Mechanism of action: The two soy isoflavones believed to have phytoestrogenic properties are genistein and daidzein. They appear to work like SERMS (selective estrogen receptor mudulators) and thus are postulated to have positive effects on hot flashes as well as bone turnover and cholesterol profile while acting as an anti-estrogen in the breasts. The half life of the active metabolites of these molecules is about eight hours, which partially explains why some studies have not consistently shown effectiveness of soy products for menopausal symptoms. Daily dosing or studies looking at diets where most of the soy intake is around one main meal have overlooked this important fact.
Mechanism of action: Although red clover contains isoflavones similar to soy, the effectiveness of this herb for menopausal symptoms at relatively small concentrations points to a different mechanism of action. In a study published February of this year it was shown that red clover binds to several types of opiate receptors. These results for the first time suggest a potential new mechanism of action of red clover at the opiate receptors. Given the essential role of the opioid system in regulating temperature, mood, and hormonal levels and actions, this may explain in part the beneficial effect of this herb in alleviating menopausal symptoms.
Mechanism of action: Constituents found in most ginseng species include ginsenosides, polysaccharides, peptides, polyacetylenic alcohols, and fatty acids. Most pharmacological actions are attributed to the ginsenosides that belong to a group of compounds known as steroidal saponins, steroid molecules with attached sugar residues. More than 20 ginsenosides have been isolated. The underlying mechanism of action of the ginsenosides appears to be similar to that for steroid hormones. Actions on virtually every organ system have been described.
Therapeutic effect: Until now, few good quality studies existed on the effect of ginseng for relief of menopausal symptoms; however, hundreds of years of anecdotal evidence exists using ginseng as part of tonics made by Chinese herbalists. Modern literature which has only studied ginseng alone shows a trend towards improved symptoms. In a large double-blinded randomized controlled trial, reduction in hot flashes was not statistically significant but showed a strong trend towards improvement. There was a statistically significant improvement in the depression, well-being and health subscales.
Other areas that show some positive evidence regarding ginseng are:
– improvement in memory
– improvement in immune function
– synergistic effect with opiates in the relief of pain
– optimization of carbohydrate metabolism
Mechanism of action: The exact mechanism by which the triterpenes within black cohosh work to relieve menopausal symptoms is not fully known. It appears that the supplements made of the root and rhizome of the herb act similar to estrogen in the hypothalamus and in bone without causing unwanted effects of endometrial stimulation. While there is some controversy regarding the effectiveness of black cohosh as a single agent, in combination with other herbs black cohosh works to decrease hot flash frequency and severity.
St. John's wort has long been used to treat symptoms of depression. There is ample evidence that this herb is as effective as some popular antidepressants for the relief of mild depression. St. John's wort's efficacy in relieving menopausal symptoms is likely due to two separate actions. First, the herb helps improve the mood changes that are often associated with the hormonal changes of menopause. Second, the herb elevates levels of serotonin in the brain. Gynecologists have long used medications that increase serotonin as an "off-label" treatment to relieve hot flashes. There are excellent scientific studies that support this use. St. John's wort has also been shown to work particularly well in synergy with black cohosh to relieve menopausal symptoms.