What role does FT4 play in Langlebigkeit?

The role of free thyroxine (FT4) in longevity is a complex and not fully resolved area of research. The provided context contains no direct information on FT4 or thyroid hormones. Generally, thyroid hormones regulate metabolism, and both hyper- and hypothyroidism have been associated with increased mortality. Some studies in centenarians suggest slightly lower thyroid activity, which is discussed as a potential protective mechanism. However, these are observational studies with moderate evidence. Without specific context data, a definitive statement on FT4's role in longevity is not possible. The evidence level is best described as unclear, and no consensus exists. For individual health decisions, a physician should be consulted.