|black cohosh side effects, black cohosh benefits
menopause, tea, extract, and dosage August 20, 2011
Section 1: Information extracted from National Institutes of Health, USA
Black cohosh (known as both Actaea racemosa and Cimicifuga racemosa), a member of the buttercup family, is
a perennial plant that is native to North America. Other common names include black snakeroot, bugbane,
bugwort, rattleroot, rattletop, rattleweed, and macrotys. Insects avoid it, which accounts for some of these
Black cohosh, extracts, preparations and dosage
Preparations of black cohosh are made from its roots and rhizomes (underground stems). One commercial
standardized black cohosh preparation is Remifemin, which contains black cohosh extract equivalent to 20 mg
of root per tablet. The manufacturer changed the formulation of this preparation from a solution (root extracted
with ethanol, 60% by volume) to tablets (root extracted with isopropyl alcohol, 40% by volume), complicating the
comparison of research results. Other preparations of black cohosh have been less well studied than Remifemin.
Extracts of black cohosh are standardized to 26-deoxyactein content, a member of a group of chemicals known
as saponins. Commercially available preparations of black cohosh usually contain 1 mg of total triterpene
saponins (expressed as 26-deoxyactein) in each 20-mg dose of extract.
black cohosh benefits
Historical uses of black cohosh
Black cohosh was used in North American Indian medicine for malaise, gynecological disorders, kidney
disorders, malaria, rheumatism, and sore throat. It was also used for colds, cough, constipation, hives, and
backache and to induce lactation. In 19th-century America, black cohosh was a home remedy used for
rheumatism and fever, as a diuretic, and to bring on menstruation. It was extremely popular among a group of
alternative practitioners who called black cohosh "macrotys" and prescribed it for rheumatism, lung conditions,
neurological conditions, and conditions that affected women's reproductive organs (including menstrual
problems, inflammation of the uterus or ovaries, infertility, threatened miscarriage, and relief of labor pains).
What clinical studies have been done on black cohosh and its effect on menopausal symptoms?
Black cohosh is used primarily for hot flashes and other menopausal symptoms. A number of studies using
various designs have been conducted to determine whether black cohosh affects menopausal symptoms. Few
were placebo-controlled studies, and most assessed symptoms by using the Kupperman index, a scale that
combines measures of hot flashes, insomnia, and depression but not vaginal dryness. Those with the best study
designs are described below.
A randomized, double-blind, placebo-controlled trial was done in breast cancer survivors because most of these
women experience hot flashes and many use complementary or alternative remedies. The women were over
age 18 and had completed breast cancer treatment at least 2 months before the trial; 85 women (69 of whom
completed the trial) took one tablet of placebo or dosage of 40 mg/day of black cohosh (as 20 mg twice daily)
for 2 months to determine the effect on hot flashes, excessive sweating, palpitations, headaches, poor sleep,
depression, and irritability [J.S. Jacobson, Columbia University, written communication, 2002]. Fifty-nine subjects
were using tamoxifen (an antiestrogen treatment for breast cancer); tamoxifen users were distributed almost
equally between the treatment and control groups. The frequency and intensity of hot flashes decreased in both
groups, with no statistical difference between the groups; excessive sweating decreased significantly more in the
treatment group than the placebo group. Other symptoms improved equally in both groups, and scores on a
health and well-being scale did not change significantly in either group.
A 24-week study in 60 women who had undergone hysterectomy but retained at least one ovary compared the
effects of 8 mg/day of a black cohosh extract (as four 2-mg tablets daily; isopropanol extract version of
Remifemin) with three estrogen regimens: estriol (1 mg/day), conjugated estrogens (1.25 mg/day), and
estrogen-progestin therapy (one daily Trisequens tablet containing 2 mg estradiol and 1 mg norethisterone
acetate) . In all groups a modified Kupperman index measuring additional physical symptoms was significantly
lower at 4, 8, 12, and 24 weeks after treatment began. Black cohosh decreased symptoms similarly to the other
treatments, but this study was not placebo controlled.
A randomized, double-blind, placebo-controlled trial in 80 menopausal women compared dosage 8 mg/day of a
black cohosh extract (as two 2-mg tablets of Remifemin twice daily) with placebo or conjugated estrogens
(dosage 0.625 mg/day). At 12 weeks, scores on the Kupperman index and the Hamilton anxiety scale were
significantly lower in the treated groups than in the placebo group; the scores of participants using black cohosh
were somewhat better than the scores of those receiving the estrogen treatment. This is one of the few studies
in which hot flashes were scored separately from other symptoms. Daily hot flashes decreased from 4.9 to 0.7 in
the black cohosh group, 5.2 to 3.2 in the estrogen group, and 5.1 to 3.1 in the placebo group.
A randomized, 12-week study of 55 menopausal women compared an ethanolic extract of black cohosh (dosage
40 drops twice daily) with conjugated estrogens (dosage 0.6 mg/day) or diazepam (dosage 2 mg/day) .
Regardless of the treatment, all symptoms improved as measured by the Kupperman index, a depression scale,
and an anxiety scale. However, this was not a blinded, placebo-controlled trial and diazepam is not a usual
treatment for menopausal symptoms.
