EvidenceBModerateGood evidence in people with one real weakness. New studies could change the answer.
Epigenetic age tests read chemical tags on your DNA, mostly from blood, and turn them into an "age" estimate. That estimate predicts risk of death and disease, but whether it measures aging itself is unproven.
Who it's for
Researchers tracking groups of people; not shown to guide personal health decisions.
What to expect
A number linked to future illness and death risk, not a diagnosis.
Watch out for
Different tests give different results, and none is proven to track true aging.
Figure 2. Univariate Cox regression meta-analysis of all-cause mortality A univariate Cox regression model was used to relate the censored survival time (time to all-cause mortality) to (A)…
An expert consensus statement of 60 panel members in the final voting round included DNA methylation (epigenetic) clocks among 14 biomarkers A measurable sign in the body, like a blood test result, used as a stand-in for health outcomes that take longer to appear. that may be used as outcome measures in studies of anti-aging interventions. The panel said further research should show which combination of biomarkers is most useful7Guideline · 2025An Expert Consensus Statement on Biomarkers of Aging for Use in Intervention Studies.Expert consensus identified 14 potential biomarkers of aging which may be used as outcome measures in intervention studies. Future aging research should identify which combination of these biomarkers has the greatest utility.J Gerontol A Biol Sci Med Sci.
What the studies show
A pooled analysis of 13 groups with 13,089 people found that older-looking epigenetic age was linked to earlier death. This held after accounting for actual age and usual risk factors, and across three racial and ethnic groups3Meta-analysis · 2016 · 13,089 peopleDNA methylation-based measures of biological age: meta-analysis predicting time to death.5x10-43). Overall, this study a) strengthens the evidence that epigenetic age predicts all-cause mortality above and beyond chronological age and traditional risk factors, and b) demonstrates that epigenetic age estimates that incorporate information on blood cell counts lead to highly significant associations with…Aging (Albany NY). These figures compare groups, so the meaning for one person depends on their starting risk.
A reviewed set of 156 publications found four widely used clocks (Horvath, Hannum, Levine and GrimAge) tend to agree in direction but differ in size. Faster clock ageing was linked to higher body mass index, HIV infection, male sex, death, heart disease, cancer and diabetes5Systematic review · 2021A systematic review of biological, social and environmental factors associated with epigenetic clock acceleration.Acceleration of epigenetic clocks was also significantly related to mortality, cardiovascular disease, cancer and diabetes. Our findings provide a graphical and numerical synopsis of the past decade of epigenetic age estimation research and indicate areas where further attention could be focused in the coming years.Ageing Res Rev.
GrimAge, built from DNA-based estimates of blood proteins and smoking, was the strongest predictor of time to death, heart disease and cancer among the clocks compared. These are associations in observational Studies that watch what happens to people rather than assigning a treatment. They can show links, not cause and effect. data8Observational study · 2019DNA methylation GrimAge strongly predicts lifespan and healthspan.These DNAm-based biomarkers show the expected relationship with lifestyle factors including healthy diet and educational attainment. Overall, these epigenetic biomarkers are expected to find many applications including human anti-aging studies.Aging (Albany NY).
DunedinPoAm was built from 12 years of change in 18 body-health markers in 954 people born in 1972-1973. It aims to measure how fast someone is aging at one point in time9Observational study · 2020 · 954 peopleQuantification of the pace of biological aging in humans through a blood test, the DunedinPoAm DNA methylation algorithm.Elastic-net regression was used to develop a DNA-methylation predictor of Pace-of-Aging, called DunedinPoAm for Dunedin(P)ace(o)f(A)ging(m)ethylation. Validation analysis in cohort studies and the CALERIE trial provide proof-of-principle for DunedinPoAm as a single-time-point measure of a person's pace of biological…Elife.
A pooled analysis of longitudinal cohorts (up to 1,054 people per cohort) found epigenetic age rose more slowly than actual age, especially in the oldest. Part of this may reflect healthier people staying in studies. The same person's readings across time agreed only partly2Meta-analysis · 2019 · 1,054 peopleTracking the Epigenetic Clock Across the Human Life Course: A Meta-analysis of Longitudinal Cohort Data.Epigenetic age increases at a slower rate than chronological age across the life course, especially in the oldest population. Some of the effect is likely driven by survival bias, where healthy individuals are those maintained within a longitudinal study, although other factors like the age distribution of the…J Gerontol A Biol Sci Med Sci.
