What is a biological age test?

A biological age test estimates how old a person's body is functionally, based on measurable biological markers, as distinct from chronological age (years since birth). The most common type is the epigenetic clock, which uses DNA methylation patterns, but functional and blood-based tests also exist.

Are epigenetic age tests accurate?

Epigenetic clocks show strong statistical associations with chronological age and, in newer generations, with mortality and health outcomes across large populations. Accuracy for an individual result is less established, and test-retest variability exists. They are best used as a trend-tracking tool over time rather than a single definitive measurement.

How often should you test biological age?

There is no universally established testing interval. Many people who track biological age retest annually or every 6 to 12 months, ideally using the same test provider each time to reduce measurement variability when comparing results.

Can you lower your biological age?

Some studies suggest interventions like exercise, improved sleep, and dietary changes are associated with more favorable biological age scores on certain tests. Research in this area is still developing, and results vary by test type and study design. No intervention has been established as a reliable, validated way to definitively lower biological age across all testing methods.

Biomarkers

Biological Age Testing Explained

How epigenetic clocks and other biological age tests work, what they can tell you, and where their limits are.

Updated July 9, 2026

Biological age tests attempt to estimate how old a person's body actually is, functionally, as opposed to how many years have passed since birth. The best-known category is the epigenetic clock, but several other testing approaches exist, each measuring a different layer of biological aging.

Epigenetic Clocks

Epigenetic clocks estimate biological age from DNA methylation patterns, chemical modifications to DNA that change in predictable ways over a lifetime without altering the underlying genetic sequence. The first widely used clock, developed by Steve Horvath in 2013, could estimate age from methylation data across many tissue types with strong accuracy. Since then, newer generations of clocks (such as PhenoAge and GrimAge) have been developed to better predict health outcomes and mortality risk, not just chronological age.

First-generation clocks (like Horvath's): trained primarily to predict chronological age accurately.
Second-generation clocks (like PhenoAge, GrimAge): trained to predict health outcomes and mortality risk, which correlate with but are not identical to chronological age prediction.
Third-generation clocks (like DunedinPACE): designed to measure the current pace of aging rather than a single-point-in-time age estimate.

Other Biological Age Testing Approaches

Epigenetic testing is the most marketed approach, but it is not the only one. Other methods used in research and some clinical settings include:

Telomere length testing: measures the protective caps on chromosome ends, which shorten with cell division. Correlates with aging but has weaker individual predictive power than epigenetic clocks.
Composite biomarker panels: combine standard blood markers (inflammatory markers, metabolic markers, kidney and liver function) into a single biological age score using statistical models.
Functional testing: uses physical performance measures like grip strength, VO2 max, and gait speed, which are strongly associated with mortality and disability risk independent of any lab test.
Proteomic and metabolomic clocks: newer research approaches using patterns in blood proteins or metabolites, still primarily used in research settings.

What These Tests Can and Cannot Tell You

Biological age tests are population-level statistical tools applied to an individual. They can identify whether someone's biology, on average, resembles that of an older or younger cohort, and they can track relative change over time within the same person using the same test. What they generally cannot do is provide a precise, individually validated diagnosis or guarantee how a specific intervention will change your personal result.

Important Caveat

Biological age tests are a research and self-monitoring tool, not a diagnostic medical test in the traditional sense, and results should not be used to make treatment decisions without guidance from a qualified healthcare professional. Test-retest variability, differences between commercial testing companies, and the early stage of validation research mean results should be interpreted cautiously.

How to Interpret a Result Responsibly

If you take a biological age test, the most useful approach is to treat the result as a single data point rather than a verdict. Retesting periodically with the same test, alongside functional markers like VO2 max and grip strength, gives a more complete and more reliable picture of trend direction than any single snapshot.

Frequently Asked Questions

What is a biological age test?: A biological age test estimates how old a person's body is functionally, based on measurable biological markers, as distinct from chronological age (years since birth). The most common type is the epigenetic clock, which uses DNA methylation patterns, but functional and blood-based tests also exist.
Are epigenetic age tests accurate?: Epigenetic clocks show strong statistical associations with chronological age and, in newer generations, with mortality and health outcomes across large populations. Accuracy for an individual result is less established, and test-retest variability exists. They are best used as a trend-tracking tool over time rather than a single definitive measurement.
How often should you test biological age?: There is no universally established testing interval. Many people who track biological age retest annually or every 6 to 12 months, ideally using the same test provider each time to reduce measurement variability when comparing results.
Can you lower your biological age?: Some studies suggest interventions like exercise, improved sleep, and dietary changes are associated with more favorable biological age scores on certain tests. Research in this area is still developing, and results vary by test type and study design. No intervention has been established as a reliable, validated way to definitively lower biological age across all testing methods.