The effect of hypothyroidism on weight usually results in weight gain. Hypothyroidism is primarily a disease in which the production of thyroid hormones is reduced, resulting in a range of symptoms due to a decrease in the body’s metabolic rate and a decrease in sympathetic excitability. In hypothyroid patients with basal metabolic rate, weight gain is mainly due to the retention of body fluids leading to facial swelling, mucous edema and a decrease in basal metabolic rate, resulting in a decrease in the body’s metabolism, the patient’s less movement and laziness, a decrease in energy consumption, and weight gain resulting from the intake being greater than the consumption. Early patients with mild hypothyroidism can have no specific symptoms. Typical patients have symptoms such as chills, fatigue, drowsiness, memory loss, less sweating, weight gain, constipation, and menstrual disorders in women. If the patient has a history of hypothyroidism and weight gain, it should be taken seriously and actively seek medical treatment.