04/12/2026
T2 is not superior to T3
The higher dose of T2 used was 80 times that of T3. Thus, it allows for its estimated lower affinity for the TH receptors, assuming that the affinity of T3 for the receptors is indeed 100 times that of T2 (8). This high dose of T2 essentially mimicked all the physiological effects obtained with the T3 dose. These effects included suppression of the HPT axis, decreases in fat mass, serum leptin and cholesterol, and increases in lean mass, food intake, and hepatic expression of TH-dependent genes relevant to lipid metabolism (see summary of results in Table 1). After 4 weeks, this high dose of T2 also caused cardiac hypertrophy and resulted in elevated metabolic rate and body temperature. These results demonstrate that at a dose that corrects for its decreased affinity for the TH receptor, T2 is capable of producing the same biological effects as T3.
