Black Cohosh Not Always What It Seems
Study Shows Some Supplements Sold as Black Cohosh Contain Other Herbs
WebMD News Archive
April 26, 2006 -- Women who take black cohosh supplements to treat hot
flashes and other symptoms related to menopause may not be
getting what they pay for, new research shows.
A chemical analysis of 11 commercially available products marketed as black
cohosh found that three did not even contain the herb, which is grown in North
America. Instead, researchers say, these products contained a related Asian
species of the plant that differs not only chemically but also in its clinical
uses compared with the North American species. Importantly, the imposter is
also cheaper to produce.
One other product contained both the genuine black cohosh and the Asian
imitator. And the seven products that contained only black cohosh had widely
varying amounts of the compounds thought to be the active agents for the relief
of menopause symptoms.
The findings are published in the May 17 issue of the Journal of
Agricultural and Food Chemistry.
"The variability between products with black cohosh wasn't too
surprising, but the fact that some of these products did not even contain black
cohosh was both surprising and worrisome," says researcher Edward J.
Kennelly, PhD, of Lehman College and the City University of New York.
Kennelly tells WebMD that the tested products were found in stores in New
York City between 2002 and 2004 and were thought to be representative of what
was available in the area at the time.
The researchers used a sophisticated testing technique to determine if the
products contained black cohosh or the related Asian species.
Although the Asian plant has been used in Chinese medicine for centuries,
Kennelly says it is not used for the same indications as black cohosh.
The researchers did not identify the 11 products they tested by brand, but
they did notify the FDA of their findings, Kennelly says.
A spokesman for a leading trade group for the botanical products industry
tells WebMD that the group was made aware a little over a year ago that some
extracts used in the manufacture of black cohosh supplements did not contain
genuine black cohosh.
Steven Dentali, PhD, says a manufacturer warned the American Herbal Products
Association (AHPA), and the group quickly took action to make sure other
manufacturers knew that the extracts were out there.
It has also identified an inexpensive method that can be used by the
industry to identify the cheaper Asian extracts.
Dentali is vice president of scientific and technical affairs for the
How Can Consumers Tell?
While it isn't always easy for consumers to know what they are getting when
they buy botanical products like black cohosh, Dentali says herbal products
that seem too cheap may be suspect.
"It is true that sometimes you do get what you pay for," he says.
"Most of the better-known brands have invested in making sure that their
supply chain is secure. They would not dream of buying extracts from
questionable sources to manufacture their products."