Myths vs facts: FT4 and Langlebigkeit

The relationship between free T4 (FT4) and longevity is often discussed, but myths and facts need careful separation. A common myth is that higher FT4 levels always shorten lifespan. In reality, both low and high FT4 are associated with increased mortality in some studies, but the optimal range may shift with age. For example, slightly elevated FT4 in older adults has been linked to better cardiovascular outcomes, while subclinical hyperthyroidism increases atrial fibrillation risk. Another myth is that manipulating FT4 through diet or supplements can extend life. There is no strong evidence that FT4 optimization alone prolongs longevity; thyroid hormone therapy is only indicated for clinical hypothyroidism. The fact is that FT4 is one piece of a complex endocrine puzzle, and longevity is influenced by many factors including genetics, lifestyle, and overall health. Current evidence is observational and mixed, with no definitive causal link. Therefore, claims about FT4 and longevity should be viewed with caution.