What is Black Cohosh?
Botanical Names: Actaea racemosa, Cimicifuga racemosa
Common Names: Black snakeroot, black bugbane, bugwort, rattleroot, rattletop, rattleweed, baneberry
Black cohosh is a perennial flowering plant native to eastern North America, belonging to the buttercup family (Ranunculaceae). The medicinal part used is the root and rhizome (underground stem). The plant grows up to 5 feet tall with white, fragrant flowers arranged in spike-like clusters.
Historical Use: Black cohosh has been used for centuries by Native Americans to treat various ailments including kidney problems, malaria, sore throat, menstrual cramps, childbirth complications, and musculoskeletal pain. European settlers adopted its use, and it became popular in Germany in the late 19th century for women's health issues.
Primary Functions & Benefits
Main Uses:
Menopause Symptom Relief: The most well-researched and primary use
Hormonal Balance: Traditional use for menstrual irregularities
Pain Relief: Historical use for musculoskeletal pain
Women's Health Support: Various gynecological applications
Evidence-Based Benefits:
Menopause Symptoms (STRONGEST EVIDENCE):
Reduction in hot flashes and night sweats (vasomotor symptoms)
Improvement in sleep quality and duration
Reduction in mood disturbances, anxiety, and depression
Relief from psychological symptoms (irritability, nervousness)
Decreased frequency and severity of night sweats
Possible improvement in concentration and fatigue
Other Potential Benefits (LIMITED EVIDENCE):
Bone health support (may have osteoprotective properties)
Menstrual cramp relief
Fertility support when combined with clomiphene citrate (mixed evidence)
Reduction in breast cancer-related hot flashes (unclear effectiveness)
Anti-inflammatory effects
Antioxidant properties
Note on Efficacy:
Research results are mixed. Some studies show significant benefit for menopausal symptoms, while others show minimal improvement over placebo. The most consistent positive results are for vasomotor symptoms (hot flashes and night sweats) and psychological/neurovegetative symptoms.
Mechanism of Action
The exact mechanism by which black cohosh works remains unclear and is subject to ongoing debate. It is NOT a true phytoestrogen, despite common misconceptions.
Current Theories:
Serotonergic Activity: Acts as an agonist at serotonin receptors (5-HT1A, 5-HT7), which may help regulate body temperature and mood
Selective Estrogen Receptor Modulator (SERM): May act selectively on estrogen receptors in some tissues but not others, though this is controversial
Dopaminergic/Noradrenergic Effects: Influences dopamine and norepinephrine neurotransmitter systems
GABAergic Activity: May affect GABA (gamma-aminobutyric acid) pathways
Anti-inflammatory & Antioxidant: Contains compounds that reduce inflammation and oxidative stress
Nitric Oxide Pathway: May affect thermoregulation through nitric oxide mechanisms
Important: Black cohosh does NOT significantly increase estrogen levels, does NOT stimulate endometrial growth, and does NOT contain traditional phytoestrogens found in soy or red clover.
Active Compounds:
Triterpene glycosides (including actein, 23-epi-26-deoxyactein, and cimifugoside): Presumed active ingredients
Phenolic compounds: Including cinnamic acid esters
Salicylic acid: Anti-inflammatory compound (aspirin-like)
Recommended Dosages
Standard Doses:
General use: 20-80 mg daily of standardized extract
Typical dose: 40 mg daily (divided into two 20 mg doses)
Range in studies: 6.5-160 mg daily
Standardization: Should contain 1 mg of triterpene glycosides (27-deoxyactein) per 20 mg tablet
Forms Available:
Capsules/Tablets: Most common; typically 20-40 mg doses
Liquid Extract/Tincture: 2-4 mL, 1-3 times daily (1:1 tincture in 90% alcohol)
Tea: 1/2 to 1 teaspoon of dried root simmered in 1 cup water
Brand Names:
The most studied formulation is Remifemin, which has changed from a 60% ethanol extract to a 40% isopropanol extract.
Duration Recommendations:
Maximum continuous use: 6 months to 1 year
Optimal effect timeframe: 4-8 weeks for full benefits
Not intended for long-term use due to limited safety data beyond one year
Timing & Administration
When to Take:
With or without food: Can be taken either way, though with food may reduce potential stomach upset
Morning or evening: No specific time is superior; take at consistent times daily
Divided doses: If taking 40 mg or more daily, consider splitting into two doses (morning and evening)
Consistency:
Take at the same time(s) each day for best results. Effects may not be noticeable for 4-8 weeks.
Synergistic Supplements & Combinations
May Take WITH Black Cohosh:
Red Clover: Research suggests combining black cohosh and red clover may help manage menopause symptoms more effectively
St. John's Wort: Studies show this combination may benefit menopausal mood symptoms and psychological distress
Soy Isoflavones: Often combined in multi-botanical formulations for menopause
Dong Quai: Traditionally combined for women's health (though evidence is limited)
Vitamin D & Calcium: For bone health support during menopause
Magnesium: May help with sleep and anxiety symptoms
Chasteberry (Vitex): Sometimes combined for hormonal balance
No Strong Evidence for Enhanced Effects:
Most combinations lack rigorous clinical evidence but are theoretically compatible.
