Thyroid hormones are naturally synthesized in our body, but since the molecules are not complex, many pharmaceutical companies make the synthetic variety of the hormones. There are two basic types of thyroid hormones-
T4 known as levothyroxine
T3 known as liothyronine.
Both are manufactured and stored in the thyroid gland.
Thyroid hormone from the pharmaceutical companies are obtained in 2 ways.- either derived from animal thyroid gland (bovine or ovine sources) or made synthetic. In the USA, the content and quantity of iodine in the thyroid preparation is well regulated.
Cytomel (liothyronine sodium) is available both as a tablet or the salt of a naturally occuring thyroid hormone. T3 is many times more potent that T4 Pharmacology How thyroid hormones actually work is not really known but their actions involve myriad biochemical changes in the cells.
