The three thyroid function tests mainly include TSH, T3 and T4. Combining the indicators of these three tests, we can determine whether the thyroid function is abnormal. Generally speaking, the pituitary gland stimulates the thyroid gland to release thyroid hormones by secreting TSH, and thyroid hormones have a regulatory effect on various target organs and tissues in the human body. If the balance between the pituitary gland and the thyroid gland is disturbed, thyroid disorders are likely to occur. If T3 and T4 are increased and TSH is decreased, the body is overproducing thyroid hormones, which means hyperthyroidism. Patients with hyperthyroidism are prone to irritability, increased appetite, memory loss, and even protruding eyes and hyperactive gastrointestinal tract.