In the human body, melanin is the pigment that primarily determines skin, hair, and eye colour.
Melanin is produced by specialized cells called melanocytes. These cells make the pigment inside organelles called melanosomes and transfer the melanosomes to nearby skin cells. The amount, type, and distribution of melanin influence visible pigmentation, while genetics controls much of this variation.
The two main forms in human pigmentation are eumelanin, which is brown or black, and pheomelanin, which is yellow or reddish. Melanin also absorbs ultraviolet radiation, helping protect cellular DNA from some sun damage, although it does not replace sunscreen or other protection. Keratin is a structural protein found in hair and the outer skin, so it is sometimes confused with melanin. Hair appears grey when pigment production decreases.