T3-100(liothyronine sodium) Tablets contain liothyronine (L-triiodothyronine or LT3 ), a synthetic form of a natural thyroid hormone, and is available as the sodium salt. The structural and empirical formulas and molecular weight of liothyronine sodium are given below. L-Tyrosine, O -(4-hydroxy-3-iodophenyl)-3,5-diiodo-, monosodium salt Twenty-five mcg of liothyronine is equivalent to approximately 1 grain of desiccated thyroid or thyroglobulin and 0.1 mg of L-thyroxine.

Each round, yellowish T3-Cytomel (liothyronine sodium) tablet contains liothyronine sodium equivalent to liothyronine 100 mcg. Inactive ingredients consist of calcium sulfate, gelatin, starch, stearic acid, sucrose and talc.