Over the past decade, several epigenetic clocks have been developed to track physiological aging. Until recently, all had been based on the DNA methylome of blood cells – onerous and stressful to collect. But now, scientists from the US have shown for the first time that their new epigenetic clock CheekAge, which uses easy-to-collect cheek cells, can accurately predict mortality. This suggests that cheek swabs could be an improved way to measure and predict healthy vs unhealthy aging and mortality in humans.