Black Cohosh is the most popular supplement for menopause in North America, but the results of human studies are mixed. It holds some benefits for controlling hot flashes and night sweats.
Black Cohosh is most often used for
Black cohosh (Cimicifuga racemosa) is a perennial dicot plant from the buttercup family (Ranunculaceae), and is native to North America, spanning from Canada to Georgia. Its roots and rhizomes (underground stems) are utilized in supplements. Black cohosh extracts can vary considerably depending on factors such as cultivation, harvesting, extraction techniques, solvent used, and standardization methods.
The rhizomes of black cohosh are typically harvested during early autumn once the flowers have turned to fruit and the leaves have withered. The harvested rhizomes are cut into segments, dried, and propagated in spring to create new plants.
The main active compounds in black cohosh, sometimes referred to as triterpene glycosides, include cycloartanol compounds (e.g., acteol, actein), cimigenol, and cimicifugoside. Other bioactives include flavonoids, (E)-isoferulic acid, dopargine (a derivative of dopamine), cimipronidine, salsolinol, and N(omega)-methylserotonin.
Research on black cohosh primarily focuses on its potential benefits for perimenopause and postmenopause symptoms.
One meta-analysis revealed that the isopropanolic extract of black cohosh (iCR) was found to be more effective than placebo in alleviating neurovegetative symptoms (e.g., hot flashes, night sweats, palpitations) and psychological symptoms (e.g., depression) in women with natural perimenopausal and postmenopausal symptoms. One of the studies within this meta-analysis also found that black cohosh improved sleep efficiency and decreased wake after sleep onset (WASO) compared to placebo.
For women undergoing iatrogenic menopause (i.e., menopause brought about by medical interventions such as hysterectomy), the effects of black cohosh are inconsistent. In one placebo double-blind RCT menopausal women with breast cancer (many undergoing tamoxifen treatment) who received iCR for 2 months did not exhibit a significant reduction in the intensity and count of hot flashes compared to placebo. However, they reported notably-reduced night sweating. It’s important to note that this study suffered from a small sample size and a high dropout rate, with hot flashes being self-reported by the participants. That said, longer-duration open studies (12–24 weeks) also have demonstrated significant reductions in induced hot flashes, sweating, and psychological symptoms in participants taking iCR.
To validate these findings, more extended RCTs that assess climacteric symptoms (i.e., symptoms of perimenopause, menopause and/or postmenopause) using objective measurements (e.g., increases in heart rate, finger blood flow, respiratory exchange ratio, skin temperature, and core body temperature) instead of self-reported questionnaires are essential.
Black cohosh is generally considered safe, and clinical studies did not report significant side effects.
The administration of standard or high doses of black cohosh over 3–6 months does not appear to impact liver function. Likewise, black cohosh shows no significant effects on blood pressure, heart rate, body weight, or body mass index (BMI). Studies have also explored its impact on kidney function, total cholesterol, and triglycerides, revealing no overall effects except for a few studies reporting instances of increased high-density lipoprotein (HDL) cholesterol and decreased low-density lipoprotein (LDL) cholesterol. Furthermore, trials comparing black cohosh to tibolone (a medication used to treat menopausal symptoms) found that people taking black cohosh exhibited fewer side effects (e.g., vaginal bleeding, spotting) than those taking tibolone.
One meta-analysis indicated that 0.5% to 15% of menopausal women taking black cohosh experienced gastrointestinal discomfort.
One animal study, coupled with in vitro testing on human cells, found that both in rats and in vivo black cohosh induced micronuclei (MN), which are biomarkers of genetic alterations, while also disrupting the folate pathway. This disruption led to non-regenerative macrocytic anemia in rats, characterized by enlarged red blood cells and inadequate bone marrow red blood cell replacement. Although these results indicate a potential risk associated with taking black cohosh, clinical studies are required to examine the impact on the human body.
Initially, the presumed mechanism of black cohosh involved the activation of estrogen receptors. However, both in vitro and in vivo studies on black cohosh extracts yielded no evidence of estrogenic activity. Instead, it appears that black cohosh binds to receptors in the central nervous system responsible for functions like thermoregulation, mood, and sleep (e.g., mu-opioid, serotonin, dopamine, c-aminobutyric acid). This mode of action clarifies why black cohosh does not influence estrogen levels, breast tissue density or proliferation, endometrial thickness, or vaginal cytology.
Additionally, black cohosh showed anti-estrogenic properties in breast cancer studies. This anti-estrogenic effect was observed in vitro as a reduction in the growth of estrogen-responsive breast cancer cells.
Another in vitro study found a potential nonestrogenic thermoregulatory mechanism of black cohosh, which may modulate the immune system by promoting nitric oxide (NO) production in cells treated with interferon gamma (INF-gamma).
- Cimicifuga racemosa
- Black Snake Root
- Blue Cohosh (completely different herb)
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.
