What the Research Says About Soy Safety

What the Research Says About Soy Safety

While EQUELLE only contains trace amounts of soy, we believe it’s necessary to talk openly about this little legume and its somewhat sticky reputation. Here’s what over 20 years of research has to say on the safety of soy, and why we’re confident EQUELLE delivers safe, consistent, menopausal symptom relief.

Is soy safe?

Yes. A consistent body of research in humans over the last twenty years confirms that consuming certain amounts of soy is safe and has not been shown to lead to breast cancer or other cancers. But don’t just take our word for it. Here’s what some of the leading health organizations have to say about the safety of soy as well:

“So far, the evidence does not point to any dangers from eating soy in people.”

  • - American Cancer Society1

“A consistent body of research shows soy foods are safe for those diagnosed with cancer and those without.”

  • - American Institute for Cancer Research2

“Except for people with soy allergies, soy is believed to be safe when consumed in normal dietary amounts.”

  • - US National Center for Complementary & Integrative Health3

“Food sources of soy don’t contain high enough levels of isoflavones to increase risk for breast cancer.”

  • - Mayo Clinic4

Why is there so much fear around soy?

Because in the early 1990s, some early research in animals led many people to believe soy could have a negative effect on humans.2 Despite that this research was not in humans, it led to a surge in media coverage regarding the safety of soy in humans.

Since the late 1990s, however, human studies have continued to show that soy is safe for people when consumed in normal dietary quantities—including those suffering from cancer or thyroid disorders.5-6 While people in other countries, like Japan, have taken to soy for its many potential health benefits, there’s still a lingering fear of this legume in the United States. It may take decades to undo, but we believe the best course of action is to educate ourselves and our families surrounding soy and then hope each woman decides for herself.

How much soy is in Equelle?

While our key ingredient, S-equol, is a naturally derived compound of soy isoflavone daidzein—each daily serving of EQUELLE contains only a trace amount of soy isoflavones. This is significantly less than the amounts of isoflavones present in a single serving of other soy foods. For example, ½ cup of miso contains 17.5 times more isoflavones than one daily serving of EQUELLE.

infographic measure soy isofavones


Isoflavones are also known as “phytoestrogens” and those have a whole set of safety data as well. An analysis of over 150 studies shows phytoestrogen supplements have a safe side effect profile with only a slight risk for mild gastrointestinal effects.7 Our clinical findings show no increase in breast density or endometrial thickness following daily supplementation of S-equol at 10 or 30 mg over 12 weeks.8

Where does the soy in Equelle come from?

Our key ingredient, S-equol, is made from a specific soy isoflavone. Isoflavones are often used in menopause supplements due to their abilities to “mimic” estrogen within the body without raising estrogen levels. As women, we have estrogen receptors all over our bodies which means that a loss of this vital hormone can be felt throughout our bodies as well. S-equol helps fill this role in the absence of estrogen and works to help alleviate some of our most common menopause symptoms.

But S-equol isn’t easy to make. Everyone’s gut bacteria are different. Only some women have certain bacteria that allow them to make S-equol after consuming soy. Our patented fermentation process mimics these specific gut conditions. We extract a small amount of soy germ from the bean, which—when added to our specialized fermentation process—produces a stabilized and concentrated amount of S-equol. We then use this S-equol in EQUELLE.

fermentation soy germ s-equol

This is how EQUELLE delivers consistent, safe, and effective multi-symptom menopause relief in every serving.

What should I do if I'm still concerned about soy?

We know soy is a sensitive subject for many women. We wanted to share some research with you about why we’re confident that our product remains safe and effective. Of course, ultimately this decision is wholly your own.

All of us should examine our own needs, desires, risks, and benefits for ourselves before deciding how to manage our menopause symptoms. If we’re suffering at all, we can’t give up until we find a solution. But what those answers are will be different for everyone.

If you have a soy allergy, EQUELLE may not be right for you. We recommend consulting your healthcare practitioner before introducing any new supplements to your diet.

Want to ask your doctor about S-equol? Bring our “Efficacy of S-equol for Menopausal Symptom Relief” handout with you to your next visit.



  1. American Cancer Society – Simon, S. “Soy and Cancer Risk: Our Expert’s Advice.” 2019. Accessed on: October 25, 2019. <https://www.cancer.org/latest-news/soy-and-cancer-risk-our-experts-advice.html>
  2. American Institute for Cancer Research. “Soy and Cancer Survivorship.” 2019. Accessed on October 25, 2019. <https://www.aicr.org/patients-survivors/healthy-or-harmful/soy.html>
  3. National Center for Complementary and Integrative Health. “Soy.” 2016. Accessed on October 25, 2019. <https://nccih.nih.gov/health/soy/ataglance.htm>
  4. Mayo Clinic – Zeratsky, K. “Healthy Lifestyle Nutrition and Healthy Eating – Will eating soy increase my risk of breast cancer?” 2018. Accessed on October 25, 2019. <https://www.mayoclinic.org/healthy-lifestyle/nutrition-and-healthy-eating/expert-answers/soy-breast-cancer-risk/faq-20120377>
  5. Zhang, FF et al. “Dietary isoflavone intake and all-cause mortality in breast cancer survivors: The Breast Cancer Family Registry.” Cancer. 2017; 123(11):2070-79.
  6. Otun, J et al. “Systematic Review and Meta-analysis on the Effect of Soy on Thyroid Function.” Sci Rep. 2019; 9(1):3964.
  7. Tempfer, CB et al. “Side Effects of Phytoestrogens: A Meta-analysis of Randomized Trials.” Am J Med. 2009; 122(10):939-46.
  8. Oyama, A et al. “The effects of natural S-equol supplementation on skin aging in postmenopausal women: a pilot randomized placebo-control trial.” Menopause. 2012; 19(2):202-210.