What is Cytomel (liothyronine)? How Cytomel (liothyronine) works Cytomel (liothyronine) is a synthetic version of the T3 thyroid hormone made by your thyroid gland. Thyroid hormones have important functions like controlling metabolism, body temperature, heart rate, and more. When the amount of hormone is too low, taking thyroid replacement hormones can bring your levels back to normal. What is Cytomel (liothyronine) used for? Hypothyroidism Thyroid cancer (with radiation and surgery) Thyroid suppression test Typical dosing for Cytomel (liothyronine) The dose of Cytomel (liothyronine) will vary from person to person based on why they are taking it, and their labs values. Hypothyroidism: The typical dose range is 25 to 75 mcg once daily Thyroid cancer: Dose will depend on the target TSH (thyroid stimulating hormone) level set by your provider Thyroid suppression test: 75 to 100 mcg once daily for 7 days THIS PRODUCT IS NOT INTENDED TO TREAT, CURE OR DIAGNOSE ANY CONDITION OR DISEASE AND IS NOT FOR HUMAN CONSUMPTION