What to watch with FT3 and Wechseljahre?

FT3 (free triiodothyronine) is the active thyroid hormone that regulates metabolism. During menopause, hormonal shifts can cause symptoms like fatigue, weight gain, and mood changes—similar to thyroid disorders. However, FT3 alone is not a reliable marker for thyroid function in this life stage. Guidelines primarily recommend TSH and free T4 (FT4) for assessment. FT3 can be influenced by non-thyroidal illness, calorie restriction, medications (e.g., beta-blockers, amiodarone), and biotin in supplements. Direct-to-consumer tests often measure only FT3, which can lead to misinterpretation. Women in menopause should consult a doctor if thyroid issues are suspected and request a full thyroid panel (TSH, FT4, FT3, antibodies). The evidence for a specific FT3 cutoff in menopause is moderate; clinical decisions should be based on the overall picture. Safety note: Do not self-medicate with thyroid hormones based on FT3 alone.