The brown or black pigment that gives skin, hair, and the iris of the eyes their colouring. Melanin is produced by cells called melanocytes. Exposure to sunlight increases the production of melanin, which protects the skin from the harmful effects of ultraviolet rays and causes the skin to darken. Localized overproduction of melanin in the skin can result in a pigmented spot, most commonly a freckle or mole (see naevus).
Melanin |
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