Thyroid stimulating hormone 0.25mU/L, below the normal reference value range of 2-10mU/L, abnormal, the index of lowering may be related to certain diseases (hyperthyroidism, secondary hypothyroidism, etc.) and taking drugs (glucocorticoids, anti-thyroid drugs, etc.). 1. Diseases: As thyrotropin is affected by thyrotropin-releasing hormone and thyroxine, when it is generally lowered, it is commonly found in hyperthyroidism, secondary hypothyroidism, hypopituitarism, hypercortisolism and other diseases. 2. Drugs: excessive application of glucocorticosteroids such as prednisone and antithyroid drugs such as methimazole may also cause a decrease in this index. When the value of thyroid hormone is low, you should improve the relevant examination under the guidance of the doctor, to clarify the cause of the disease, and actively treat it, so as to avoid delaying the condition.