People with hyperthyroidism may become hypothyroid by taking isotopes, there is no certainty that they will become hypothyroid. Hyperthyroidism isotope treatment is usually taking iodine 131, which is a radioactive isotope of the element iodine. Through radioactive iodine, which is highly ingested by the thyroid gland, iodine 131 releases beta rays, which have a damaging effect on the thyroid gland, sclerosing the follicular epithelium of the thyroid gland and decreasing the secretion of thyroid hormones, thus improving hyperthyroidism. If iodine 131 is not treated properly it may lead to permanent hypothyroidism, causing irreversible damage and requiring long-term thyroid hormone supplementation. It may also lead to exacerbation of hyperthyroidism or induce hyperthyroid crisis. Therefore, hyperthyroid patients taking isotopes may become hypothyroid. In addition, it is recommended that patients with hyperthyroidism experience discomfort during treatment, go to the hospital in a timely manner, and use the medication as prescribed by the doctor.