Product Reviews
Menopause Supplements Review (Soy and Red Clover Isoflavones, Black Cohosh) and Progesterone Creams

Reviewed and edited by Tod Cooperman, M.D. Tod Cooperman, M.D.
Initial Posting: 7/24/15 Last Update: 3/6/19
Menopause Supplements Tested by -- Soy and Red Clover Isoflavones, Black Cohosh, and Progesterone Cream
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  • Soy isoflavones have a mild estrogenic effect and can modestly reduce menopausal symptoms, such as hot flashes. Products providing at least 50 mg of soy isoflavones daily or of specific soy isoflavones (15 mg of genistein or 28 mg of daidzein) may be important for these effects and require treatment for several weeks before experiencing improvement. Higher doses are typically used to help maintain bone density (see Soy Isoflavones -- What It Does).
  • Product labeling typically does not provide details about the specific forms of isoflavones, but ConsumerLab determined these from testing, You can check amounts of isoflavones in products by looking at the 4th column of the Results Table below -- amounts known to be effective are in bold.
  • Be aware that only about 1/3 to ½ of women may benefit from isoflavones, depending on whether or not they convert isoflavones into active forms in their gut (See Soy Isoflavones - What It Is).
  • Red clover isoflavones may also have benefit in menopause, particularly in reducing night sweats, but it is recommended that products provide at least 40 mg daily of total isoflavones. Both products tested in this review provided this amount or more (See What CL Found).
  • Black cohosh, unlike soy isoflavones, does not have general estrogen-like actions, but may act like estrogen only in certain places, such as in the brain and the vaginal epithelium, providing no or modest benefit for symptoms such as hot flashes and vaginal dryness (See Black Cohosh —What It Does). The frequently recommended dosage of black cohosh is 20 mg of standardized extract once or twice a day, manufactured to contain at least 1 mg of triterpenes per day, although some products provide much larger amounts (See the 2nd and 4th columns in the Results Table below) and some products, like Remifemin, may work despite containing no triterpenes.
  • Progesterone cream may decrease menopausal hot flashes but does not provide enough progesterone to prevent bone loss or improve bone density (See Progesterone —What It Does). The progesterone creams tested by ConsumerLab were found to contain the amounts of progesterone they claimed. (See Progesterone Results Table).
Changing hormone levels around the time of menopause can trigger many symptoms in women, including hot flashes, flushing, vaginal dryness, and a fading sex drive. Such problems are often temporary, but some women suffer for several years or more. Hormone replacement therapy may ease these symptoms but carries potential health risks. Popular alternative treatments include phytoestrogens (from soy, red clover and kudzu), black cohosh, and progesterone creams.

But what are women really getting from these non-prescription menopause remedies? tested a wide range of products to see what they really contain, with some often surprising results. Our report also includes expert advice on selecting and using menopause products to get the most benefits with the fewest risks.

Menopause typically occurs between the ages of 50 and 52 (McKnight, Am J Obstet Gynecol 2012) although this can vary based on a number of factors, including genetic differences and family history, ethnicity, and lifestyle factors such as weight, smoking status and physical activity. Observational studies suggest that earlier-onset menopause may be associated with an increased risk of lower bone density, osteoporosis, depression, cardiovascular disease and premature death, while late-onset menopause may be associated with a higher risk for breast, ovarian and endometrial cancers (Gold, Obstet Gynecol Clin North Am 2012).

Diet may also influence the age at which menopause occurs. A study that followed 1,874 British women between the ages of 40 and 65 for four years found that high intakes of oily fish and fresh legumes, and higher intakes of vitamin B6 and zinc were associated with a delayed onset of menopause, while consumption of refined pasta and rice was associated with an earlier onset. The study found that consumption of 3.5 oz. of oily fish per day and 2.5 oz of fresh legumes (i.e. green beans, peas, edamame, fresh lima beans etc.) was associated, respectively, with an approximate 3-year, and 1-year delay in the onset of menopause, while the consumption of 7 oz. of refined pasta or rice per day was associated with a 1.5 year earlier onset of menopause (Dunneram, J Epidemiol Community Health 2018).

Soy and Red Clover Isoflavones:

What It Is:
Phytoestrogens are estrogen-like plant compounds, although they are considerably weaker than estrogen itself. The most well-studied phytoestrogens are the isoflavones, particularly those found in soy (Glycine max) and red clover (Trifolium pratense).

If a woman is already making estrogen on her own, isoflavones can actually block the hormone by taking up spots in the body's estrogen receptors. This may help explain why women who eat a lot of soy early in life seem to have a lower risk of breast cancer. It's also why isoflavones can help ease cyclical mastalgia (breast pain associated with the menstrual cycle).

In nature, most isoflavones (about 95%) are attached to sugar molecules (glycosides). Most manufacturers include the weight of the sugar in the stated amount of isoflavones. In such products, as much as 40% to 50% of the claimed "total isoflavones" may really be sugar. A more precise label should state just the weight of the active part of the isoflavones, excluding the sugar portion of the molecule. These are called "aglycone" (meaning "without sugar") isoflavones. They may also be referred to by their specific names. For soy, the aglycone isoflavones are genistein, daidzein, and glycitein. The glycosidic (with sugar) forms are genistin, daidzin and glycitin. These are also found in red clover and kudzu. Red clover also includes the glycosidic isoflavones biochanin A and formononetin, while kudzu contains the glycosidic isoflavone puerarin.

When consumed, the sugar molecules of glycosidic isoflavones are removed in the intestine by bacterial enzymes and the remainder is converted to the metabolically active aglycone forms. After this conversion, approximately one-third of aglycones are absorbed as free isoflavones, and bacteria convert the other two-thirds to isoflavone metabolites such as equol and p-ethylphenol, which also get absorbed into the bloodstream.

Importantly, not all women handle isoflavones the same way. For example, some do not have the specific gut bacteria necessary to convert glycosidic isoflavones into aglycones and only about one-third to one-half of women convert isoflavones to equol. Some, but not all, evidence suggests that equol-producing women may enjoy far more benefits from isoflavones, including reduction of menopause symptoms (Jou, Int J Gyn Obst 2008).

What It Does:
Seal of Approval Much of the clinical and epidemiological research regarding isoflavones was originally based on intake of soy-based foods. Soy contains a variety of isoflavones and many other biologically active compounds, so it is difficult to know which health effects are attributable to which compounds. More recent studies have focused on products containing defined amounts of isoflavones.

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