What is an epigenetic clock?

An epigenetic clock is a type of biochemical test that indicates biological age using DNA methylation levels. These clocks are based on DNA methylation at specific sites in the genome, particularly at CpG sites where a cytosine nucleotide is followed by a guanine nucleotide. Changes in methylation at these sites, as observed in DNA, can tell us about an individual's age biologically, which can be different from their chronological age.

Epigenetic clocks can predict biological age by determining patterns of DNA methylation that correlate with age, suggesting how old a person seems biologically compared to their actual age. These clocks are potentially important for studying aging, estimating disease risk, predicting life expectancy, and evaluating anti-aging treatments [1].