Levothyroxine, commonly known as L-thyroxine, is a hormonal supplement for the thyroid hormone called thyroxine which may be administered orally or in injection form. It is used in conditions involving thyroid disorders such as goiters and cancers and for a deficiency of thyroxine levels in the body which may be due to insufficient secretion by the thyroid gland.
Underactivity of the thyroid may be attributed to injury or the removal of the thyroid gland. The activity of the thyroid gland is necessary for proper mental and physical development in growing children. Levothyroxine may also be used to treat infertility which is caused by low levels of thyroid hormone in the body.