Although some study results suggest that black cohosh may have benefit of relieving menopausal symptoms,
other study results do not. Studies of black cohosh have yielded conflicting data, in part because of lack of rigor
in study design and short study duration (6 months or less). In addition, interpretation of these studies is
complicated by the fact that different amounts of black cohosh from different sources were used in the various
studies and their outcome measures were different. To provide more definitive evidence on the effects of black
cohosh on menopausal symptoms. [Note: The purity of black cohosh, dosage form and composition of the black
cohosh preparation are also important.]
How does black cohosh work?
How black cohosh works is not known. The possibility that black cohosh exhibits estrogenic activity has been
studied but the evidence is contradictory.
A compound recently identified in black cohosh (fukinolic acid) was shown to have estrogenic activity in vitro
. Other active compounds appear to include triterpene glycosides (including actein and cimicifugoside),
resins (including cimicifugin), and caffeic and isoferulic acids.
Effect on hormone levels
Women who have reached menopause generally have lower levels of estrogen and higher levels of two other
hormones, luteinizing hormone (LH) and follicle-stimulating hormone (FSH), than do women who menstruate.
Three of four studies show that black cohosh does not affect LH or FSH.
A study of 150 perimenopausal and postmenopausal women using two different doses of black cohosh
(Remifemin tablets, dosage 39 or 127.3 mg/day) found that 6 months of treatment caused no changes in LH,
FSH, prolactin, estradiol, or sex-hormone-binding globulin. Another trial of black cohosh in women with breast
cancer found small but insignificant changes in LH levels (in 18 subjects) and FSH levels (in 33 subjects) . In
the third study, Remifemin (dosage 8 mg/day given as four 2-mg tablets) did not affect LH or FSH levels in 15
women who had undergone a hysterectomy who were part of a study comparing black cohosh with several
The fourth study, which found an effect of black cohosh on LH levels, was a trial in 110 women with menopausal
symptoms. Participants treated with Remifemin (dosage 8 mg/day) for 8 weeks had significantly lower average
LH levels than did a control group (FSH levels were unchanged). However, the report of this study does not
include the participants' hormone levels before the study began, so the two groups may have had different LH
In vitro studies used to examine the effect of black cohosh have given contradictory results. Black cohosh had
no activity in estrogen receptor (ER) binding assays in Ishikawa (endometrial) and S30 (breast cancer) cell
lines. It did not show potent ER binding activity; slightly enhanced the growth of ER-positive breast cancer cells
(T47D) but was not tested on ER-negative cells. In another study black cohosh inhibited the growth of T47D
(human breast cancer) cells. In ER-positive breast cancer cell line 435, black cohosh resulted in growth
inhibition. In ER-positive breast cancer cell line MCF-7, it inhibited estradiol-induced stimulation of cell
proliferation in one study but isolated constituents of black cohosh increased proliferation in another.
Effect on the vagina
Because of the marked changes in hormone levels in women who have achieved menopause, numerous
modifications occur in the structure and activity of vaginal and uterine tissues. Microscopically, vaginal cells look
different after menopause because of decreased estrogen. Studies have been mixed on whether black cohosh
affects vaginal epithelium. One placebo-controlled, double-blind trial of black cohosh showed estrogenic
changes in vaginal epithelium of menopausal women , but another study of two Remifemin doses (39 or 127.3
mg/day) found that 6 months of treatment in perimenopausal and menopausal women caused no changes in
vaginal cytology .
Effect on the uterus
Menopause is associated with a thinning of the uterine lining (the endometrium). No human studies have
adequately evaluated the effect of black cohosh on uterine endometrium.
When uterine weight of immature female mice and growth of ER-positive breast cancer cells (MCF-7) were used
to measure the estrogenic effect of black cohosh, black cohosh caused an increase in uterine weight and
growth of cancer cells in culture, which the authors said reflected an estrogenic effect. Black cohosh did not
exhibit estrogenic effects in a study that measured uterine weight in immature mice and vaginal cell cornification
(conversion of cells from columnar to squamous) in ovariectomized rats.
black cohosh side effects
Side Effects of Black cohosh include stomach discomfort and headaches. Clinical trials comparing estrogens
with black cohosh preparations have shown a low incidence of side effects associated with black cohosh;
headaches, gastric complaints, heaviness in the legs, and weight problems were the main side effects noted.
A published case of acute hepatitis involved a 47-year-old woman who used black cohosh for symptoms of
menopause. She received a liver transplant three weeks after she started taking the herb. The report indicated
the dose of black cohosh did not exceed the dosage recommended on the package; but no other dosage
information was provided. No other cause for liver disease was found.
Black cohosh usually has not been used for long periods, and published studies have followed women for only 6
months or less. Recently, a large study that followed postmenopausal women taking combined estrogen and
progestin for an average of 5.2 years showed a small but significant increase in the risk of certain diseases,
demonstrating the importance of long-term studies in revealing risks that may not be apparent in shorter
studies. If black cohosh is estrogenic, long-term use may adversely affect uterine or breast tissue. No studies
have been published on long-term safety in humans, particularly regarding abnormal stimulation of cells in the
endometrium or breast.