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- Menopausal Symptoms - Karel Raus, Cosima Brucker, Christoph Gorkow, Wolfgang WuttkeFirst-time proof of endometrial safety of the special black cohosh extract (Actaea or Cimicifuga racemosa extract) CR BNO 1055Menopause.(Jul-Aug 2006)
- Menopausal Symptoms - Shams T, Setia MS, Hemmings R, McCusker J, Sewitch M, Ciampi AEfficacy of black cohosh-containing preparations on menopausal symptoms: a meta-analysisAltern Ther Health Med.(2010 Jan-Feb)
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- Menopausal Symptoms - Ross SMMenopause: a standardized isopropanolic black cohosh extract (remifemin) is found to be safe and effective for menopausal symptomsHolist Nurs Pract.(2012 Jan-Feb)
- Menopausal Symptoms - Newton KM, Reed SD, LaCroix AZ, Grothaus LC, Ehrlich K, Guiltinan JTreatment of vasomotor symptoms of menopause with black cohosh, multibotanicals, soy, hormone therapy, or placebo: a randomized trialAnn Intern Med.(2006 Dec 19)
- Menopausal Symptoms - Pockaj BA, Gallagher JG, Loprinzi CL, Stella PJ, Barton DL, Sloan JA, Lavasseur BI, Rao RM, Fitch TR, Rowland KM, Novotny PJ, Flynn PJ, Richelson E, Fauq AHPhase III double-blind, randomized, placebo-controlled crossover trial of black cohosh in the management of hot flashes: NCCTG Trial N01CC1J Clin Oncol.(2006 Jun 20)
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- Estrogen - Liske E, Hänggi W, Henneicke-von Zepelin HH, Boblitz N, Wüstenberg P, Rahlfs VWPhysiological investigation of a unique extract of black cohosh (Cimicifugae racemosae rhizoma): a 6-month clinical study demonstrates no systemic estrogenic effectJ Womens Health Gend Based Med.(2002 Mar)
- Anxiety Symptoms - Amsterdam JD, Yao Y, Mao JJ, Soeller I, Rockwell K, Shults JRandomized, double-blind, placebo-controlled trial of Cimicifuga racemosa (black cohosh) in women with anxiety disorder due to menopauseJ Clin Psychopharmacol.(2009 Oct)
- Subjective Well-Being - Maria Dolores Juliá Mollá, Yolanda García-Sánchez, Alberto Romeu Sarri, Faustino R Pérez-lópezCimicifuga racemosa treatment and health related quality of life in post-menopausal Spanish womenGynecol Endocrinol.(2009 Jan)
- Menopausal Symptoms - Ahmed Nasr, Hanan NafehInfluence of black cohosh (Cimicifuga racemosa) use by postmenopausal women on total hepatic perfusion and liver functionsFertil Steril.(2009 Nov)
- Menopausal Symptoms - Jacobson JS, Troxel AB, Evans J, Klaus L, Vahdat L, Kinne D, Lo KM, Moore A, Rosenman PJ, Kaufman EL, Neugut AI, Grann VRRandomized trial of black cohosh for the treatment of hot flashes among women with a history of breast cancerJ Clin Oncol.(2001 May 15)
- Menopausal Symptoms - Matthias Rostock, Julia Fischer, Andreas Mumm, Ute Stammwitz, Reinhard Saller, Hans Helge BartschBlack cohosh (Cimicifuga racemosa) in tamoxifen-treated breast cancer patients with climacteric complaints - a prospective observational studyGynecol Endocrinol.(2011 Oct)
- Breast Density - E Lundström, A L Hirschberg, G SöderqvistDigitized assessment of mammographic breast density--effects of continuous combined hormone therapy, tibolone and black cohosh compared to placeboMaturitas.(2011 Dec)
- Bone Mineral Density - Michael Bebenek, Wolfgang Kemmler, Simon von Stengel, Klaus Engelke, Willi A KalenderEffect of exercise and Cimicifuga racemosa (CR BNO 1055) on bone mineral density, 10-year coronary heart disease risk, and menopausal complaints: the randomized controlled Training and Cimicifuga racemosa Erlangen (TRACE) studyMenopause.(2010 Jul)
- Blood glucose - Spangler L, Newton KM, Grothaus LC, Reed SD, Ehrlich K, LaCroix AZThe effects of black cohosh therapies on lipids, fibrinogen, glucose and insulinMaturitas.(2007 Jun 20)
- C-Reactive Protein (CRP) - Verhoeven MO, Teerlink T, Kenemans P, Zuijdgeest-van Leeuwen SD, van der Mooren MJEffects of a supplement containing isoflavones and Actaea racemosa L. on asymmetric dimethylarginine, lipids, and C-reactive protein in menopausal womenFertil Steril.(2007 Apr)
- Cognition - Maki PM, Rubin LH, Fornelli D, Drogos L, Banuvar S, Shulman LP, Geller SEEffects of botanicals and combined hormone therapy on cognition in postmenopausal womenMenopause.(2009 Nov-Dec)