The relationship between levothyroxine dosage and free thyroxine levels in hypothyroid patients: a large retrospective study

The findings emphasize the importance of higher free thyroxine levels for maintaining adequate free triiodothyronine in levothyroxine-treated patients, underscoring the need to monitor free thyroxine, free triiodothyronine, and their ratio during therapy to optimize treatment outcomes. In addition, clinicians should recognize that higher levothyroxine doses may elevate free thyroxine levels beyond the reference range.