Frequent hair washing will cause the scalp’s cuticle to metabolize too quickly, which can easily cause allergic dermatitis, resulting in very serious skin allergy symptoms. Do not wash your hair too often, generally 3-4 times a week is fine. Shampooing itself will cause a certain amount of hair loss, and in the process of washing, the poor smoothness of the hair, will pull on the hair and cause mechanical damage. The skin of the head itself has a physiological regulation function, if the environment is dry, secrete more oil; if the environment is hot and humid, secrete oil will be reduced. Excessively frequent removal of oil, originally intended to keep the scalp dry, but wash every day instead will be more oil secretion. Generally, in summer, washing your hair once every other day is fine. If it is in winter, washing 1-3 times a week is enough.