Melanin pigment is a term that is used to describe the color found in most parts of the human body, including the skin and hair. Produced by oxidation of the amino acid tyrosine, followed by polymerization, melanin pigment is created in three types: eumelanin, pheomelanin, and neuromelanin.
There are two kinds of eumalenin: brown and black. Both are responsible for the hair color that people have. When black eumelanin is present where other pigments are not, grey hair forms. Likewise, when brown eumelanin is present where other pigments are not, blonde hair forms. As the body ages, it continues to produce black eumelanin while the production of brown eumelanin gradually slows down. This is why people go gray.
A pink or reddish hue, pheomelanin is often found in the lips, nipples, and genital areas. The color depends on the concentration of the pheomelanin in each area. When brown eumelanin combines with pheomelanin, the result is red hair. Since redheads carry pheomelanin, their skin tends to be pinkish as well.
Although neuromelanin’s function is still unknown, it is a darker pigment that is found in specific areas of the brain. Humans have the largest concentration of neuromelanin; other species have less or even none. It’s thought that this may be the cause of or linked to some brain disorders.
Melanin pigment is essential for humans because it protects the skin from UV rays and UVB radiation. This function becomes obvious when skin or hair pigment changes colors after being in the sun for a while.