Overactive thyroid or hyperthyroidism is used when the tissues of thyroid gland become overactive which causes overproduction of thyroid hormones in the body. This is because the tissues of thyroid gland become hyperactive. There are basically two types of thyroid hormones namely thyroxine and triiodothyronine. Thyroid hormone is quite important for the proper functioning of human body. Thyroid hormones play many important roles which are vital for a healthy body. It functions as a stimulus to metabolism and affects each and every cell of the body. However when a person suffers from overactive thyroid the metabolism increases very much. read more...