The main differences between hypothyroidism and hyperthyroidism are as follows: a. Symptoms: Hypothyroidism is mainly characterized by fear of cold, little or no sweating, puffiness of the face and eyelids, weight gain, poor nutrition, unresponsiveness and other hypometabolic symptoms. Hyperthyroidism, on the other hand, is mainly characterized by high metabolic symptoms, such as fear of heat, excessive sweating, easy to eat and hunger, thinness and excitement. In terms of heart, hypothyroidism can occur as slow heart rate, lower blood pressure and pericardial effusion. Hyperthyroidism, on the other hand, is characterized by panic attacks, increased heart rate, increased systolic blood pressure and arrhythmia. Lipids: Hypothyroidism can be affected by thyroid hormones, while hyperthyroidism can have decreased cholesterol levels. Laboratory tests show that hypothyroidism is characterized by lower T3 and T4 and higher TSH, while hyperthyroidism is characterized by higher T3 and T4 and lower TSH. V. Treatment is different. Hypothyroidism is mainly thyroxine replacement therapy, while hyperthyroidism requires anti-thyroid medication.