The main treatment for hypothyroidism is thyroid hormone supplementation as prescribed by the doctor. Hypothyroidism, referred to as hypothyroidism in clinical practice, is a generalized hypometabolic syndrome caused by hypothyroxinemia for various reasons. Typical clinical manifestations of hypothyroidism include fatigue, chills, drowsiness, facial edema, slow response, and decreased skin temperature. Currently, the main treatment for hypothyroidism is thyroid hormone supplementation. It takes 4-6 weeks to re-establish the balance of the hypothalamic-pituitary-thyroid axis by replenishing thyroid hormones, so at the beginning of the treatment, serum TSH and FT4 should be measured at intervals of 4-6 weeks, and drug dosage should be adjusted according to the levels of TSH and FT4 until the therapeutic target is reached. After the treatment reaches the target, the above indexes need to be rechecked at least once every 6~12 months. Levothyroxine is mainly used for the replacement therapy of hypothyroidism. Adverse effects include palpitations, excessive sweating, tremor and other symptoms of hyperthyroidism, and the drug needs to be discontinued if the above symptoms occur. The treatment of hypothyroidism and the adjustment of drug dosage should be carried out under the guidance of physician.