All that stress in your life—work, family, whatever—so far appears to be unrelated to your going grey. Much as we’d like to blame external burdens on that smattering of salt-hued follicles accumulating around our crowns, research is showing that we are really the cause. Or more aptly, our cells in charge of hair pigment. European scientists recently studied whether an enzyme called catalase, which breaks down hydrogen peroxide in the body, may be the culprit. Low catalase might mean more grey hair because it builds up and blocks melanoma, which gives hair its colour. “Our hair,” explains the New York Times, “bleaches itself from the inside out.” Next, researchers are going to examine how genetics and, of course, stress, may also fit into the grey hair conundrum. Most surprisingly, there’s been no scientific connection found between prematurely greying and ageing. In fact, just the opposite: a Copenhagen study found that people with physical signs of getting old, such grey hair, didn’t die any sooner than others.