Otsuka Pharmaceutical Co., Ltd. (Otsuka) has women's health as one of its focus areas, including the unique challenges women face throughout different life stages. To support this, we are actively engaged in both research and awareness-raising initiatives.

In a recent study published in the Journal of the Japan Society for Menopause and Women's Health, we examined skin changes associated with the menstrual cycle. Our findings categorized these changes by severity and suggested that a jelly drink containing equol, vitamin D, collagen, calcium, and magnesium (the "test food") may help improve skin condition following menstruation.

■ Our Findings

• Subjective skin evaluations showed that, without the test food, participants experienced improved overall skin conditions from Day 6 to Day 13 of the menstrual cycle. However, these improvements were reduced by the onset of the next cycle.

• In contrast, when the test food was consumed for six days following menstruation, the skin score from day 6 to day 13 showed a significant enhancement compared to the non-intake period. In addition, the consumption of the test food suppressed the deterioration of skin scores at the beginning of the next menstrual period (Figure 1). Objective assessments further supported this effect, with significant improvements observed in skin smoothness scores from Day 6 to Day 13 (Figure 2). These results indicate that the test food may contribute to better post-menstrual skin condition.

• Additionally, six days of test food consumption led to an increase in serum 25(OH)D₃, the storage form of vitamin D, which remained elevated for one week after discontinuation. This is the first study to evaluate the effects of a short-term (six-day) intervention using a low dose (20 µg) of vitamin D₃ in Japanese women.

■ Summary:

This study investigated the impact of menstrual cycle-related hormonal fluctuations on skin conditions and the potential benefits of foods containing equol, vitamin D, collagen, calcium, and magnesium. A non-blind crossover trial was conducted with 109 premenopausal women who reported experiencing changes in their skin conditions throughout their menstrual cycles. The first day of menstruation was considered Day 1, the participants consumed the test food for 6 consecutive days starting Day 7 during the test food intake period. The skin condition was evaluated subjectively with a self-administered questionnaire and objectively with a physiological assessment. The results demonstrated a significant improvement in the skin condition from Days 6 to 13 during the non-intake period. Conversely, significant deterioration was observed from Day 6 to the beginning of the next menstruation period. During the test food intake period, significant improvements were observed in several areas, including skin roughness. Moreover, these improvements were more pronounced in equol non-producers. This suggests that the consumption of the test food post-menstruation can potentially enhance the skin condition and suppress the deterioration typically experienced at the beginning of the next menstruation cycle.

■ About Equol

Equol is a metabolite of soy isoflavone daidzen, which is produced through the action of intestinal bacteria. It is attracting attention for its potential to support women's health and beauty due to its ability to mimic the action of female hormones. However, not everyone can produce equol naturally; studies suggest that only around half of the Japanese population has the gut microbiota necessary to generate it.*¹

■ Otsuka's Initiatives to Promote Women's Health

Otsuka has long been committed to addressing the physical and mental changes women experience across different life stages. Our research into menopausal symptoms and premenstrual syndrome (PMS) began in 1996. In 2002, we successfully isolated Lactococcus 20-92, a strain capable of producing equol. Since then, we have conducted extensive domestic and international research on the efficacy and safety of equol derived from fermented soybean sprouts using this strain. In addition to our research, we collaborate with medical professionals to offer seminars and online resources that provide women with accessible, reliable information. Through these efforts, we aim to support women in managing their health and enhancing their quality of life at every stage.

Reference：Corporate Website: Women's Health https://www.otsuka.co.jp/en/nutraceutical/about/womens-health/

About Otsuka

Otsuka Pharmaceutical Co., Ltd. is a total healthcare company that focuses on each individual's potential to enhance their well-being. Our medical-related business provides treatments and diagnostics for both physical and mental health. Our nutraceutical business supports daily health maintenance and improvement. Otsuka's unique products and services are based on scientific evidence, under the guidance of our corporate philosophy: Otsuka-people creating new products for better health worldwide.

For further information, please visit. www.otsuka.co.jp/en/