Orange pigment may guard cells, solving the puzzle of redheads and orange birds

A CSIC study of 65 zebra finches shows the orange pigment pheomelanin is made from cysteine and can help cells handle excess cysteine, reducing oxidative damage. In males, cysteine supplementation combined with a pheomelanin blocker raised a blood damage marker (malondialdehyde) versus cysteine alone, while females lacking pheomelanin did not show this protective effect, suggesting pigment production helps excrete excess cysteine. The findings offer a cellular rationale for why orange/red coloration persists evolutionarily and imply environment and diet may influence pigmentation-related health risks in humans; researchers plan to explore whether human skin uses a similar cysteine-handling route.