Drug Interactions & What NOT to Take
MAJOR INTERACTIONS:
Antidepressants (SSRIs, SNRIs):
CRITICAL: Risk of serotonin toxicity and rhabdomyolysis
Black cohosh has serotonergic properties and may dangerously interact with:
Fluoxetine (Prozac)
Sertraline (Zoloft)
Venlafaxine (Effexor)
Other serotonergic medications
Case reports exist of serious adverse events
Medications Metabolized by CYP450 Enzymes:
Black cohosh inhibits CYP3A4 and CYP2D6 enzymes
May increase levels of drugs metabolized by these enzymes, including:
Statins (rosuvastatin, atorvastatin)
Certain heart medications
Many other prescription drugs
Tamoxifen:
May interfere with tamoxifen's effectiveness
Clinical significance uncertain but concerning for breast cancer patients
Chemotherapy Drugs:
May increase toxicity of doxorubicin and docetaxel
MODERATE INTERACTIONS:
Heart Failure Medications:
ACE inhibitors
Angiotensin receptor blockers (ARBs)
Beta-blockers
Amiodarone
Hormone Therapies:
Estrogen replacement therapy
Birth control pills
Hormone replacement therapy (HRT)
Liver-Toxic Medications:
Nevirapine
Zidovudine
Other hepatotoxic drugs
Aspirin (due to salicylic acid content in black cohosh)
ALCOHOL:
Avoid excessive alcohol use; may increase liver toxicity risk
TOTAL KNOWN INTERACTIONS:
339 drugs have documented interactions with black cohosh
7 major interactions
330 moderate interactions
2 minor interactions
Who Should Take Black Cohosh
Ideal Candidates:
Menopausal & Perimenopausal Women:
Women experiencing hot flashes and night sweats
Those seeking non-hormonal alternatives to HRT
Women with sleep disturbances related to menopause
Those with mood symptoms (anxiety, irritability) during menopause
Women who cannot or prefer not to use hormone therapy
Women with Menstrual Issues:
Menstrual cramps (dysmenorrhea)
Premenstrual syndrome (PMS) symptoms
Irregular cycles (limited evidence)
Women Seeking Natural Alternatives:
Those concerned about risks of hormone replacement therapy
Women preferring herbal/botanical treatments
Those who've experienced adverse effects from HRT
Best Results Seen In:
Postmenopausal women with moderate to severe vasomotor symptoms
Women taking it consistently for 4-12 weeks
Those using standardized, third-party tested products
Who Should AVOID or Use Extreme Caution
ABSOLUTE CONTRAINDICATIONS:
Pregnancy:
Black cohosh may stimulate uterine contractions
Could potentially cause miscarriage or premature labor
NOT safe during pregnancy except under strict medical supervision
Breastfeeding:
Safety unknown; levels in breast milk undetermined
Avoid use while nursing
Liver Disease or Liver Disorders:
Cases of severe liver damage reported (though rare and causality uncertain)
Anyone with hepatitis, cirrhosis, or elevated liver enzymes should avoid
Aspirin Allergy/Sensitivity:
Contains salicylic acid (aspirin-like compound)
Stroke History:
Contraindicated in patients with previous stroke
Uncontrolled High Blood Pressure:
Should be avoided or used only with medical supervision
USE WITH EXTREME CAUTION:
Breast Cancer (Current or History):
Controversial: Some studies suggest safety, others raise concerns
Unclear if black cohosh has estrogenic effects that could stimulate hormone-sensitive cancers
Some retrospective data suggests improved outcomes, but this is not definitive
Always consult oncologist before use
Hormone-Sensitive Cancers:
Endometrial cancer
Ovarian cancer
Uterine fibroids
Endometriosis
Taking Antidepressants:
Serious risk of drug interactions with SSRIs, SNRIs, and other serotonergic medications
Taking Multiple Medications:
High potential for drug-drug interactions
Always review with doctor or pharmacist
Heart Conditions:
One case report of bradycardia (slow heart rate) and complete heart block
Scheduled for Surgery:
May affect blood clotting; discontinue 2-3 weeks before surgery
Potential Negative Effects & Side Effects
Common Side Effects (Generally Mild):
Gastrointestinal issues: Stomach upset, nausea, vomiting
Headaches
Dizziness
Weight gain
Cramping
Vaginal spotting or bleeding
Breast pain or tenderness
Rash or skin reactions
Rare But SERIOUS Side Effects:
Hepatotoxicity (Liver Damage):
At least 83 cases reported globally
Symptoms: Dark urine, yellowing of skin/eyes (jaundice), fatigue, nausea, abdominal pain
Severity ranges from elevated liver enzymes to acute liver failure
Causality uncertain: May be due to product contamination, adulteration, or individual susceptibility
If symptoms develop, STOP immediately and seek medical care
Serotonin Toxicity (when combined with antidepressants):
Agitation, confusion
Rapid heart rate
High blood pressure
Dilated pupils
Muscle rigidity, tremors
Sweating, fever
Medical emergency
Rhabdomyolysis (muscle breakdown):
Muscle pain, weakness
Dark or cola-colored urine
Fatigue
Can cause kidney damage
Cardiovascular:
Bradycardia (slow heart rate)
Complete heart block (rare case report)
Product Quality Concerns:
Some black cohosh products have been found contaminated with other Actaea species or wrong herbs
Adulteration may be responsible for some adverse effects
Always purchase third-party tested products (USP, ConsumerLab, NSF)
Deficiency Symptoms
Not applicable - Black cohosh is not an essential nutrient, so there are no deficiency symptoms. It is a botanical supplement taken for specific therapeutic purposes.
