As someone with a full head of grey hair, it made me happy to learn that it was just not the result of me getting older. Grey hairs could be the scars left by our bodies’ war against cancer, a new study has found.

Recently published in Nature Cell Biology, the study looked into how the cells responsible for the pigments in our hair and skin ‘self-destruct’ when damaged, as part of our body’s efforts to protect us from cancer.

The scientists found that, under specific types of damage, these pigment-producing cells simply shut themselves down instead of continuing to divide. That choice prevents faulty cells from spreading dangerous mutations – but over time, it also means fewer pigment-making cells remain, causing hair to turn grey.

Scientists have long explored ways to stop pigment cells from self-destructing in an attempt to prevent greying, but the new findings suggest your greys are a sign of an important anti-cancer defense.

The researchers say that understanding – and eventually controlling – this response could open the door to new ways of eliminating high-risk cells before they become cancerous.