16-year-old hair thinning if caused by genetic factors generally do not need treatment, caused by seborrheic alopecia can be used minoxidil, etc., caused by baldness can be used glucocorticoids. 1. Heredity: If the hair is thinning since childhood, it can be caused by genetic factors, generally no special treatment, usually can strengthen the intake of nutrients to reduce the phenomenon of hair loss. 2. Seborrheic alopecia: If there is seborrheic alopecia, there can be excessive hair oil and other phenomena, you can use topical minoxidil treatment. 3. Patchy baldness: In patchy baldness, there will be limited patchy hair loss, which can be treated with topical glucocorticosteroids such as dexamethasone ointment or topical minoxidil. If hair thinning occurs, go to the hospital in time for examination, the use of the above drugs should follow the doctor’s instructions.