was ist ft3 — can a DNA test help?

FT3 (free triiodothyronine) is the active thyroid hormone regulating metabolism. A DNA test can detect variants in genes like DIO2 (rs225014) or THRB, which may slightly influence hormone conversion or receptor sensitivity. However, effects are small, polygenic, and overshadowed by iodine status, stress, medications, and illness. No DNA test can diagnose thyroid dysfunction or replace clinical FT3 measurement. Guidelines (e.g., ATA) recommend TSH and free T4 as first-line tests; FT3 is rarely used alone. Using a DNA test to guide diet or supplements for FT3 is not evidence-based and borders on marketing. For symptoms like fatigue or weight changes, see a doctor for proper lab work. Under German GenDG, predictive genetic testing for non-medical purposes is restricted. In summary: a DNA test does not help understand or optimize FT3 levels.