Wednesday Bubble: Is S-equol the next big thing?

Posted by on Jul 14, 2010 in new approaches | 5 comments

Last year I wrote a few posts about the potential of the isoflavone S-equol for addressing menopausal symptoms, including hot flashes and mood swings.

If you are unfamiliar with S-equol, it is actually a metabolite of a one of the three soy isoflavone compounds (i.e. daidzein), and is produced by bacteria that live in the intestines. One of the most interesting things about S-equol is that is one of the principal types of isoflavones that are found in soybeans and most soy foods. However, up to 80% of the U.S. population and about half of the Japanese population (who consume inordinate amounts of soy) cannot manufacture S-equol on their own and need to obtain it in supplement form.

This month’s Journal of Nutrition has devoted an entire supplement to S-equol research, and I’ve been fortunate to take a more detailed look at the evidence supporting the role of S-equol for menopausal symptoms. Notably, some of the  researchers actually say that “to conduct menopausal medical care appropriately [which, in their opinion, should be geared towards a better quality of life on an individual basis), it is necessary to provide evidence-based alternative medicines as much as possible.” It is wonderfully refreshing to find such esteemed colleagues backing my view of how menopause should be approached.

Hence, without further ado, following is what you need to know about the recap of study findings, and what still needs to be explored before we all start taking S-Equol.

In three randomized studies conducted in pre-, peri- and menopausal Japanese women who were or were not able to produce S-equol naturally, researchers found specific benefits in three areas:

  • Mood improvement: 134 women who produced S-equol naturally and took a 10 mg daily S-equol supplement had significant reductions in anxiety; those who took 10 mg three times a day had significant declines in tension-anxiety and fatigue, and an increase in overall energy. Note that these women also limited their daily intake of soy products to no more than 20 mg/day.
  • Hot flashes and other symptoms: In 320 women taking 10 mg S-equol daily or placebo for 12 weeks, S-equol supplements reduced the frequency of hot flashes by as much as 58%. Decreases in muscle and neck stiffness were also reported.
  • Bone health: In 54 women who had undergone menopause within 5 years of the study, those who were able to produce S-equol naturally and took 75 mg  isoflavones daily supplement (mostly consisting of daidzein) lost a significantly lower percentage of bone in their hip area than women who were not able to produce S-equol naturally but also took the daily supplement. Researchers believe that S-equol actually mimics the action of estrogen in the body in terms of its ability to maintain bone mass and the balance between the build up of bone (bone formation) and the loss of bone (bone resorption). However, studies looking at how it acts in the body have only been conducted in mice and at relatively high doses. Information reported in the Journal supplement does show that at higher dosages, S-equol can negatively affect the tissues lining the uterus.

A few key take-away points to think about when we think about S-equol:

Researchers believe that the research in S-equol helps to show that soy isoflavones work best in individuals whose bodies are able to produce S-equol naturally. However, you’ve read the stats – the majority of people who live in the US do not produce S-equol naturally. Dosing and the exact type of S-equol may also influence outcomes. Likewise, They still aren’t sure how bacteria in the intestines influence S-equol’s effects and wonder if somehow, some other mechanism is at play. Further research is also needed to see if the beneficial effects of S-equol on menopausal symptoms can be extended to women who do not produce it naturally.

It’s too early to boost this bubble and I’m excited by this evidence-based alternative. Naysayers love to point out that alternative therapies are sham and snake oil. While this may be true of some preparations, it’s clear that researchers are taking natural substances to a higher level to see if they offer efficacy without the risks of hormone replacement.


  1. 8-2-2010

    Is it available in the UK for sale?
    I have a friend who needs the product.

    • 8-2-2010

      So far as I know, this is stil in research phase and there aren’t any products available.

  2. 12-3-2010

    I am in the process of going in a trial for s-equol. Can anyone who has been on the trial tell me if they found it worthwhile and safe. What side effects were experienced?

  3. 1-26-2011

    “Natural S-equol decreases bone resorption in postmenopausal, non-equol-producing Japanese women: a pilot randomized, placebo-controlled trial,” Tousen Y, Ishimi Y, et al, Menopause, 2011, Jan 19; [Epub ahead of print]. (Address: Division of Human Nutrition and Applied Physiology, Chiba Prefectural University of Health Sciences, Chiba, Japan).
    In a double-blind, randomized, placebo-controlled study involving 93 non-equol producing Japanese women, results indicate that supplementation with equol may improve bone health. The women were randomized to one of four groups for 12 months: 1) received placebo; 2) received 2 mg of equol; 3) received 6 mg of equol; 4) received 10 mg of equol. At intervention end, women in the the 10 mg equol group showed a 23.94% decrease in urinary deoxypyridinoline, thereby showing inhibition of bone resorption. Additionally, there was no decrease in bone mineral density in the 10 mg equol group. Thus, the authors of this study conclude, “These findings suggest that 10 mg/day of natural S-equol supplementation contributes to bone health in non-equol-producing postmenopausal women without adverse effects.”

    • 1-26-2011

      Thanks for the heads up on the new study! Cheers!


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