Black Cohosh

Black Cohosh is a herb native to North America that has traditionally been used for cognitive and inflammatory conditions, but has grown in popularity due to it's ability to treat vasomotor symptoms of menopause; primarily hot flashes and night sweats. It is one of the most popular and highest sold supplements in the Western world (10^th place in 2008), according to some surveys.

Studies on the matter are highly mixed. The larger body of evidence favors the efficacy of Black Cohosh for treatment of vasomotor symptoms but consists largely of unblinded studies; as the placebo effect can reduce menopausal complaints, blinding is needed. Efficacy has been demonstrated with blinded studies on Black Cohosh as well, but many of them are confounded with consumption of other compounds. A few blinded studies on Black Cohosh without any other compounds have been conducted, and are basically split right down the middle on efficacy if not favoring 'no significant effects' a little bit more due to quality of data and sample size.

Beyond the questionable efficacy, Black Cohosh appears to be safe. It is non-estrogenic (despite being thought to influence estrogen in the past) and may act centrally (in the brain) via serotonin, dopamine or opioids. Stomach upset has been reported and seems to be attributable to Black Cohosh in some people, but reports of liver toxicity do not appear to be related to the Black Cohosh herb. These reports do exist, but they cannot be linked to Black Cohosh logically.

If using an isopropanolic extract (usually sold under the brand name of Remifemin), 20-40mg daily is used in doses of 20mg; taking 20mg results in a once daily dosing, whereas taking 40mg is twice daily dosing of the 20mg. This dosage (20-40mg) confers 1-2mg of triterpenoid glycosides.

If using an aqueous:ethanolic extract of black cohosh root (ie. not Remifemin) then doses range from 64-128mg daily which are usually taken in two divided doses. This contributed about the same amount of triterpenoid glycosides.

It is not known whether or not black cohosh needs to be taken with food, although it is sometimes recommended to do so out of prudency.

The Human Effect Matrix looks at human studies (it excludes animal and in vitro studies) to tell you what effects black cohosh has on your body, and how strong these effects are.

Grade	Level of Evidence [show legend]
	Robust research conducted with repeated double-blind clinical trials
	Multiple studies where at least two are double-blind and placebo controlled
	Single double-blind study or multiple cohort studies
	Uncontrolled or observational studies only

Level of Evidence ? The amount of high quality evidence. The more evidence, the more we can trust the results.	Outcome	Magnitude of effect ? The direction and size of the supplement's impact on each outcome. Some supplements can have an increasing effect, others have a decreasing effect, and others have no effect.	Consistency of research results ? Scientific research does not always agree. HIGH or VERY HIGH means that most of the scientific research agrees.	Notes
	Symptoms of Menopause	Minor	Very High See all 13 studies	Although there appears to be some benefit over placebo, more recent studies note that the magnitude of benefit is much less than previously though (in the past, a false positive occurred when unblinded studies noted remarkable benefits with black cohosh; the placebo effect appears to be quite potent in regards to menopause)
	Anxiety	-	- See study	The trial to measure anxiety related to menopausal symptoms failed to find a benefit associated with black cohosh
	Blood Glucose	-	- See study	No significant influence on blood glucose levels
	C-Reactive Protein	-	- See study	No significant alterations seen in C-RP with black cohosh
	Cognition	-	- See study	No significant influences on cognition in menopausal women has been noted
	Estrogen	-	- See study	No significant influences on circulating estrogen levels or biomarkers of estrogenicity (vaginal cytology)
	HDL-C	-	- See study	No significant influence on HDL-C
	Insulin	-	- See study	No significant influence on fasting insulin
	LDL-C	-	- See study	No significant effects on LDL-C
	Memory	-	- See study	No significant effect on memory function
	Triglycerides	-	Very High See 2 studies	No significant effect on triglyceride concentrations in serum
	Coronary Heart Disease Risk	Minor	- See study	A slightly increased chance of heart disease was said to occur in one study pairing black cohosh with exercise, and an increased risk was also determined in control but not in black cohosh in isolation.
	Subjective Well-Being	Minor	- See study	May increase well being in those with menopause if a reduction of symptoms occurs.
	Blood Flow	-	- See study	No significant influences on blood flow and vasodilation
	Blood Pressure	-	- See study	No significant influence on blood pressure
	Bone Mineral Density	-	- See study	No significant influence on bone mineral density
	Breast Density	-	- See study
	Liver Enzymes	-	- See study	No significant influence on liver enzymes
	Weight	-	- See study	No significant influences on body weight

Studies Excluded from Consideration

• Confounded with other herbs and phytoestrogens^[1][2][3]