Scientists have found too much stress really does turn our hair white. Researchers discovered that the cells that give hair its color disappears when the body is exposed to stress hormones. Unfortunately for those affected, these ‘colorful' cells are unlikely to return, leaving the hair grey for good. The scientists experimented with mice to find that stress causes the melanocyte stem cells that control skin and hair color to disappear. This could also explain why stress can also cause skin to appear darker.