Researcher calls for stimulant herb rethink

US researchers have highlighted increasing numbers of adverse events for products containing extracts of the yohimbe herb which is sold in both the dietary supplement and pharmaceutical channels.

They called for a re-assessment of the herb’s status.

The yohimbe extract – typically known as yohimbine – has become increasingly popular as the active ingredient in weight management/energy products as well as products that target the erectile dysfunction market. This rise in popularity has been matched by a rise in adverse events the researchers observe, at least in California.

They pointed to 238 cases reported to the California Poison Control System with gastrointestinal distress (46%), tachycardia (43%), anxiety/agitation (33%), and hypertension (25%) the most common symptoms. Some reported multiple symptoms.

The research, published this month in The Annals of Pharmacotherapy, is led by Christine Haller, who is the medical director of the department of global regulatory affairs and safety at San Francisco pharma firm, Amgen.

Haller used to work at the University of California San Francisco Department of Clinical Pharmacy where she researched both orange bitter and ephedra – other herbal stimulants that have been linked to raised adverse event numbers.

Ephedra has been banned by the Food and Drug Administration since 2004.

Her team noted that the number of yohimbe-related adverse events rose from 1.8 cases to 8 cases per 10,000 adult exposures between 2000 and 2006.

“A reexamination of whether yohimbine should be considered a "safe" dietary supplement under the Dietary Supplement Health and Education Act is warranted,” they wrote.

Warnings

The founder and executive director of the American Botanical Council, Mark Blumenthal, said yohimbe and its extracts had been on the market for more than 25 years – with intended uses varying from psychiatric to erectile to weight loss.

He said the rise in adverse events could be related to the increased popularity of the products, but it could equally be down to a deterioration in quality.

“But this is a potent herb and products should contain warnings about potential contraindications,” he said. “Responsible products makers will list such cautions but I am not sure all products out there are being marketed in a totally responsible way.”

Drug?

Frank Jaksch, the president of third party tester Chromadex, said his company had been following yohimbe and its extracts.

Yohimbine HCl is a drug, however you will still find it listed as an active ingredient in many supplements,” he said.

“Many companies claim to be adding an extract of Yohimbe, when in fact they are adding 99 percent Yohimbine HCl. If taken in low doses, there will not usually be a problem. If the dosing is too high, adverse events pop up pretty quickly, as yohimbine is pretty potent stuff.”