The hormonal changes of menopause can produce a wide variety of symptoms, ranging from hot flashes and vaginal dryness to anxiety, depression, and insomnia. Many of these symptoms are undoubtedly caused by the natural decrease in estrogen production that occurs at menopause; however, the human body is so complex that other hormonal factors undoubtedly also play a role.

Menopause is not a disease. It is clearly a natural process, but one that many women prefer not to experience. No longer do women accept as merely part of life the decrease in libido, pain during intercourse, years of hot flashes, and other uncomfortable problems that may accompany menopause. This raises an important point: How close to nature do we want to live? One of the most valued ideals of alternative medicine is the desire to trust nature, but sometimes we may want to draw a line. For example, in a state of nature, infant and maternal mortality is high. This process of survival of the fittest helps humanity as a species to be stronger, but it is not something that a compassionate society can tolerate. Thus, no matter what our ideals, we frequently find ourselves tampering with nature. The treatment of menopause is simply one example among many.

Estrogen-replacement therapy can alleviate many of the problems associated with menopause. However, it creates counterbalancing risks. The most frightening issue is the increased risk of breast cancer that appears to be associated with replacement estrogen. In addition, estrogen therapy can cause blood clots in the legs, and it appears to raise the risk of heart disease rather than prevent it (as previously thought). The decision whether to use estrogen-replacement therapy for menopausal symptoms should involve a careful examination of the risks and benefits in consultation with a physician.

Several natural treatments may reduce menopausal symptoms, as compared to placebo. (The latter comparison is essential, as placebo itself is dramatically effective for menopause, generally reducing the rate of hot flashes by 50%!)28

We do not know for sure whether any of these reduce the risk of osteoporosis. See the full article on Osteoporosis for more detailed information on natural ways to prevent bone loss.

Soy and Soy (or Other Source) Isoflavones

Both soy and red clover contain phytoestrogens (naturally occurring substances with estrogen-like actions) called isoflavones. It is thought that the isoflavones in these herbs may offer some benefits of estrogen with less risk. However, the current evidence base for this hypothesis is conflicting.

Improvements in hot flashes as well as other symptoms, such as vaginal dryness and mood, have been seen in many studies of soy, mixed soy isoflavones, aglycone isoflavones, and the isoflavone genistein alone.23-24,69-72,91-93,146,153,163However, about as many studies have failed to find significant benefit as compared to placebo with soy or concentrated isoflavones.5,43,44,67,73,79,80,94,107,108,113,133-134,153A review of 13 randomized trials with 1,996 women showed a reduced frequency of hot flashes with soy isoflavones compared to placebo, with more than 12 weeks of treatment showing the greatest effect. Hot flash severity improved in 9 randomized trials involving 988 women with soy isoflavones compared to placebo.173

For example, a double-blind study of 247 women suffering from menopausal hot flashes compared the effects of placebo and genistein over a period of one year.133 Genistein was taken at a dose of 54 mg per day. The results indicated that use of genistein significantly reduced hot flashes as compared to placebo.

In addition, isoflavones from red clover have shown inconsistent results in studies, with the best and largest study finding no benefit.68,95,109,110, 114

What can one make of this mixed evidence? One problem here is that placebo treatment has a strong effect on menopausal symptoms. In such circumstances, statistical noise can easily drown out the real benefits of a treatment under study. Unlike estrogen, which has such a powerful effect on hot flashes and other menopausal symptoms that its benefits are almost always clear in studies, soy or concentrated isoflavones likely have a more modest effect, one that does not always show itself above the background noise of statistical variation. It has also been suggested that the placebo used in many of these studies, polyunsaturated fatty acids, may have efficacy of its own; this would tend to hide actual benefits.115

Another explanation may be that certain women benefit from soy isoflavones more than others. In about one-third of people, isoflavones are converted by intestinal bacteria into a substance called equol. At least two studies suggest that these equol producers may experience greater reduction in their menopausal symptoms than non-equol producers.155,156

Evidence regarding whether soy or soy isoflavones are helpful for osteoporosisremains conflicting.7-15,73-75,96-102,159 On balance, it is probably fair to summarize current evidence as indicating that isoflavones (either as soy, genistein, mixed isoflavones, or tofu extract) have a modestly beneficial effect on bone density.

Interestingly, one small but long-term study suggests that progesterone cream (another treatment proposed for use in preventing or treating osteoporosis) may decreasethe bone-sparing effect of soy isoflavones.96

For more information, including dosage and safety issues, see the full Isoflavone article.

