haircolor

Hair color refers to the color of human hair, produced by the pigments in hair follicles and modified by light interaction. Natural color is determined mainly by melanin; two forms, eumelanin and pheomelanin, produce a range from black and brown to red and yellow. The balance and distribution of these pigments determine shade and intensity, as well as how hair reflects light.

Natural hair colors span black, brown, blond, and red, with variations such as gray and white arising from aging. Hair can darken or lighten due to sun exposure, hormonal changes, or disease. Graying results from a decline in melanin production and changes in hair structure.

Genetics influence hair color through multiple genes in a polygenic trait. No single gene determines color; small variations and gene interactions shape the spectrum across populations and individuals. Ethnicity and ancestry contribute to typical ranges observed in different groups.

Hair coloring includes products that alter natural pigment. Permanent dyes use oxidative reactions to deposit color and require a developer, while semi-permanent and demi-permanent products fade over time. Bleaching/lightening removes pigment. Professional applications often yield more predictable results and reduce damage, but home kits are common.

Safety and maintenance considerations include patch testing for allergies to dye ingredients, especially p-phenylenediamine. Follow manufacturer instructions to minimize irritation and damage. Color care involves using color-safe shampoos, conditioners, and sun protection to slow fading and maintain vibrancy.

Hair color intersects with fashion, identity, and culture, and varies across history and regions as a cosmetic choice or as a natural trait.