Human hair color

Topic

Human hair color is the pigmentation of human hair follicles and shafts, determined primarily by two types of melanin: eumelanin and pheomelanin. Generally, higher levels of melanin result in darker hair, while the specific tone depends on the ratio of black or brown eumelanin to yellow or red pheomelanin. Melanin levels can vary over time, causing a person's hair color to change naturally or gray with age.