Black Cohosh

The herb black cohosh is widely used for treatment of menopause, but the evidence that it works remains incomplete and inconsistent.160,161

The best study was a 12-week, double-blind, placebo-controlled trialof 304 women with menopausal symptoms.111 This study appeared to find that black cohosh was more effective than placebo. The best evidence was for a reduction in hot flashes. However, the statistical procedures used in the study were somewhat unusual and open to question.

Promising results were also seen in a 3-month, double-blind study of 120 menopausal women.141 Participants were given either black cohosh or fluoxetine (Prozac). Over the course of the trial, black cohosh proved more effective than fluoxetine for hot flashes, but fluoxetine was more effective than black cohosh for menopause-related mood changes.

Previous smaller studies have found improvements not only in hot flashes but also in other symptoms of menopause. For example, in a double-blind, placebo-controlled study, 97 menopausal women received black cohosh, estrogen, or placebo for 3 months.81 The results indicated that the herb reduced overall menopausal symptoms (including hot flashes) to the same extent as the drug. In addition, microscopic analysis showed that black cohosh had an estrogen-like effect on the cells of the vagina. This is a positive result because it suggests that black cohosh might reduce vaginal thinning. However, black cohosh did not affect the cells of the uterus in an estrogen-like manner; this too is a positive result, as estrogen’s effects on the uterus are potentially harmful. Finally, the study found hints that black cohosh might help protect bone. However, a great many of the study participants dropped out, making the results less than reliable.

One study, too small to have reliable results from a statistical point of view, found black cohosh equally effective as 0.6 mg daily of conjugated estrogens.125

A study reported in 2006 found that black cohosh has weak estrogen-like effects on vaginal cells and possible positive effects on bone (specifically, stimulating new bone formation).116

A substantial (244-participant) double-blind study published in 2007 compared black cohosh against the synthetic hormone tibolone and found them equally effective for treating menopausal symptoms.142Though not approved as a drug in the US, tibolone does appear to be effective for menopausal symptoms, and therefore these results are somewhat promising.143 However, this study lacked a placebo group, and since the placebo effect is powerful for this condition, this omission significantly reduces the meaningfulness of the results.

One interesting double-blind study evaluated a combination therapy containing black cohosh and St. John's wort in 301 women with general menopausal symptoms as well as depression.117 The results showed that use of the combination treatment was significantly more effective than placebo for both problems. A smaller study using a combination of the same two herbs found improvements in overall menopausal symptoms as well as cholesterolprofile.138

In contrast, there have been several studies that failed to find benefit. For example, in a 12-month double-blind, placebo-controlled study of 350 women, participants were given either black cohosh, a supplement containing 10 herbs, the multibotanical plus soy, standard hormone replacement therapy, or placebo.118,154The results showed significant benefits as compared to placebo for hormone replacement therapy, but only slight, nonsignificant benefits with the other treatments. In addition, a double-blind study of 122 women failed to find statistically significant benefits with black cohosh as compared to placebo,119as did another study enrolling 132 women,123as well as one double-blind, placebo-controlled study that involved 124 women given a black cohosh/soy isoflavone combination.120 These negative outcomes were quite possibly due to the relatively small sizes of the black cohosh groups. In a condition such as menopausal symptoms, where the placebo effect is strong and treatment is relatively weak, large numbers of participants are necessary to show benefit above and beyond the placebo effect. Nonetheless, this is an impressive number of negative studies, and some question must remain about the efficacy of this herb.

The bottom line: Black cohosh may be modestly effective for reducing hot flashes and other symptoms of menopause, but doubts remain.

Some interesting information has developed regarding how black cohosh might work. In the past, the herb was described as a phytoestrogen. However, subsequent evidence indicates that black cohosh is not a general phytoestrogen, but may act like estrogen in only a few parts of the body: the brain (reducing hot flashes), bone (potentially helping to prevent or treat osteoporosis), and possibly the vagina (alleviating dryness and thinning). It does not appear to act like estrogen in the breast or the uterus, which is good news, as estrogen is carcinogenic in those tissues.20,21,30-32,81,83-87,103,121 If this theory is true, black cohosh is a selective-estrogen receptor modifier (SERM), somewhat like the drug raloxifen (Evista). However, more evidence is needed.

For more information, including dosage and safety issues, see the full Black Cohosh article.