Hormone Testing by Decade: What Women Should Track and When

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Dr. Sara Gottfried, a Harvard-trained gynecologist, recommends women begin benchmarking key hormones — estrogen, progesterone, testosterone, cortisol, and thyroid — in their 20s or 30s, when levels are more stable than in the teen years. She favors dried urine testing over standard blood draws because it captures hormone metabolites (the breakdown products that reveal how your body processes hormones), not just hormone levels, though blood tests are cheaper and more likely to be covered by insurance. Timing matters: for women with a regular 28-day cycle, day 21–22 is the preferred window; as cycles shorten in perimenopause, testing should move earlier, around day 19–20. She also stresses micronutrient testing — especially magnesium, B vitamins, and antioxidants like glutathione — because deficiencies directly affect hormone production and long-term disease risk.