The role of melanin in hair pigmentation
Melanin, the pigment responsible for hair and skin color, exists in two forms: eumelanin, which produces shades of brown to black, and pheomelanin, responsible for shades of red to blond. Produced by melanocytes in the hair follicle, this melanin is then incorporated into the hair fiber as it grows.
Each hair thus appears as a unique mixture of pigments. Over time, however, melanocyte activity slows down and melanin production gradually decreases. This natural process explains the loss of color and the gradual appearance of gray hair.
What factors influence the loss of pigmentation?
Two types of factors can be involved: internal factors, mainly related to age, and external factors, related to lifestyle and the environment. According to some recent studies, these external factors could even cause temporary hair discoloration.
However, aging remains the main driver of pigment loss. Over time, melanocytes decrease in number and effectiveness: they produce less melanin, which gradually makes the hair lighter.
Other factors can accelerate this phenomenon. Oxidative stress, linked in particular to sun exposure, pollution, or repeated use of harsh hair products, can weaken the defense mechanisms of hair cells. The often-cited link between stress and the appearance of gray hair is therefore no coincidence: when natural defenses weaken, pigmentation can decline more rapidly.
For more information, you can also consult our article What causes gray hair?





















