It is also known as premature baldness, alopecia areata, hereditary alopecia, seborrheic alopecia, and diffuse alopecia. There are male pattern and female pattern alopecia. It is the most common type of hair loss in men. The prevalence is quite high, often developing around the age of 20 to 30, and its main genetic factor, which can have a family history. These patients have high androgen secretion in their bodies or normal androgen secretion in their bodies, but the genetic qualities make the hair more sensitive to the biological effects of androgens, making the hair growth period shorter, the resting period longer, a large number of hair follicles shrink, and the hairs become thinner. In addition, androgen secretion is high, which can lead to hypertrophy of sebaceous glands and hyper-secretion to produce more oil. The largest and most abundant sebaceous glands in the body are on the scalp, forehead, cheeks and nose, followed by the back of the chest, where excess oil makes the scalp and hair look greasy. Since the sebaceous glands open at the cheek of the hair follicle, excessive oil causes the mouth of the scalp follicle to be blocked, creating a barrier to scalp nutrition and gradually shrinking hair follicles, resulting in hair loss. If this is accompanied by sleep disorders and excessive mental stress, it will aggravate the endocrine disorders, thus affecting the normal function of hair follicles, nerves, muscles and blood vessels, making hair loss more serious. Its performance is: hair loss or from the forehead, the front hairline receding backward, the forehead becomes high, gradually extended to the top of the head, or from the top of the head, and then extended to the forehead, in serious cases the entire top of the head hair all fall off, leaving only the occipital and bilateral temporal hair, like the “Mediterranean”, hair loss area smooth skin, or a few sparse and soft short hair remains. Hair loss progresses slowly.