Levothyroxine is a manufactured form of the thyroid hormone thyroxine (T4).
It is typically used to treat hypothyroidism, and is the treatment of choice for people with hypothyroidism, who often require lifelong thyroid hormone therapy. It may also be used to treat goiter via its ability to lower thyroid-stimulating hormone (TSH), which is considered goiter-inducing.
Levothyroxine is also used as interventional therapy in people with nodular thyroid disease or thyroid cancer to suppress TSH secretion. It is also used to treat subclinical hypothyroidism, which is defined by an elevated TSH level and a normal-range free T4 level without symptoms.
It is also used to treat myxedema coma, which is a severe form of hypothyroidism characterized by mental status changes and hypothermia.
