Is FT3 useful for Blutzucker?

FT3 (free triiodothyronine) is a thyroid hormone that influences basal metabolic rate and indirectly affects glucose metabolism. Hyperthyroidism can raise blood glucose, while hypothyroidism is linked to insulin resistance. However, FT3 is not a validated biomarker for managing blood sugar in metabolically healthy individuals or diabetics. Evidence is limited to physiological mechanisms; no robust clinical trials support routine FT3 measurement for glycemic control. In practice, FT3 is used to diagnose thyroid disorders, not to optimize blood sugar. For improving blood sugar, focus on established markers like fasting glucose, HbA1c, and insulin. FT3 testing is only warranted if thyroid dysfunction is suspected. Evidence grade: mechanistic.