There are several common reasons for hair loss: first, normal physiological phenomenon. Hair is in a state of dynamic equilibrium, even a completely healthy person will shed a certain amount of hair every day, as long as the overall hair volume is more stable can be considered normal. Second, resting hair loss. In the case of alternating seasons or relatively tired, the number of hair loss may be slightly more but throwing not more than 100 per day belongs to the normal range, generally after 1-3 months of natural recovery can be. Third, malnutrition, childbirth and other effects, is the most common type of hair loss in young women and dieting, pregnancy, childbirth, hormonal changes in the body related. Fourthly, seborrheic alopecia, the most common type of hair loss in men, is related to genetics, irregular work and rest, and staying up late.