Levothyroxine is used to treat hypothyroidism, a condition where the thyroid gland does not produce enough thyroid hormone. This medicine is also used to help decrease the size of enlarged thyroid glands (also called a goiter). Levothyroxine, also known as L-thyroxine, is a synthetic form of the thyroid hormone thyroxine (T 4). [4][7] It is used to treat thyroid hormone deficiency (hypothyroidism), including a severe form known as myxedema coma. [4] It may also be used to treat and prevent certain types of thyroid tumors. [4] It is not indicated for weight loss. [4] The thyroid gland produces thyroid hormones using iodine absorbed from dietary intake. Levothyroxine is prescribed to treat hypothyroidism, a condition in which the thyroid gland produces insufficient thyroid hormones. Levothyroxine medication replaces or supplements deficiency in natural thyroxine. Levothyroxine oral tablets are used to treat hypothyroidism, goiter, and certain types of thyroid cancer. Learn about the drug's uses, interactions, and more. Levothyroxine is used in adults and children to treat hypothyroidism (underactive thyroid - a condition where the thyroid gland does not produce enough thyroid hormone). Levothyroxine is also used in adults along with surgery and radioactive iodine therapy to treat a certain type of thyroid cancer. Overview: Levothyroxine is used as a replacement hormone therapy for people with low thyroid hormone levels, among other uses. Levothyroxine interacts with many medicines and health conditions. But, what exactly is levothyroxine? Levothyroxine is a form of thyroid hormone replacement medication and it is the most common medication used to treat hypothyroidism (low thyroid function). This thyroid medication contains the inactive thyroid hormone T4 (also known as LT4 and Thyroxine). Here are 10 things you should know before taking levothyroxine, including what it’s for, side effects, brands, cost, and more. Levothyroxine is a synthetic version of a hormone called thyroxine. It replaces thyroxine if your thyroid gland cannot produce it and prevents the symptoms of hypothyroidism. Levothyroxine starts working straight away, but it may be several weeks before your symptoms start to improve. Levothyroxine is used to treat hypothyroidism (condition where the thyroid gland does not produce enough thyroid hormone). It is also used with surgery and radioactive iodine therapy to treat thyroid cancer.