was ist ft3 und ft4 — what does this mean exactly?

FT3 and FT4 are the free (unbound) forms of the thyroid hormones triiodothyronine (T3) and thyroxine (T4). They are measured in blood to assess thyroid function. FT4 is the prohormone produced by the thyroid gland, while FT3 is the biologically active form, mainly generated by conversion from FT4 in peripheral tissues. Together with TSH (thyroid-stimulating hormone), they help diagnose hyperthyroidism or hypothyroidism. Elevated FT3/FT4 with low TSH suggests hyperthyroidism; low values with high TSH indicate hypothyroidism. However, a single measurement without clinical context is insufficient for diagnosis. The Men’s Wellness Check mentioned includes TSH but may not include FT3/FT4 – this should be verified before purchase. Individual results can be influenced by medications, inflammation, or non-thyroidal illness syndrome. The evidence for the clinical utility of FT3/FT4 is strong (human-strong), but a self-test does not replace a medical evaluation.