Hypothyroidism refers to hypothyroidism, which cannot be determined by oneself, and needs to be judged by a specialist based on clinical examination, clinical symptoms and blood tests. 1. Clinical examination: Patients with hypothyroidism may have rough skin, dry hair, pale complexion and low body temperature. 2. Clinical symptoms: Decrease in the secretion of thyroid hormone level will lead to obvious metabolic abnormalities, which are mainly manifested as chills, anorexia, constipation, weight gain, fatigue, depression, slow reaction and bradycardia. 3. Blood tests: Through blood tests, free T3 and T4 levels decrease (free T3 is less than 2.33ng/l, free T4 is less than 8.9ng/l), and TSH levels increase (more than 10mIU/L). Some patients with a slight increase in TSH level (5~10mIU/l) and normal free T3 and T4 levels, with no clinical symptoms per se, are subclinical hypothyroidism. Hypothyroidism cannot be determined on its own and requires diagnosis by a specialist. If you have symptoms related to hypothyroidism, you need to consult a doctor in time and standardize the treatment under the guidance of the clinician.