What to watch with FT4 and Langlebigkeit?

The question about FT4 (free thyroxine) and longevity is complex. Thyroid hormones regulate metabolism, and both too high and too low FT4 levels have been associated with increased mortality. Some studies suggest that low-normal FT4 levels may be linked to extended lifespan, similar to caloric restriction. However, the evidence is observational and not conclusive. Individual genetic factors (e.g., in the TSH receptor) can influence the optimal FT4 range. A MyBody-X test can measure FT4, but a single reading is not diagnostic due to diurnal variation. Consult an endocrinologist before making any changes. Thyroid dysfunction should be evaluated medically.