A human hair is formed by long flexible horn plates consisting of respectively. 90% α-keratin, a biological polymer and approx. 10% water.
The hair root sits down in the skin of the hair follicle. From the hair follicle, the hair grows at a rate of about 0.3 – 0.4 mm per day.
Man is covered with hair all over the body with few exceptions: lips, palms, soles, scar tissue, parts of the genitals and nipples. The hair strands do not grow at a constant rate. Their growth is characterized by periods of high growth, replaced by periods of sleep.
The outer layer of hair is called cuticle. It consists of flat sheets that lie layered in 6-10 layers. It is this layer that reveals the health of the hair. For healthy hair, the plates lie flat against each other and provide a smooth surface that reflects the light optimally. For unhealthy and dry hair, the plates sprinkle in relation to each other and give the hair a rough and matt appearance.