(1) endocrine effects of male hormones stimulate the growth matrix cells an important role. If adrenal androgen secretion can lead to female HIRSUTISM. If the pituitary gland function degradation, hair may reduce or fall off. Testosterone can also act directly on the hair follicles, causing male pattern hair loss, who lack male hormones will not occur. Role of estrogen against male hormones, so few women before menopause appear similar to men's hair loss. Thyroid function is normal or not, play an important role in the growth of hair. When if it's dysfunctional, eyebrow and temple outside 1/3 of hair shedding can occur, when the function is, not only decrease color is gray and white and hair will also appear to reduce or shed.
(2) the racial ethnic differences is a distinct phenomenon, people of different races, not only different hair color, growth of hair and also made a difference. As mentioned earlier, yellow and white, black hair growth is different. In addition, the phenomenon of different races have different hair loss, male pattern hair loss is common in Caucasians, people in China is relatively small, while the Indians are even rarer.
(3) genetic hair growth are under genetic control, in the same House, hair growth often broadly consistent. In addition, male pattern hair loss and other hair diseases and genetics have close relations.
(4) mental stress, fear, anxiety, hair loss can be significantly increased.
(5) diseases of certain systemic diseases, like fever disease, anemia, malnutrition, liver disease and serious wasting disease, can often lead to thinning hair.