Is it harmful to take black cohosh? Read on and form your own informed opinion. I have my opinion of my own at the end.
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 common names.
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.
Although some study results suggest that black cohosh may help relieve 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, NCCAM is funding a 12-month, randomized, placebo-controlled study to determine whether treatment with black cohosh is effective in reducing the frequency and intensity of menopausal hot flashes. The study will also assess whether black cohosh reduces the frequency of other menopausal symptoms and improves quality of life. The study will examine the possible mechanisms of action of black cohosh.
How black cohosh works is not known. The possibility that black cohosh exhibits estrogenic activity has been studied but the evidence is contradictory.
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. 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.
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.
In the United States, black cohosh is sold as a dietary supplement, and dietary supplements are regulated as foods, not drugs. Manufacturers do not have to provide the Food and Drug Administration (FDA) with evidence that dietary supplements are effective or safe before marketing.
Because dietary supplements are not always tested for manufacturing consistency, the composition may vary considerably from lot to lot.
Can black cohosh be harmful?
Black cohosh can cause stomach discomfort and headaches.
Clinical trials comparing estrogens with black cohosh preparations have shown a low incidence of adverse effects associated with black cohosh; headaches, heaviness in the legs, and weight problems were the main adverse 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.
No studies have been published on long-term safety in humans, particularly regarding abnormal stimulation of Liver damage has been reported in a few individuals using black cohosh, but millions of people have taken the herb without apparent adverse health effects.
While studies of black cohosh have not provided scientific evidence to show that the herb causes liver damage, one country, Canada, 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.
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.
Dosage:
Most studies of black cohosh have used the extract known as Remifemin, which is standardized to contain 1 mg of terpene glycosides per 20-mg tablet.
The most commonly used dosage of Remifemin is two 20-mg tablets twice daily. Maximum effect usually occurs in four to eight weeks.
Recent information from the manufacturer suggests that a dosage of 20 mg twice daily may be as effective in the treatment of menopausal symptoms as 40 mg twice daily.
Black cohosh extract also is available in tincture form; the proper dosage of the tincture is 2 mL twice daily of a 1:1 tincture in 90 percent alcohol.
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.
The majority of the above information is adapted from the National Institute of Health: Office of Dietary Supplements.
Advices for my patients:
• Read about black cohosh and discuss the pros and cons with me.
• Decide whether to take it or not after forming an informed decision.
• Do not exceed the recommended dosage, if he or she decides to use it.
• Avoid taking any brand of supplemnts that contain unknown amount of black cohosh.
I am going through a hard time with my menopause. I have only tried one over the counter drug that has not worked as well as expected. I am now drinking soy milk and looking for a black cohosh supplement. I did see Remifemin at Walmart, next to the Newphase. Is this what I should try?
The Newphase doesn't have the amound of black cohosh listed, but it helps some, more so then without the drugs. I am hoping to find relief soon. At this point in my life I am willing to try anything.. Thanks for the info. I'll be looking for more in the future.
Posted by: Cheryl Yoder | October 14, 2006 at 10:41 PM
Here is a site for the Remifemin that I am now taking (20 days now). Still no relief, hoping soon.
Visit: www.Remifemin.com
Thank you,
Cheryl Yoder
Posted by: Cheryl Yoder | November 26, 2006 at 01:44 PM