There is a case report of neurological complications in a postterm baby after labor induction with a mixture of
black cohosh and blue cohosh (Caullophylum thalictroides) during a home birth.
Other cases of adverse outcomes experienced by neonates born to women who reportedly used blue cohosh to
induce labor have been published in peer-reviewed journals.
Black cohosh side effects may be serious, if there is. Liver damage has been reported in a few individuals
using black cohosh, but millions of people have taken the herb without apparent side effects. While studies of
black cohosh have not provided scientific evidence to show that the herb causes liver damage, one country has
added a warning to the label of all products containing black cohosh, stating that it may cause harm to the liver
of some individuals and should not be used without medical supervision.
In the United States, the U.S. Pharmacopeia (the standards-setting organization for foods and drugs) advises
that black cohosh products be labeled with the following cautionary statement: "Discontinue use and consult a
healthcare practitioner if you have a liver disorder or develop symptoms of liver trouble, such as abdominal
pain, dark urine, or jaundice" .
Who should not take black cohosh?
* The use of black cohosh during pregnancy has not been rigorously studied. Thus, it would be prudent for
pregnant women not to take black cohosh unless they do so under the supervision of their health care provider.
* Women with breast cancer may want to avoid black cohosh until its effects on breast tissue are understood.
* Individuals with liver disorders should avoid black cohosh.
* Individuals who develop symptoms of liver trouble such as abdominal pain, dark urine, or jaundice while taking
the supplement should discontinue use and contact their doctor.
Does black cohosh interact with any drugs or laboratory tests?
Although black cohosh has not been reported to interact with any drugs or to influence laboratory tests, this has
not been rigorously studied.
Section 2 Research Abstracts
The NIH article is so detail, probably, I don't need to prepare on black cohosh side effects or benefits. However,
I would like to share a few interesting research abstracts about black cohosh side effects or benefits with you:
Abstract 1 Spontaneous reports of assumed herbal hepatotoxicity by black cohosh: is the
liver-unspecific Naranjo scale precise enough to ascertain causality? Pharmacoepidemiol Drug Saf. 2011
Teschke R at Teaching Hospital of the Goethe University Frankfurt/Main, Germany, used the liver-specific scale
of the updated Council for International Organizations of Medical Sciences (CIOMS) as well as the Naranjo
scale that is not organ specific and therefore not liver specific. Both scales were applied to 22 cases of
spontaneous reports with initially assumed herbal hepatotoxicity caused by black cohosh, used for menopausal
symptoms. The analysis shows that causality was either unlikely (n = 6) or excluded (n = 16), using the updated
CIOMS scale. There were various confounding variables: pre-existing liver diseases (n = 6) including genuine
autoimmune hepatitis or alcoholic or cardiac hepatopathy; hepatotoxicity induced by interferon or fluoxetine (n =
2); marginally increased serum activities of alanine aminotransferase (n = 2) or gamma-glutamyltranspeptidase
(n = 2) of unassessable causality; a mixed group consisting of unassessable cases (n = 6) and cases with
questionable, poorly documented hepato-biliary diseases (n = 3); and rosuvastin-induced rhabdomyolysis (n =
1). These confounding factors were not recognized by the Naranjo scale. Conclusion Applying the updated
CIOMS scale to cases with initially assumed hepatotoxicity by black cohosh, causality was now found either
unlikely or excluded.
Abstract 2 Herb induced liver injury presumably caused by black cohosh: a survey of initially purported
cases and herbal quality specifications. Ann Hepatol. 2011 Jun 1;10(3):249-59.
Teschke R, same author for Abstract 1, analyzed and reviewed all published case reports and spontaneous
reports of initially alleged BC hepatotoxicity and they concluded that the use of BC may not exert an overt
hepatotoxicity risk, but quality problems in a few black cohosh products were evident that require additional
regulatory quality specifications.
Abstract 3 Suspected black cohosh hepatotoxicity: no evidence by meta-analysis of randomized
controlled clinical trials for isopropanolic black cohosh extract.
Five studies involving a total of 1,117 women were included in the meta-analyses. A total of 1,020 women (test
population=517 and reference population=503) completed the studies. Perimenopausal and postmenopausal
women (40-60 y) were treated daily with iCR (corresponding to 40-128 mg drug) for 3 to 6 months. The
meta-analyses of the standardized mean differences in the "test" versus "reference" showed no significant
effects and no differences between double-blind, placebo-controlled and other trials. The overall fixed effect ±
SEM was 0.055 ± 0.062 (P=0.37) for aspartate aminotransferase and 0.063 ± 0.062 (P=0.31) for alanine
aminotransferase. The nonsignificant effects concerned the overall analyses of all included studies as well as
the proportion of placebo-controlled studies. CONCLUSIONS: The results of this meta-analysis of five
randomized, double-blind, and controlled clinical trials showed no evidence that iCR has any adverse effect on
Discuss with your doctor before taking any alternative medicine. This article is for
reference only, it is not a medical advice.