Black Cohosh a Bust for Hot Flashes
Millions of women have taken black cohosh to reduce hot flashes and other menopause-related symptoms, but the most rigorous study of the herbal supplement ever conducted shows no evidence that it works.
WebMD News Archive
Dec. 18, 2006 -- Millions of women have taken black cohosh to reduce hot
flashes and other menopause-related
symptoms, but the most rigorous study of the herbal supplement ever conducted
shows no evidence that it works.
The federally funded trial was designed to compare black cohosh to other
herbal supplements, traditional hormone therapy, and placebo treatment for
Hormone therapy was the only treatment that clearly reduced hot flashes,
night sweats, and other related symptoms.
The study appears in the Dec. 19 issue of the journal Annals of Internal
"Our finding that black cohosh did not work will be disappointing news
to many women," researcher Katherine M. Newton, PhD, tells WebMD. "It
would be nice to find a clearly effective alternative to hormone
Looking for Alternatives
Most women experience hot flashes and related symptoms around the time of
menopause, which typically occurs between ages 45 and 55.
Hormone therapy involving estrogen or estrogen plus progestin is very
effective for reducing hot flashes, but concerns about safety have caused
millions of women to abandon the treatment.
Those concerns appeared to be bolstered late last week with the news of a
dramatic drop in breast cancers among American women.
Although the reason for the drop is not yet clear, many experts speculate
that it is related to the decline in hormone use following the 2002 publication
of the Women's Health Initiative study, which found an increase in both breast
cancers and heart problems among users.
Many symptomatic women turned to black cohosh and other herbal supplements
when they stopped taking hormones, but few well-designed clinical trials have
been done evaluating the effectiveness of these products.
Studying Treatments for Menopause Symptoms
In an effort to address this, Newton and colleagues with the Seattle-based
health care system Group Health Cooperative recruited 351 menopausal and newly
postmenopausal women for their study.
The women were between the ages of 45 and 55 when they entered the trial,
and all were experiencing at least two menopause-related symptoms a day.
Without knowing which treatment they were getting, all of the women took one
of five therapies for a year. The treatments were:
- Black cohosh alone (160 milligrams daily)
- A combination herbal supplement that included 200 milligrams of black
cohosh daily, plus alfalfa, boron, dong quai, ginseng, and other herbal
- A combination herbal supplement that did not include black cohosh but did
include recommendations to increase the consumption of soy-based foods
- Traditional hormone therapy
The researchers found no significant difference in the number of daily hot
flashes experienced by women on any of the treatments, with the
exception of hormone therapy.
Women taking herbal supplements had an average of half a hot flash a day
less than women taking placebo -- an amount not considered significant. By
comparison, the women on hormone therapy had about four fewer hot flashes a