Though the legend is inaccurate — hair that has already grown out of the follicle does not change color — a new study from researchers at Columbia University Vagelos College of Physicians and Surgeons is the first to offer quantitative evidence linking psychological stress to graying hair in people.
And while it may seem intuitive that stress can accelerate graying, the researchers were surprised to discover that hair color can be restored when stress is eliminated, a finding that contrasts with a recent study in mice that suggested that stressed-induced gray hairs are permanent.