Longevity & Aging
Can DNA "clocks" measure how fast you're really ageing?
The claim, precisely: epigenetic clocks correlates with biological age
Probably modestly yes for predicting age, but it's only a correlation, not proof they track true biological ageing.
Evidence ladder
How far up the ladder this claim has climbed. A high consensus on a low rung means "consistent so far," not "proven in people."
Top evidence so far: Population patterns (Observational)
How the studies fall
What the evidence shows
DNA-methylation clocks (Horvath 2013) predict chronological age accurately, but they are CORRELATIVE biomarkers - clock movement does NOT equal proven rejuvenation or lifespan gain (Teschendorff 2025; clock signal is partly stochastic drift).
The evidence (12)
| Source | Grade | Stance | Quality | Finding |
|---|---|---|---|---|
| Li 2025 · EBioMedicine | observational | mixed | moderate | CpG-site clocks limited in biological interpretability; pathway-level clock (PathwayAge) needed for disease-specific aging mechanisms |
| Teschendorff 2025 · Nat Rev Genet | observational | mixed | high | Review: clocks are robust age predictors but clock change does NOT equal proven rejuvenation or lifespan benefit |
| Ashapkin 2019 · Adv Exp Med Biol | mechanism | mixed | moderate | Review questions whether clock is convenient marker vs active driver of aging; much age-methylation is stochastic at repeats |
| Ibanez-Cabellos 2026 · Biogerontology | observational | mixed | moderate | Review: clocks robust age estimators but cautions on causal interpretation and clinical readiness for personalized aging |
| Li 2021 · EBioMedicine | observational | supports | high | ESTHER cohort: GrimAge/PhenoAge acceleration independently predict all-cause mortality, validating clocks as biological-age biomarkers |
| Bertucci-Richter 2024 · Aging (Albany) | mechanism | mixed | moderate | Clock signal driven by stochastic methylation disorder; clocks & true aging processes are decoupled - caution against treating clock as causal readout |
| Mitteldorf 2025 · Aging (Albany NY) | observational | contradicts | moderate | Argues methylation clocks unreliable for evaluating anti-aging interventions; methylation under selection, clock change need not mean rejuvenation |
| Ying 2025 · Nature Aging | observational | contradicts | high | Curation framework: ability to predict chronological age does NOT correlate with predicting mortality/outcomes; decouples prediction from biological aging |
| Horvath 2013 · Genome Biol | observational | supports | high | Multi-tissue 353-CpG clock predicts chronological age accurately across human tissues - landmark biomarker, but correlation not causation ⚠️ correction-on-file (Crossref) - kept, corrigendum not retraction |
| Levine 2018 · Aging (Albany NY) | observational | supports | high | 2nd-gen DNAmPhenoAge built on clinical phenotype outperforms 1st-gen clocks at predicting mortality/healthspan across cohorts |
| Tan 2026 · Clinical Epigenetics | observational | mixed | moderate | Later-gen clocks (GrimAge/PhenoAge) predict breast-cancer survival better than Horvath/Hannum; first-gen age-predictors weakly prognostic |
| Hannum 2013 · Molecular Cell | observational | supports | high | Landmark blood methylome model predicts chronological age (~96% correlation, ~3.9yr error); established methylation-age clock concept |
Educational only, not medical advice. Grades and scores reflect published evidence weighted by study design and quality; see the methodology.