Reproductive or Thyroid Hormones and Menstrual Cycle Not Influenced by S-equol Supplement Designed to Manage Menopause Symptoms

Apr 04, 2014, 09:00 ET from Pharmavite LLC

NORTHRIDGE, Calif., April 4, 2014 /PRNewswire-USNewswire/ -- A daily dose of S-equol (13.1 mg), delivered via a fermented soy germ-based nutritional supplement to manage menopause symptoms, showed no impact on reproductive or thyroid hormones or the menstrual cycles of premenopausal women, according to a peer-reviewed study reported in a poster at the Academy of Women's Health 2014 annual meeting in Washington, DC.

Previous controlled clinical trials documented that daily doses of the supplement containing S-equol, a metabolite of the soy isoflavone daidzein, relieved menopausal symptoms, specifically hot flash frequency and muscle discomfort, in both U.S. and Japanese postmenopausal women.

"These data demonstrate that in premenopausal women, use of this supplement does not impact levels of specific endocrine hormones. Furthermore, the S-equol supplement does not impact menstrual cycles of premenopausal women which helps to confirm and expand what we know about safety of the S-equol supplement from previous studies," said coauthor Belinda H. Jenks, Ph.D., Director of Scientific Affairs & Nutrition Education at Pharmavite LLC, the makers of Nature Made® vitamins and minerals and a subsidiary of Otsuka Pharmaceutical Co., Ltd., which supported the study.

S-equol has the ability to bind to the same estrogen receptors as naturally occurring estrogen, with a strong affinity to the estrogen receptor beta. On binding to the receptor, S-equol mimics some, but not all, activities of estrogen. Because of these actions at the receptor, it has been proposed that S-equol may alleviate some menopause symptoms caused by diminished estrogen production.

No Impact from S-equol Supplements on Reproductive or Thyroid Hormone Levels and Menstrual Cycle in Premenopausal Women
During the treatment period and post-treatment period, each of which was lasted for one menstrual cycle in each subject, a dose of a supplement containing 13.1 milligrams (mg) S-equol daily did not significantly alter the levels of five reproductive and three thyroid hormones from pre-treatment values, which remained within the normal range and did not differ from levels in women receiving a placebo in a study of 35 Japanese women aged 20 to 38 years. Moreover, neither the supplement nor the placebo affected the length of the women's menstrual cycles, which averaged 28.4 to 30.0 days, p=0.430 for the difference between groups and p=0.921 for the differences in the three cycle phase measures.

Specifically, the women receiving the supplement did not differ from the 18 women receiving the placebo in delta changes of the levels of luteinizing hormone (treatment minus pre-treatment: p=0.260 and post-treatment minus pre-treatment: p=0.486), follicle stimulating hormone (p=0.322 and p=0.456), estradiol (p=0.712 and p=0.703), progesterone (p=0.085 and p=0.462) and testosterone (p=0.720 and p=0.764).  Additionally, the two groups did not differ in measures for levels of thyroid stimulating hormone (p=0.082 and p=0.111), free T3 (a form of triiodothyronine) (p=0.197 and p=0.416) and free T4 (a form of thyroxine), (p=0.223 and p=0.724).

Investigators took blood samples from each woman during the early follicular phase, about three to five days after onset of the period, the late follicular phase, about 10 to 13 days after onset of the period, and the luteal phase, about seven to 10 days after ovulation. The investigators repeated these blood samples during the course of three sequential cycles. During the first and last cycles, the women did not take any treatment, while during the middle cycle; the women received either the supplement or a placebo based on random assignment to a treatment group.  This treatment lasted approximately four weeks, depending on the duration of the women's individual cycles.

Only women who had regular menstrual cycles, 28 to 35 days, were accepted and enrolled and of these, 12 were natural equol producers after soy consumption. All of the women self-checked their ovulation cycles using commercial urine tests.

The complete data will be submitted to a peer-review journal for publication.

