The causes of heavy lip hair are mainly categorized into physiological and pathological. Physiological causes include heredity, etc. Pathological causes include polycystic ovary syndrome. 1. Physiological reasons Genetic factors: If there are no relevant pathologic factors, women with more lip hair than normal people are often considered to be caused by genetic factors, and their offspring generally have heavier lip hair. Increased secretion of androgens: when men go through puberty, due to the large secretion of androgens, lip hair will be significantly aggravated, which is a normal physiological development process. 2. Pathological causes Polycystic ovary syndrome: this disease is often characterized by abnormally high levels of androgens in the body, and clinical symptoms are often manifested as an increase in hair on the whole body, including lip hair, in addition, there will be obesity, menstrual abnormalities, acne, infertility and other symptoms. Congenital Adrenocortical Syndrome: This disease is also characterized by an increase in hair on the whole body, including lip hair in women, and beard and pubic hair in men. If there is an abnormal increase in lip hair, go to the regular hospital in time and complete the relevant examinations to exclude or confirm the diagnosis of certain pathological factors in order to obtain the best prognosis.