I just thought I'd display a typically useless trial that seeks to discover if combination treatment is superior to T4 only. The trial selects only 32 patients at random. Knowing 85-90% will be satisfactory on T4 only, then only 3-4 could possibly benefit at random. Far too small a number to be detected. This is just one more example of the lack of understanding of medical researchers on this topic, which has been repeated again and again.
Treatment of hypothyroidism with levothyroxine plus liothyronine: A randomized, double-blind, crossover study
Article in Arquivos brasileiros de endocrinologia e metabologia 60:1-11 · December 2016
DOI: 10.1590/2359-3997000000192