About Equol
S-equol is a compound resulting from the natural metabolism, or conversion, of daidzein, an isoflavone found in whole soybeans. Not everyone can produce S-equol after soy consumption, as the production depends on the types of bacteria present in the large intestine. About 50 percent of Asians and 20 to 30 percent of North Americans and Europeans, who in general consume less soy than Asians, have the ability to produce equol.

The safety of the supplement containing S-equol previously was confirmed by standard animal testing breast cancer model, including a study documenting that S-equol itself, as well as the supplement containing S-equol, did not increase or stimulate the growth of breast cancer cells. Studies involving postmenopausal women who consumed the supplement containing S-equol have not observed any safety problems, including analysis of breast and reproductive tissues and of hormone levels.

Development and ongoing research of a supplement containing S-equol is conducted by the Saga Nutraceuticals Research Institute of Otsuka Pharmaceutical Co., Ltd. Pharmavite LLC, a subsidiary of Otsuka, is studying the supplement containing S-equol for the management of menopausal symptoms.

More information about S-equol, including results of studies, is at

How the S-equol Supplement is Made
The supplement is the product of fermentation of whole soy germ by the bacterial strain Lactococcus 20-92 using a patented and proprietary process by the Otsuka Pharmaceutical Co., Ltd. The process results in the conversion of the soy isoflavone daidzein to S-equol. The S-equol ingredient is created under current Good Manufacturing Practices. Following fermentation, the bacteria undergo heat denaturation and are deactivated. The process is designed to produce an S-equol rich product, or nutraceutical ingredient. The ingredient has self-affirmed GRAS (Generally Recognized As Safe) status.

Academy of Women's Health Poster, to be presented Saturday, April 5, 5:15-6:45 pm ET
S-equol supplementation does not impact reproductive or thyroid hormone levels and menstrual cycle in premenopausal women.

Soh Iwashita, PhD of Otsuka Pharmaceuticals Co., Ltd. and Pharmavite LL; Belinda H. Jenks, Ph.D., Pharmavite LLC; Tomomi Ueno, MS, Atsuko Onoda, M.S., and Shigeto Uchiyama, MS, all of Otsuka Pharmaceuticals Co., Ltd.; and Takeshi Aso, M.D., Ph.D., Professor and Chairman Emeritus, Department of Comprehensive Reproductive Medicine at the Tokyo Medical and Dental University and President-Elect of the Asia Pacific Menopause Federation.

About Pharmavite LLC:
For more than 40 years, Pharmavite LLC has earned and maintained the trust of healthcare professionals, consumers, and retailers by manufacturing high-quality vitamins, minerals and other dietary supplements, and all-natural foods under its Nature Made® and SOYJOY® brand names. Based in Northridge, California, Pharmavite LLC operates as a subsidiary of Otsuka Pharmaceutical Co., Ltd.  For more information, please visit

About Otsuka Pharmaceutical Co., Ltd.:
Founded in 1964, Otsuka Pharmaceutical Co., Ltd. is a global healthcare company with the corporate philosophy: 'Otsuka-people creating new products for better health worldwide.' Otsuka researches, develops, manufactures and markets innovative and original products, with a focus on pharmaceutical products for the treatment of diseases and consumer products for the maintenance of everyday health. Otsuka is committed to being a corporation that creates global value, adhering to the high ethical standards required of a company involved in human health and life, maintaining a dynamic corporate culture, and working in harmony with local communities and the natural environment. Otsuka Pharmaceutical Co., Ltd. is a wholly owned subsidiary of Otsuka Holdings Co., Ltd., the holding company for the Otsuka Group. The Otsuka Group has business operations in 25 countries and regions around the world, with consolidated sales of approximately USD 13 billion for fiscal year 2012 (4/1/2012-3/31/2013.)  Visit Otsuka Pharmaceutical Co., Ltd. at

SOURCE Pharmavite LLC