The randomized controlled trial titled "Combined levothyroxine plus liothyronine compared with levothyroxine alone in primary hypothyroidism" (JAMA, 2003, PMID: 14665656) investigated whether combination therapy with levothyroxine (T4) and liothyronine (T3) provided additional benefits compared to T4 alone in patients with primary hypothyroidism. In this study of 46 patients aged 24–65
