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T4 Monotherapy Limitations

Meaning

T4 Monotherapy Limitations describe the clinical challenges and physiological shortcomings associated with treating hypothyroidism solely with levothyroxine (L-T4), the synthetic form of thyroxine (T4). While T4 is the prohormone, its effectiveness relies entirely on the body’s ability to efficiently convert it into the biologically active triiodothyronine (T3) within target tissues. For a significant subset of patients, genetic variations or systemic factors impair this conversion, leading to persistent hypothyroid symptoms despite normal TSH levels, underscoring the limitation of relying on a single hormone replacement.