Serum thyroid stimulating hormone, referred to as TSH, is a very sensitive indicator of thyroid function. A decrease in serum thyroid stimulating hormone may indicate the following conditions: 1. Hyperthyroidism: In the early stage of hyperthyroidism, thyroid hormone levels may be within the normal range, but thyroid stimulating hormone changes are more sensitive and first appear to decrease, called subclinical hyperthyroidism. If you reach the clinical stage, hyperthyroidism, thyroid hormone levels begin to rise significantly, and thyroid stimulating hormone levels decrease even more significantly, often accompanied by excessive sweating, large increases in food intake, weight loss, panic, protruding eyes, decreased vision, mental hyperactivity, and enlarged thyroid gland. Generally, oral anti-thyroid drugs are needed for systemic treatment, while thyroid ultrasound and thyroid-related antibody testing are performed to further clarify the diagnosis; 2. Hypopituitarism causes secondary hypothyroidism: symptoms such as dry skin, fatigue, drowsiness, memory loss, unresponsiveness, weight gain, decreased appetite, dull gaze, indifferent expression, slow heartbeat, muscle pain and constipation; men show Men exhibit decreased sexual function, delayed sexual maturity, decreased libido, impotence or testicular atrophy; women exhibit irregular menstruation, which can cause amenorrhea in the long term, and can take Eugenol to supplement thyroid hormone; 3. Some pregnant women may have transient low serum thyroid hormone, which is due to the influence of placental hormones during pregnancy, and need to go to the hospital for thyroid function assessment to make a clear diagnosis and decide whether they need Treatment is needed.