what is an underactive thyroid
Hypothyroidism, also known as underactive or low thyroid, is a condition in which the thyroid gland does not produce sufficient amounts of thyroid hormones which are important for many functions of the body (metabolism).hyroid hormones direct many of the body's processes. An underactive thyroid does not produce enough hormones. This condition is also referred to as hypothyroidism. It slows down the metabolism, which may cause fatigue, lethargy, or constipation, but these kinds of symptoms can also have a number of other causes.