Levothyroxine sodium is a typical medicine used to treat hypothyroidism, which is characterised by an underactive thyroid gland. Thyroxine (T4), a hormone that the thyroid gland makes, is crucial for controlling a number of biological processes, including metabolism, growth, and development. The thyroid gland does not produce enough thyroxine in people with hypothyroidism, which can cause a variety of symptoms such fatigue, weight gain, cold intolerance, and depression. Levothyroxine sodium is a synthetic version of thyroxine that functions by supplementing or replacing the hormone that the body lacks. It comes in tablet form, and is normally taken orally once day, preferably in the morning, on an empty stomach.