The observational study titled "Combined levothyroxine plus liothyronine compared with levothyroxine alone in primary hypothyroidism: a randomized controlled trial," published in the Journal of Clinical Endocrinology & Metabolism (1970, PMID: 4986007), explored peripheral conversion of thyroxine (T4) to triiodothyronine (T3) in athyreotic (thyroid-removed) patients. The findings confirmed the body's ability
