Is it true that “a decline in female hormones causes health issues”? “The New Truth About Hormonal Balance”: Turning Anxiety and Fear into Joy On sale August 29

From Irregular Periods and PMS to Premenopause and Menopause— A book that reexamines women’s minds and bodies not through “hormone levels” but through “balance”

2026.08.27 10:00

Hyogen-sha Co., Ltd.

Hyogen-sha Co., Ltd. (Minato-ku, Tokyo) will release a new book titled *The New Essentials of Hormonal Balance for Women to Stay Beautiful Throughout Their Lives*, written by Aya Sasaki, an obstetrician-gynecologist and director of the AYA Women’s Clinic, on August 29, 2026.

URL: https://www.amazon.co.jp/dp/4828207627/

A woman’s mind and body undergo various changes depending on her stage of life, including menstrual cramps, PMS, irregular periods, premenopause, menopause, fatigue, and sleep and mental health issues.

Regarding these conditions unique to women, this book focuses not merely on simple “fluctuations in female hormones,” but on the balance of hormones such as estrogen and progesterone.

Drawing on her clinical experience as an obstetrician-gynecologist who has treated over 100,000 women, the author explains the concept of “hormonal balance”—essential knowledge for women to understand their own bodies and cope with the changes they experience at each stage of life.

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■Why Focus on “Hormonal Balance” Now?

A woman’s body undergoes hormonal changes throughout her life—from puberty to adulthood, through pregnancy and childbirth, to perimenopause, menopause, and postmenopause.

The concerns that arise vary by age, including menstrual cramps, PMS, irregular periods, irritability, low mood, fatigue, insomnia, and menopausal symptoms.

The author sees many women who, despite paying close attention to their diet and exercise, taking supplements, and visiting doctors, are troubled by the fact that their symptoms “show no sign of improvement.”

The author herself says that, through her clinical work with women, she began to question cases that could not be explained solely by the conventional view that “health issues arise from a decline in female hormones.”

Therefore, this book proposes a perspective that looks at the mind and body through the balance of multiple hormones, rather than simply viewing female hormones in terms of “high” or “low” levels.

Before resigning yourself to the idea that “it’s just part of aging” or “it’s because my hormones have declined,” first take the time to understand what is actually happening inside your body.

This book provides the knowledge and options women need to deepen their understanding of their own bodies and live more healthily and authentically at every stage of life.

■ Three Key Points of This Book

1. Estrogen Isn’t the Only Important Factor: Understanding the Female Body Through “Hormonal Balance”

In today’s world, many women suffer from symptoms such as menstrual cramps and PMS (premenstrual syndrome). The author points out that in many cases, an “excess” of the female hormone (estrogen) is a contributing factor behind these symptoms.

On the other hand, when it comes to perimenopause and menopause, it is not uncommon to see information suggesting that “discomfort arises because female hormones (estrogen) decrease” or that “it’s better to supplement the lost female hormones.”

However, the author believes that when considering a woman’s mind and body, it is important not to focus solely on the level of estrogen, but rather to examine the balance between estrogen and other hormones, particularly progesterone.

Drawing on her experience providing life support to over 100,000 people through a combination of Eastern and Western medicine, holistic care for women focused on hormonal health, and the cultivation of femininity, the author unravels the functions and interrelationships of estrogen and progesterone, and explains how to cope with various changes that occur during a woman’s life stages—such as menstrual cramps, PMS,anovulatory cycles, premenopause, and menopause—from the perspective of “hormonal balance.”

2. “You Can Reset Discomfort Caused by Synthetic Hormones!” A New Perspective on the Relationship Between the Birth Control Pill and a Woman’s Body

“I want to relieve my PMS symptoms,” “I want to avoid an unwanted pregnancy,” “I want to delay my period to fit my schedule”—

The birth control pill (oral contraceptive) is widely used as an option to fulfill these wishes. Recently, some junior high school girls have even been taking it to time their periods to coincide with entrance exams or athletic competitions.

While it may seem like a convenient medication at first glance, the author sounds the alarm that taking the pill is linked to hormonal imbalances and reduced ovulatory function.Furthermore, the author points out that even at low doses, the effects accumulate, and taking the pill at a young age or using it long-term often leads to health issues later on. She argues that it is essential to fully understand the impact that synthetic hormones in the pill have on both the mind and body.

