Hair | Dark

: Most individuals with dark hair possess two functional copies of the MC1Rcap M cap C 1 cap R

gene, which signals melanocytes to produce eumelanin instead of pheomelanin. dark hair

The Biology and Perception of Dark Hair Dark hair—encompassing shades from deep brown to jet black—is the most prevalent hair color globally, appearing in approximately 90% of the human population. This dominance is the result of specific genetic pathways, biochemical processes, and evolutionary adaptations that have favored the production of dense pigments. Genetic and Biochemical Foundations : Most individuals with dark hair possess two

: Pigment synthesis begins with the amino acid L-tyrosine , which is converted by the enzyme tyrosinase into dopaquinone. In the absence of high sulfur levels (cysteine), this precursor polymerizes into the dark eumelanin. Evolutionary Context dark hair

: Dark hair results from high levels of eumelanin produced by melanocytes in the hair follicle bulb.