Hair loss is a relatively common symptom, which is mainly seen in physiological hair loss and pathological hair loss (such as androgenetic alopecia, baldness, and resting hair loss). 1. Physiological alopecia: there are three periods of hair growth, i.e. anagen, telogen effluvium and alopecia areata. Every day, a part of the hairs in the alopecia areata period will fall off, so normal people will lose their hairs every day, and usually not more than 100 hairs, which is a normal physiological phenomenon. 2. Pathological hair loss: (1) Androgenetic alopecia: also known as seborrheic alopecia, the cause of its development is mainly related to heredity and androgen. Androgen mainly comes from testosterone, which can be converted into dihydrotestosterone, which can lead to the miniaturization of hair follicles, or even lead to the atrophy and disappearance of hair follicles, which is the main cause of androgenetic alopecia. (2) Patchy baldness: it is also called ghost shaved head, the cause of its onset is not only related to heredity, but also related to mental factors and endocrine abnormalities. (3) Resting Hair Loss: Commonly seen in women’s post-partum hair loss, due to the body’s estrogen secretion level has not completely returned to normal within a short period of time, resulting in a low level of state, so it is prone to the phenomenon of hair loss. If the amount of hair loss exceeds 100 hairs per day, it is recommended to go to a regular hospital for consultation and standardized treatment under the guidance of a doctor after a clear diagnosis.