Black cohosh is a medicinal plant native from eastern North America. Known for its anti-inflammatory, sedative, and pain-relieving properties, black cohosh has the potential to relieve menopausal symptoms and support reproductive health. However, clinical research is limited and far from conclusive. Keep reading to discover the benefits and side effects of black cohosh.
What is Black Cohosh?
Scientific name: Actaea racemosa/Cimicifuga racemosa
Common names: Baneberry, black cohosh, black snakeroot, bugbane, cimicifuga, rattleroot, rattleweed, rattletop, traubensilberberze, squawroot, and wanzenkraut.
Actaea racemosa, also known as black cohosh, is a medicinal plant from the Ranunculaceae family, and native from Eastern North America. Before the arrival of the Europeans, Native Americans used black cohosh to relieve various disorders including several conditions unique to women such as menopause and amenorrhea [1, 2].
Black cohosh became an official drug in the United States Pharmacopeia in 1820. Yet, black cohosh grew in popularity in 1844 when Dr. John King, an eclectic physician, published its use as a treatment for a variety of conditions including chronical ovaritis, endometriosis, and menstrual derangements [1].
Today, black cohosh is still used to treat several disorders like anxiety and menopausal symptoms. However, there is an ongoing debate on the efficiency of black cohosh to treat these conditions [3].
Snapshot
Proponents:
- Relieves menopausal symptoms
- Supports female fertility and reproductive health
- Might help with diabetes and anxiety
Skeptics:
- All benefits lack solid clinical evidence
- May damage the liver
- May interact with different medications
- Not safe for pregnant women
Components
The key medical components in black cohosh include triterpene glycosides, phenolic acids, flavonoids, volatile oils, and tannins.
Triterpene Glycosides
- Actein is found in the roots of black cohosh and can inhibit the growth of breast tumors [4].
- 23-epi-26-deoxyactein is similar to actein, and this compound is a triterpene glycoside that can be extracted from black cohosh roots [5].
- Cimicifugosidase is obtained from black cohosh roots and also has anticancer effects [6].
Polyphenolic Acids
Currently, more than 20 polyphenolic derivatives have been found in the roots of black cohosh, including caffeic acid, isoferulic acid, fukinolic acid, and cimicifugic acids. These compounds have anti-inflammatory and antioxidant properties [7, 8].
Volatile Oils
Also known as essential oils, volatile oils are insoluble in water and come from a variety of plants. Volatile oils may be helpful in the prevention and treatment of different chronic conditions [9].
Tannins
Tannins are polyphenolic compounds present in many plant foods. They have anti-cancer, antioxidant, and antimicrobial properties [10].
Mechanism of Action
Although several clinical studies have shown the effectiveness of black cohosh extract in treating menopausal symptoms, its mechanism of action is still unknown [11].
One proposition states that black cohosh extract may act as a selective estrogen receptor modulator, meaning that it may “simulate” the normal activity of estrogen. Yet, several studies have shown that black cohosh extract does not have any estrogenic effects [12, 13].
Another theory proposes that the effects of black cohosh derive from its antioxidant properties. However, a study on fish did not detect antioxidant properties from black cohosh [14].
A more accepted theory states that a serotonin derivative (Nw-methylserotonin) found in black cohosh may activate serotonin receptors [15, 16].
Health Benefits of Black Cohosh
Possibly Effective:
1) Menopausal Symptoms
In one study of 84 postmenopausal women, black cohosh tablets decreased hot flashes, compared to placebo [17].
In another study, 48 postmenopausal women with sleep disturbances received a daily dose of either black cohosh or placebo during a 6-month period. The results showed that, compared to placebo, black cohosh improved the sleep quality of postmenopausal women [18].
A specific standardized product made of back cohosh (Remifemin) successfully reduced hot flushes and other menopausal symptoms in multiple clinical trials [19, 20, 21].
However, a meta-analysis reviewed 16 different studies to test the effectiveness of black cohosh for treating menopausal symptoms. The main conclusion of the study was that there was insufficient evidence to prove that black cohosh is an effective alternative to treat menopausal symptoms [22].
