What Part of Hair Gives Melanin?
Melanin, the pigment responsible for hair color, is produced by melanocytes located in the upper hair matrix of the anagen hair follicle.
The process begins within the hair follicle itself. Specifically, melanocytes residing in the upper hair matrix, situated below the pre-cortical keratinocytes, are responsible for melanin synthesis. This melanin is then transferred to the hair shaft, primarily to the cortex, with lesser amounts going to the medulla and rarely to the cuticle. The amount and type of melanin produced determine hair color. More melanin leads to darker shades, while less results in lighter colors.
- Melanocytes: Specialized pigment-producing cells.
- Hair Matrix: The actively growing part of the hair follicle.
- Anagen Phase: The growth phase of the hair cycle where melanin production is most active.
- Cortex: The main structural part of the hair shaft.
- Medulla: The central core of the hair shaft (often absent in fine hair).
- Cuticle: The outermost protective layer of the hair shaft.
The cited research emphasizes the localization of melanogenically active melanocytes in the upper hair matrix, directly linking melanin production to this specific area within the hair follicle during the anagen phase. The transfer of melanin from these cells to the hair shaft dictates the resulting hair color. Conditions like vitiligo, where melanocytes die or stop producing melanin, result in loss of pigment and depigmentation of the hair. Conversely, albinism is characterized by little or no melanin production, leading to very light or white hair.
Various types of melanin exist, such as eumelanin (responsible for black and brown hues) and pheomelanin (contributing to red and yellow tones). The relative proportions of these melanin types determine the final hair color. The aging process naturally slows melanin production, leading to graying hair.
