Biologists call our hair "skin appendages" (Adnexa). The millions of hairs and tiny hairs are much more than merely appendages. Hair helps to protect our skin and our body. Our scalp hair, for example, ensures that the scalp is protected against sunburn. Hair also regulate our body temperature: when it is cold, they prevent heat loss, and at high and hot temperatures they have a cooling effect. Our eyebrows and eyelashes protect the eyes from foreign particles and drops of sweat, and nasal hairs are our protection against poor air, a bit like a catalytic converter that filters the air before it reaches the lungs. These are all functions that nature has developed for us over millions of years of evolution. Even if the density of body hair has decreased significantly over the course of evolution. 

But hair is also important for the soul, our self-confidence and personal satisfaction. Whether it's the right hairstyle, a cool beard or breathtaking eyelashes: Hair adorns us and makes us look good. After all, hair is able to grow on a good 96% of the skin's surface. Only our hands, lips, the soles of our feet, fingernails and toenails are completely hairless. 

Anyone involved in the subject of hair care has probably stumbled across many names, technical terms and explanations about hair and its structure. Hair is basically long protein filaments that protrude from the skin. They consist of up to 95% of the protein keratin. This substance is also found in our nails. The same is found in the animal kingdom, for example in the beaks of birds or a rhinoceros horn.