DNAm PhenoAge is an epigenetic clock that estimates biological age from DNA methylation patterns measured in blood. DNA methylation involves the addition of methyl groups to cytosine bases at specific sites across the genome, and these patterns change in a predictable, age-related way. DNAm PhenoAge was developed by Dr Morgan Levine and colleagues at Yale University using methylation data from thousands of individuals, trained to predict a composite measure of biological age derived from clinical biomarkers.

Unlike biological age estimates based on blood chemistry panels, DNAm PhenoAge reads the epigenetic state of the genome directly, providing a measure that is closer to the cellular ageing process itself. A DNAm PhenoAge lower than chronological age suggests the cellular environment is ageing more slowly than average; a higher epigenetic age indicates cellular ageing is accelerated and is predictive of increased all-cause mortality, disease risk, and reduced healthspan.