Hair is a kind of protein filament, which grows from hair follicles in dermis or skin. Hair is one of the characteristics of mammals. In addition to the smooth areas of the skin, the body is covered with hair follicles, which produce dense terminals and short, thin hairs. The most common interests of hair are focused on hair growth, hair type and hair care, but hair is also an important biomaterial, mainly composed of proteins (especially keratin).

In different cultural and historical periods, attitudes to different hair (such as hair style and hair removal) vary greatly, but are often used to indicate a person's personal beliefs or social status, such as age, gender or religious beliefs.

All natural hair colors are the result of two types of hair dyes. Both pigments are melanin type, which are produced in the hair follicles and accumulate in the granules found in the fibers. Eumelanin is the main pigment in brown and black hair, while pheomelanin is the main pigment in red hair. Golden hair is the result of almost no pigmentation on the hair. White hair occurs when melanin production is reduced or stopped, while polio is hair (usually skin attached to the hair) (usually spots), and does not have melanin at all from the beginning, or stops for natural genetic reasons, usually white hair. In the first few years of life.