Blood-test-based measures of biological age (such as PhenoAge) have outperformed methylation clocks at predicting healthy lifespan in several studies6Randomized trial · 2021A toolkit for quantification of biological age from blood chemistry and organ function test data: BioAge.Results contribute evidence that CALERIE intervention slowed biological aging. BioAge is a toolkit to facilitate measurement of biological age for geroscience.Geroscience. A systematic review A review that searches for every study on a question in a set way and weighs them together, rather than picking a few. of 33 clocks reported that methylation clocks predict chronological age very well4Systematic review · 2024A systematic review of phenotypic and epigenetic clocks used for aging and mortality quantification in humans.We also reported the most influential clinical measurements used in the included phenotypic clocks. Our findings provide a systematic reporting of the last decade of biological clock research and indicate possible avenues for future research.Aging (Albany NY).
Key studies
Study
Who
What it found
Pooled analysis of 13 cohorts, 20163Meta-analysis · 2016 · 13,089 peopleDNA methylation-based measures of biological age: meta-analysis predicting time to death.5x10-43). Overall, this study a) strengthens the evidence that epigenetic age predicts all-cause mortality above and beyond chronological age and traditional risk factors, and b) demonstrates that epigenetic age estimates that incorporate information on blood cell counts lead to highly significant associations with…Aging (Albany NY)
13,089 people
Higher epigenetic age predicted earlier death beyond usual risk factors
Review of 156 publications, 20215Systematic review · 2021A systematic review of biological, social and environmental factors associated with epigenetic clock acceleration.Acceleration of epigenetic clocks was also significantly related to mortality, cardiovascular disease, cancer and diabetes. Our findings provide a graphical and numerical synopsis of the past decade of epigenetic age estimation research and indicate areas where further attention could be focused in the coming years.Ageing Res Rev
Blood-based clock studies
Clocks agree in direction; linked to disease and death
Cohort study Researchers follow a group of people over time without giving them a treatment. It can show links, not cause and effect., 20198Observational study · 2019DNA methylation GrimAge strongly predicts lifespan and healthspan.These DNAm-based biomarkers show the expected relationship with lifestyle factors including healthy diet and educational attainment. Overall, these epigenetic biomarkers are expected to find many applications including human anti-aging studies.Aging (Albany NY)
Thousands of adults
GrimAge predicted death, heart disease and cancer best
Cohort study, 20209Observational study · 2020 · 954 peopleQuantification of the pace of biological aging in humans through a blood test, the DunedinPoAm DNA methylation algorithm.Elastic-net regression was used to develop a DNA-methylation predictor of Pace-of-Aging, called DunedinPoAm for Dunedin(P)ace(o)f(A)ging(m)ethylation. Validation analysis in cohort studies and the CALERIE trial provide proof-of-principle for DunedinPoAm as a single-time-point measure of a person's pace of biological…Elife
954 people followed 12 years
DunedinPoAm estimates pace of aging from one blood sample
Pooled longitudinal analysis, 20192Meta-analysis · 2019 · 1,054 peopleTracking the Epigenetic Clock Across the Human Life Course: A Meta-analysis of Longitudinal Cohort Data.Epigenetic age increases at a slower rate than chronological age across the life course, especially in the oldest population. Some of the effect is likely driven by survival bias, where healthy individuals are those maintained within a longitudinal study, although other factors like the age distribution of the…J Gerontol A Biol Sci Med Sci
Up to 1,054 per cohort
Readings change over time; agreement between visits varied
What we don't know
Whether a clock changes because a person is truly aging more slowly, or only because of other factors such as blood cell makeup.
Whether lowering a clock reading through lifestyle or treatment lowers a person's actual risk.
Written by AI from the studies listed, without review by a clinician, and graded with the GRADE method. It can be wrong, so check the studies it cites. Education, not medical advice.