Comparison

GrimAge vs PhenoAge vs DunedinPACE

Last updated 2026-07-02· Last reviewed 2026-07-02· 1 min read

Reviewed by the Ultimate Longevity Bible editorial team. Educational reference — not medical advice. See disclaimer.

What each clock measures

Horvath 2013 (original): chronological age from methylation; not specific to health outcomes.
PhenoAge: methylation-based estimator of biomarker-derived biological age; mortality prediction.
GrimAge: methylation-based estimator of plasma proteins + smoking-pack-years, trained on time-to-death; strong mortality prediction.
DunedinPACE: methylation-based estimator of how fast a person is aging now — trained on the Dunedin cohort's longitudinal decline in 19 markers.

Mortality-risk stratification: GrimAge.
Overall biological age: PhenoAge or GrimAge.
Intervention monitoring ("did this rapamycin protocol slow my aging pace?"): DunedinPACE.
Research on aging biology: often all three, plus original Horvath.

Assay noise is meaningful; single measurements should be interpreted cautiously.
Trend over multiple measurements is more informative than a single time-point.
Not clinically validated for treatment decisions.