Myths vs facts: FT3 and Wechseljahre

FT3 (free triiodothyronine) is the active thyroid hormone, but its role in menopause is often misunderstood. Myth: Low FT3 causes hot flashes, weight gain, or fatigue during menopause. Fact: Menopausal symptoms are primarily driven by estrogen decline, not FT3. Thyroid function changes with age, but an isolated low FT3 with normal TSH and FT4 is usually benign (euthyroid sick syndrome or normal variation) and does not warrant thyroid hormone replacement. Unnecessary treatment can lead to overmedication and cardiac risks. Clinical guidelines recommend against routine FT3 testing in menopause; instead, assess TSH and FT4 if thyroid disease is suspected. Evidence is practice-based: no high-quality RCTs support FT3-guided management in perimenopause. Caveat: reference ranges are not menopause-specific, and symptom overlap (fatigue, weight changes) often leads to misinterpretation. Always interpret FT3 in context of full thyroid panel and clinical presentation.