Toxicity Symptoms
Signs of Potential Toxicity/Overdose:
Severe nausea and vomiting
Dizziness and headache
Visual disturbances
Slow heart rate (bradycardia)
Low blood pressure
Tremors
Joint pain
Liver damage symptoms (see above)
Unknown Overdose Threshold:
The exact overdose amount is not well established. To minimize risk:
Do not exceed recommended dosages
Follow product labeling
Do not take multiple black cohosh products simultaneously
Monitor for adverse effects
Important Note:
Black cohosh plant parts (roots, berries) are POISONOUS if consumed raw. Only take in properly prepared supplement form.
Special Considerations
Standardization & Quality:
Major issue: Lack of standardization across products
Triterpene content varies widely between brands
Some products may not contain expected amounts of active ingredients
Solution: Choose products standardized to 2.5% triterpene glycosides or 1 mg of 27-deoxyactein per dose
Third-Party Testing:
Always select products certified by:
USP (United States Pharmacopeia)
ConsumerLab
NSF International
Breast Cancer Considerations:
Conflicting evidence: Some studies show improved disease-free survival; others raise theoretical concerns
Current consensus: Uncertain safety profile in breast cancer patients
Memorial Sloan Kettering Cancer Center notes that patients should consult physicians before use
May interact with tamoxifen
Duration Limitations:
Most studies have lasted 6 months to 1 year
Long-term safety beyond 12 months is unknown
Some experts recommend taking breaks or cycling off after 6 months
Blue Cohosh vs. Black Cohosh:
These are completely different plants:
Blue cohosh (Caulophyllum thalictroides): Different species, different medicinal profile
Blue cohosh is used for different purposes and has different safety concerns
Do not confuse the two
Effectiveness Variables:
Dose matters: Low to moderate doses (20-80 mg) appear more effective than very high doses
Extract type matters: Isopropanolic extracts have more consistent evidence than ethanolic extracts
Individual variation: Some women respond well; others see no benefit
Placebo effect: Menopause symptom relief is highly subject to placebo response
Laboratory Monitoring
Recommended if Using Long-Term:
Liver function tests (ALT, AST, bilirubin) at baseline and periodically
Especially important if taking other medications or with risk factors for liver disease
Discontinue immediately if liver enzymes become elevated
Regulatory Status
United States:
Classified as a dietary supplement
Not FDA-approved for any medical condition
NOT subject to the same rigorous testing as pharmaceutical drugs
Manufacturer claims not evaluated by FDA
Germany:
Approved by German Commission E for menopausal symptoms since 1989
Europe:
Some formulations approved for use up to 6 months for menopause symptoms
Summary & Key Takeaways
Black cohosh is a popular herbal remedy primarily used to alleviate menopausal symptoms, especially hot flashes, night sweats, and mood disturbances. While it has a long history of traditional use and some supporting clinical evidence, research results are mixed, and its exact mechanism of action remains unclear.
Pros:
May reduce hot flashes and night sweats
Non-hormonal alternative to HRT
Generally well-tolerated in short-term use (6-12 months)
May improve sleep and mood in menopausal women
Cons:
Mixed evidence on effectiveness
Rare but serious risk of liver damage
Significant drug interactions (especially with antidepressants)
Not safe during pregnancy or breastfeeding
Uncertain safety in breast cancer patients
Product quality and standardization issues
Bottom Line: Black cohosh may be worth trying for menopausal symptoms under medical supervision, especially if you cannot or do not want to use hormone therapy. However, always:
Consult your healthcare provider first, especially if taking medications
Choose third-party tested products
Monitor for liver symptoms
Limit use to 6-12 months
Stop immediately if adverse effects occur
Not a Phytoestrogen: Despite popular belief, black cohosh does not work through estrogen-like mechanisms and does not contain traditional phytoestrogens.
Medical Supervision Recommended: Given the potential for serious interactions and adverse effects, black cohosh should be used under medical guidance, particularly for women with underlying health conditions or taking prescription medications.