What is an epigenetic clock?
An epigenetic clock is a test that estimates how old your body is biologically, rather than in birthdays, by reading chemical marks on your DNA.
Think of your DNA as a book that never changes, and the chemical marks as sticky notes that pile up on certain pages over the years. Count the sticky notes in the right places, and you can estimate how long the book has been in use.
Why it matters for aging
The chemical marks, called DNA methylation, help control which genes are switched on or off. Their pattern shifts with age in predictable ways, so researchers built formulas, the "clocks", that estimate biological age from them. Some, like DunedinPACE, estimate how fast you're aging right now.
Clocks are increasingly used to test longevity interventions quickly, without waiting decades. For example, calorie restriction and omega-3 supplements each slowed some clocks slightly in trials. Commercial tests exist, but they're best seen as rough indicators, not precise measures.
A common myth
An epigenetic clock tells you exactly how long you'll live.
Clocks are useful research tools and predict health risks across large groups, but individual results can vary between tests, and scientists don't yet agree on which clock matters most.
Go deeper
Deep dives
- Omega-3 and aging: what the newest data actually shows
- Does intermittent fasting slow aging? What the trials say
Related terms
Updated Nov 9, 2026 · All terms