Women's hormone health shapes energy, mood, metabolism, and disease risk across all life stages. Dr. Sara Gottfried explains which biomarkers to track by decade—from cortisol in teens to cerebral metabolism in perimenopause—and reveals why oral contraceptives can shrink the clitoris by 20% while offering actionable tools for testing, nutrition, stress management, and cardiometabolic screening. Magnesium deficiency affects 70-80% of Americans and plays a critical role in estrogen metabolism and bowel regularity, making nutritional testing in your 20s a high-impact intervention.