Stress can turn your hair gray by messing with nerve signals in your hair follicles, which damages the cells that give hair its color — and once they're gone, the graying is permanent.

Going gray might happen because the stem cells that keep your hair colored aren't working properly as you age.

Going gray might happen because the stem cells that give rise to hair color cells get damaged over time, not because the color-making cells themselves stop working. Keeping these stem cells healthy could be key to keeping your hair colored as you age.

Your hair color comes from cells in your hair roots, and as you age, those cells slow down — that's why hair turns gray. But new research says things like stress might also play a role.

Stress might be turning your hair gray by messing with your cells, and relaxing could help your hair get its color back.

Going gray might happen because the stem cells that keep your hair colored stop working properly as you age, according to studies in people and specially tagged mice.