of breath and chest pain. There are two small studies on the effects of higenamine taken orally as a supplement, but both were funded by supplement manufacturers, and, due to design flaws, cannot be relied on to draw conclusions about the safety of higenamine (Lee, Lipids Health Dis 2013; Bloomer, Hum Exp Toxicol 2015). The substance was banned by the World Anti-Doping Agency in 2017.

See ConsumerLab.com's Review of Weight Loss Supplements for more about the safety of common ingredients used for weight loss.

To read the full study, use the link below.