Epigenetic Clocks

The definitive guide to DNA methylation testing for longevity.

Epigenetic clocks measure DNA methylation—the addition of methyl groups to CpG dinucleotides. As we age, these methylation patterns predictably drift. However, not all clocks are designed to measure the same thing.

Generations of Clocks

1st Generation (e.g., Horvath, Hannum)

Trained to predict chronological age. This means a perfect 1st generation clock would exactly match your driver's license. They are useless for testing anti-aging interventions because they explicitly try to ignore biological variance.

2nd Generation (e.g., GrimAge, PhenoAge)

Trained to predict mortality or time-to-disease. GrimAge remains one of the best predictors of lifespan, heavily weighted by smoking history and protein proxies.

3rd Generation (e.g., DunedinPACE)

Trained to predict the pace of aging. Instead of giving an absolute age (e.g., "you are 45"), they give a rate (e.g., "you are aging at 0.85 biological years per chronological year"). This makes them highly responsive to interventions.

Testing Protocols

We recommend testing baseline before any intervention (e.g., starting Rapamycin or Metformin), and retesting at 6-month intervals. The DunedinPACE algorithm (via TruDiagnostic) is currently the standard for tracking short-term changes.

Common Mistakes

• Using a 1st Gen clock to validate a diet.
• Testing too frequently (less than 3 months apart).
• Comparing results across different test providers (algorithms vary wildly).

FAQ