Hypothyroidism (referred to as hypothyroidism) is a disease caused by a decrease in the body’s thyroid hormones, or the inability of synthesized thyroid hormones to function. Depending on the age of onset, hypothyroidism can be divided into five categories: cretinism (fetal hypothyroidism), juvenile hypothyroidism (hypothyroidism that occurs before puberty), adolescent hypothyroidism, adult hypothyroidism, and geriatric hypothyroidism. Adolescent hypothyroidism refers to hypothyroidism that occurs during adolescence and has a significant impact on the growth and development of adolescents. 1, the etiology of adolescent hypothyroidism: the primary hypothyroidism of the thyroid gland accounts for about 95% of the population. Hypothyroidism in adolescence has its own unique characteristics: after entering puberty, the body’s need for thyroxine increases, thus causing a relative lack of iodine in the body, if the iodine content in the diet is insufficient at this time, or the body itself has a potential deficiency of thyroid function, hypothyroidism will occur. Other common causes are chronic lymphocytic thyroiditis and subthyroiditis. Secondary hypothyroidism due to pituitary lesions is also not uncommon. 2, adolescent hypothyroidism on the body: In addition to the rapid development of the reproductive system, adolescence, respiratory, circulatory, digestive, metabolic, hematopoietic, immune, neurological, endocrine and other physiological functions have different degrees of development. If thyroid hormone deficiency is caused by iodine deficiency at this time, it will definitely affect the development of various systems, especially the development of reproductive system and sexual organs. In severe cases, male patients may suffer from decreased libido, impotence, reduced sperm count and infertility; in female patients, menstrual disorders may occur, including excessive menstruation, amenorrhea and scanty menstruation, which may lead to infertility if left untreated.