A substance called melitane works inside hair follicles to kickstart the process that creates color, which brings back the hair's original pigment.

Your hair needs energy from tiny power plants in cells (called mitochondria) to keep making pigment — without healthy mitochondria, your hair can't stay colored over time.

When mouse hair starts growing, pigment stem cells in the hair germ turn on color-making and branch-related genes before they divide.

Too much oxidative stress might lead to fewer pigment-producing cells in hair and cause hair to lose color, based on lab studies that simulate this stress in human hair follicles.

Your hair color depends on special stem cells in your hair roots, and long-term stress from inflammation or oxidation can mess them up, making them disappear or mature too soon.

When your hair grows fast, it might stress the cells that give hair its color, causing them to wear out faster and turn hair gray sooner.