Question: which pigment determines the colour of human hair

title: Human skin color
text: The genetic mechanism behind human skin color is mainly regulated by the enzyme tyrosinase , which creates the color of the skin , eyes , and hair shades . Differences in skin color are also attributed to differences in size and distribution of melanosomes in the skin . Melanocytes produce two types of melanin . The most common form of biological melanin is eumelanin , a brown - black polymer of dihydroxyindole carboxylic acids , and their reduced forms . Most are derived from the amino acid tyrosine . Eumelanin is found in hair , areola , and skin , and the hair colors gray , black , blond , and brown . In humans , it is more abundant in people with dark skin . Pheomelanin , a pink to red hue is found in particularly large quantities in red hair , the lips , nipples , glans of the penis , and vagina . 

Answer: answer: Eumelanin, which is behind the colors black , blond , and brown, and Pheomelanin, which is behind the red color, are the two pigments that determine the human hair color.
answer: Eumelanin determines the hair colors gray, black, blond and brown, and Pheomelanin, determines red hair color.