Melanin in the skin
Melanin is the brownish to black color pigment in the human skin. There it is produced in certain cells, the so-called melanocytes. The production of melanin is stimulated by the UV rays in the sun and by a hormone produced by the body itself.
There are two different forms of melanin in the skin. Pheo and eumelanin determine the skin color of the respective person due to their content. In light-skinned skin types, there is a higher proportion of phenomelanin in the skin.
Darker skin and hair types have less phenomelanin in the skin. In the skin, melanin plays an important role. It is produced under the influence of sunlight or from precursors and is stored in certain cells of the skin, the keratinocytes.
Melanin is like a protective coat around the nuclei of the skin cells. In this way the nuclei of the cells are protected from the dangerous rays. They contain the information of the genetic material that can be damaged by the rays and promote the development of cancer cells.
If melanin is missing in the skin due to a genetic defect or a disturbance in production, the affected persons have very light skin. This then affects all pigment-containing cells as well as the hair and eyes. The appearance is known as albinism.
On the other hand, overproduction of melanin can also occur. The skin then shows an increased number of brown spots of different sizes. These can be moles, birthmarks and freckles. These skin changes also increase the risk that they degenerate and lead to skin cancer (malignant melanoma).
Melanin in the hair
Which hair color a person has depends mainly on genetic factors and the melanin content in the hair cells. The ratio of Eu- and phaeomelanin determines the hair color.Eumelanin contains much black-brown pigment, while pheomelanin contains much red pigment. Accordingly, lighter hair types have little eumelanin and much pheomelanin.
Darker hair types have exactly the opposite ratio. Red-haired people, like blond hair types, have very little eumelanin and even more of the pheomelanin. The individual mixture of these different pigments creates different hair colors, which can also combine different colors. The melanin determines the hair color, but is not responsible for the hair structure. Grey hair is caused by the loss of the melanin content in the cells.
