What produces variation in hair color?

The variation in hair color primarily stems from the types and amounts of pigments produced by melanocytes, which are specialized cells located in the hair follicles. These melanocytes synthesize melanin, the pigment responsible for the color of hair, skin, and eyes. The specific coloration results from the combination of two types of melanin: eumelanin (which can be black or brown) and pheomelanin (which is yellow or red). The genetic information encoded in an individual's DNA determines the quantity and ratio of these pigments produced. This genetic influence explains why hair color can vary widely among different individuals and populations.

While aging and environmental factors may influence the condition of hair or even lead to graying, they do not directly produce the intrinsic variations in color. Similarly, diet and nutrient absorption can have some impact on overall hair health, but they don't specifically dictate hair color variation. UV exposure and chemical treatments might alter existing hair color or introduce temporary changes, but the fundamental nature of hair color variation is rooted in the genetic expression of pigment-producing melanocytes.