The authors remarked the overall poor quality of the studies and warranted further research. Many studies showed incomplete data outcomes, poor reporting, statistical insignificance, and vague conclusions.
2) Fertility
In one study of 119 infertile women, adding black cohosh to clomiphene citrate improved pregnancy rate [23].
A systematic review involving 33 studies analyzed the effect of 6 plants including black cohosh on women with PCOS. In this review, it was concluded that black cohosh may increase ovulation and improve fertility [24].
3) Uterine Fibroids
A uterine fibroid is a non-cancerous tumor in the uterus. In a study of 244 patients, black cohosh extract was more effective against uterine fibroids than a drug tibolone [25].
Animal and Cellular Research (Lacking Evidence)
No clinical evidence supports the use of black cohosh for any of the conditions listed in this section. Below is a summary of the existing animal and cell-based studies; they should guide further investigational efforts but should not be interpreted as supportive of any health benefit.
Diabetes
In an animal study, black cohosh extract was administered orally and by injection to mice over a span of 7 days, which resulted in significant blood glucose reduction [26].
Bone Strength
Black cohosh extract was administered intravenously to rats in different doses, which resulted in reduced bone mass loss [27].
HIV
In a cell-based study, 83 chemicals from different plants were evaluated for anti-HIV activity. Of these chemicals, actein (a key component of black cohosh extract) elicited a strong response against HIV [28].
Anxiety
Black cohosh extract reduced anxiety-related behavior in mice by promoting a state of sleepiness [29].
Black Cohosh Side Effects & Precautions
Black cohosh is possibly safe when taken in adequate amounts, up to six months. Mild side effects linked to black cohosh use include [30]:
- Upset stomach
- Rash
- Headache
- Dizziness
- Breast pain
Caution is warranted due to its potential to cause the following more serious side effects:
1) Liver Damage
A 44-year old woman that used black cohosh for a month developed liver damage. Since the woman was not taking any other drugs, it was concluded that liver injury was caused by the use of black cohosh [31].
There have been other reports of liver damage in people who used this herb, but the exact underlying cause was not clear in most cases [31, 32, 33, 34].
2) Breast Cancer Worsening
In one study, mice with breast cancer received 0.3 mg/day of black cohosh extract. The results of the experiment showed that black cohosh increased the spread of cancer cells (metastasis) from existing tumors [35].
Pregnant women should avoid black cohosh due to its potential to impact reproductive hormones and stimulate the uterus [36].
Drug Interactions
- Tamoxifen (Nolvadex): A cell-based study showed that using black cohosh and tamoxifen at the same time might reduce the effectiveness of this drug [37].
- Atorvastatin (Lipitor): A case study of a 53-year-old woman taking black cohosh and atorvastatin simultaneously found that the combination resulted in a dangerous increase in liver enzymes that may indicate liver damage [38].
- Chemotherapy: In a cell-based study, the interaction between black cohosh and common drugs used in cancer therapy was tested. The results showed that black cohosh increased the toxicity of doxorubicin (Adriamycin) and docetaxel (Taxotere) on cancer cells. However, black cohosh also decreased the efficiency of cisplatin on cancer cells [39].
- Drugs metabolized by the liver: Black cohosh reduces the activity of cytochrome P450 (CYP450) enzymes, which break down several drugs. The inhibition of these enzymes may lead to liver damage [40, 41].
Supplementation
Black cohosh supplements have not been approved by the FDA for medical use. In general, regulatory bodies aren’t assuring the quality, safety, and efficacy of supplements. Speak with your doctor before supplementing.
Forms
The most common method of taking black cohosh is by tablets. However, black cohosh is also available in capsules, liquid tinctures, and extracts that can be mixed in water and dried root for tea [42].
Dosage
The below doses may not apply to you personally. If your doctor suggests using balck cohosh, work with them to find the optimal dosage according to your health condition and other factors.
There is no standardized dose for the use of black cohosh, but a dose of 40 mg/day is commonly used in studies for a variable period of time, depending on the metabolism of the patient and the severity of the symptoms [43].
In several studies, women have used black cohosh at a dose of 160 mg/day without any visible side effects [43].
