Teenage hair loss may be a normal metabolism, may also be related to bad habits, genetic factors, of course, can not exclude some disease factors. 1, normal metabolism: each person is losing hair every day, but also in hair growth, but the overall number of hair to maintain a dynamic balance, hair volume does not significantly reduce and no other abnormal signs, generally no special treatment; 2, bad habits: if Hair loss is more serious in teenage period, which may be caused by bad living habits such as sleeping late, eating spicy food, and loving to dye hair. Teenage period is a more special period, teenage groups tend to be more curious, self-control is not strong, and hormones in an unstable state, easy to cause endocrine system disorders, androgen levels rise, scalp sebum secretion, hair root malnutrition, etc., and then cause hair loss; 3, genetic factors: genetics is also a common factor in teenage hair loss, generally male pattern baldness has a certain family gathering 4, disease factors: such as thallium poisoning, pernicious anemia, blood sugar abnormalities, thyroid function abnormalities, etc. can also lead to teenage hair loss, when the number of hair significantly reduced combined with abnormal signs, may indicate that adolescents suffer from certain kinds of diseases. Patients are advised to go to the hospital to identify the cause and to carry out appropriate treatment.