Boys face sweat hair long may be due to physiological phenomenon, endocrine disorders, genetic and other reasons. 1. Physiological phenomenon: after the boys reached puberty, due to the rise in androgen levels in the body, stimulate the skin, dermal follicles proliferation, which can appear on the face of the phenomenon of long hair, which is a physiological phenomenon. 2. Endocrine disorders: due to certain reasons, some endocrine glands or cells in the body can not normally secrete hormones, too much secretion, too little or even can not be secreted, resulting in an imbalance of hormones. When there is excessive secretion of androgens, the phenomenon of long facial hair may occur. 3. Heredity: If the boy’s parents both have the phenomenon of long facial hair. According to genetics, the probability of the boy being inherited is also greater. It is recommended that boys with long facial hair go to the hospital in time and follow the doctor’s instructions for treatment to avoid delaying the condition.