The author emphasizes that recovery is possible even for those with a history of taking the pill, and that there is no need to give up simply because of one’s age. After understanding the pill’s effects and how it impacts the body, readers are encouraged to consider how they will care for their bodies moving forward. This book provides the knowledge necessary for that journey.

3. Understanding Your Hormonal Status Through Saliva Testing and Exploring “Natural Hormone Therapy” as an Option

The first step toward balancing your hormones is to understand your “current condition.” The author incorporates saliva hormone testing as a method to measure “active hormones”—the hormones that actually act within the body. This test allows for at-home sample collection and makes it easy to track daily hormonal fluctuations.

The author also incorporates “Natural Hormone Therapy” into her clinical practice. This approach is based on the philosophy advocated by Dr. John R. Lee, M.D., author of the national bestseller *Hormone Balance: What Doctors Don’t Know* and a renowned expert in hormone research.This therapy uses “natural hormones” derived from plant-based ingredients; because they have the same chemical structure as hormones produced by the body, they have no side effects.

This therapy has become widespread primarily in Europe, the United States, and Australia, and has been used by millions of women worldwide. The author studied Dr. Lee’s insights and was one of the first in Japan to adopt natural hormone therapy, tailored to the physical constitution and lifestyle habits of Japanese women. Following Dr. Lee’s passing, she has also collaborated with hormone researchers at Harvard University in the United States who carry on his legacy.

Understand your hormonal status and find the approach that’s right for you. This book presents a new option for women to engage with their own bodies.

■ Main Content and Table of Contents

This book consists of four chapters. It provides a multifaceted explanation of women’s minds and bodies from the perspective of “hormonal balance.”

Chapter 1: Hormonal Balance and Its Role in All Physical and Mental Discomforts in Women

Menstrual Cramps and PMS and Female Hormones / Symptoms That Appear When Hormonal Balance Is Disrupted / Estrogen and Progesterone / Anovulatory Menstruation / Premenopause / Menopause / Supplements and Natural Foods / Saliva Tests and Hormonal Balance / and more

Chapter 2: The Adverse Effects of the Birth Control Pill on the Mind and Body

What Happens Inside the Body When You Take the Pill? / Side Effects of the Pill You Should Know / Adolescent Bodies and Hormonal Balance / Resetting Your Body in 4 Months Even After Long-Term Pill Use / Case Studies / and more

Chapter 3: All Women’s Physical and Mental Health Issues Stem from Adrenal Fatigue

How the Adrenal Glands Work / Stress and the Adrenal Glands / Main Symptoms and Causes of Adrenal Fatigue / Reevaluating How You Use Your Energy / Stress Management / Diet / Low-Carb Diets and Fasting / Hydration and Salt Intake / Exercise and Stretching / The Recovery Process / Case Studies, and more

Chapter 4: Why I Recommend Natural Hormone Therapy

What I’ve Learned from My Clinical Experience as an OB-GYN / The Strengths of Natural Hormone Therapy / Changes Achieved Through Natural Hormone Therapy / Five Key Points of Natural Hormone Therapy / Regaining the Ability to Regulate Your Own Health / Steps You Can Take to Live a Positive Life / and more

■Author Profile

Aya Sasaki

Director of AYA Women’s Clinic. Board-certified obstetrician and gynecologist. Representative Director of the Natural Hormone Beauty Association (a general incorporated association).

She practiced obstetrics and gynecology at university hospitals and community hospitals in Kyoto, Osaka, and Tokyo. During her time as a staff physician, she gained extensive experience not only in obstetrics and gynecology but also in emergency medicine and the NICU (Neonatal Intensive Care Unit), working across a wide range of women’s health and perinatal care settings.

She later studied endocrinology under an obstetrics and gynecology hormone researcher at Harvard University in the United States and introduced natural hormone therapy and salivary hormone testing to Japan. She opened AYA Women’s Clinic in 2016.

Through a holistic approach to women’s health—combining Eastern and Western medicine with hormone care—and by fostering the blossoming of women’s femininity, she has provided life support to more than 100,000 people in total.

Currently, in addition to providing medical care and conducting awareness campaigns centered on female hormones, she continues to give lectures and share information nationwide on topics such as menopause, alleviating physical discomfort, and healthy beauty.

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