liothyronine + levothyroxine

Liothyronine (synthetic triiodothyronine, T3) and levothyroxine (synthetic thyroxine, T4) are synthetic thyroid hormones used for hormone replacement therapy in patients with hypothyroidism. This specific research context refers to a clinical study conducted by the **National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)** at the NIH Clinical Center. The study evaluates the metabolic effects of these two therapies, comparing standard levothyroxine monotherapy against liothyronine monotherapy or combination approaches. While levothyroxine is the standard of care, some patients remain symptomatic or exhibit metabolic abnormalities, potentially because T4 monotherapy may not restore physiological T3 levels in all tissues. The NIDDK research utilizes randomized, double-blind, crossover trials to assess outcomes such as lipid metabolism, glucose regulation, and energy expenditure at doses that normalize thyroid-stimulating hormone (TSH) levels.

Other names

T3 + T4triiodothyronine + thyroxineliothyronine and levothyroxine