Hormone replacement therapy (HRT) has been one of the most misunderstood areas of women’s health over the past two decades. The FDA recently changed its stance on the guidelines for women. Understanding how we arrived here requires revisiting the landmark research that changed menopause care and examining what we now know.

One of the biggest reasons for this disconnect is that Hashimoto’s is not simply a thyroid hormone deficiency. It is a chronic autoimmune disease. When the immune system mistakenly targets the thyroid gland, hormone production may eventually decline, but the autoimmune process itself often begins long before standard thyroid labs become abnormal. How we define Hashimoto’s matters because the definition drives treatment.