Which of the following is not a type of melanin found in hair?

The correct answer is phenolic melanin, as it is not a recognized type of melanin found in hair. In the context of hair pigmentation, the two primary types of melanin are eumelanin and pheomelanin. Eumelanin provides dark hues, ranging from black to brown, while pheomelanin contributes to lighter shades, such as yellow and red. Mixed melanin refers to a combination of both eumelanin and pheomelanin, resulting in various hair colors.

The distinction of phenolic melanin lies in its relevance to other biological processes or materials but not in the classification of hair pigments. Understanding these specific types of melanin is crucial in cosmetology, particularly concerning hair coloring and treatment choices, as they directly influence the resulting shades and effects on different hair types.