Melanin is found in many parts of the body, including the brain, eyes, ears and skin. The exact function of melanin in many of these locations is unknown, but doctors do know that melanin is the pigment that gives hair and eyes their color. Doctors also have a good understanding of how melanin works in the skin, which is crucial as it protects us from the harmful effects of the sun.
Ultraviolet light is a form of radiation, and radiation’s energy does not dissipate unless it is absorbed by another substance. The melanin in human skin is a pigment capable of absorbing these harmful rays and, in doing so, protects the skin from the sun’s ultraviolet light. There is a limit, however, to the amount of energy that melanin can absorb. The melanin becomes darker as it absorbs the energy from the ultraviolet light, causing the darkening of the skin known as a suntan. Sunburn occurs when the amount of ultraviolet light that your skin is exposed to exceeds your melanin’s capacity to absorb it. People with darker skin naturally have more melanin in their skin than those with fair complexions as the natural result of evolution, because some parts of the globe are exposed to more sunlight than others.