Can FT3 help with Langlebigkeit?

The question of whether free triiodothyronine (FT3) can promote longevity is scientifically unresolved. FT3 is the active thyroid hormone that regulates metabolism. Some epidemiological studies and animal models suggest that a slightly reduced thyroid activity (lower FT3 levels) may be associated with extended lifespan, as seen in centenarians. This is discussed as 'low-T3 syndrome' or adaptive hypothyroidism. However, overt hypothyroidism is clearly harmful, increasing cardiovascular and cognitive risks. The evidence is mainly mechanistic and observational, not from interventional trials. Therefore, deliberately lowering FT3 for longevity is not recommended. In healthy individuals, FT3 should remain within the normal range. Any intervention should be guided by a physician. In summary: there are intriguing hints but insufficient evidence to support FT3 manipulation for longevity.