Your chronological age is a fact: the number of years since you were born. Your biological age is an estimate: how old your body appears to be based on measurable molecular markers. Two fifty-year-olds can have meaningfully different biological ages, and that gap predicts who develops age-related disease first.
Biological age tests, built on “epigenetic clocks,” are now available direct to consumers. Here is how the science works, which tests are legitimate, and how to interpret your results without overreading them.
What Epigenetic Clocks Actually Measure
Almost every biological age test on the market measures DNA methylation, chemical tags attached to your DNA that turn genes up or down without changing the genetic code itself. Methylation patterns shift predictably as you age, and machine learning models trained on thousands of samples can estimate age from those patterns with remarkable accuracy.
First-generation clocks (Horvath, Hannum, 2013) predicted chronological age. Second-generation clocks were trained to predict health outcomes: PhenoAge (Morgan Levine, 2018) estimates phenotypic age from methylation patterns linked to clinical biomarkers; GrimAge (2019) predicts time to death, heart disease, and cancer, and is the strongest mortality predictor among the clocks in large cohort studies. Third-generation clocks measure pace of aging: DunedinPACE (Belsky group) estimates how fast you are aging biologically, like a speedometer rather than an odometer. A pace of 1.2 means aging 20 percent faster than average.
Telomere length tests exist too but are noisier and less predictive than methylation clocks, which is why the serious consumer tests focus on methylation.
The Companies Worth Knowing
TruDiagnostic: Most comprehensive consumer option. TruAge uses blood, reports multiple clocks including OMICmAge, DunedinPACE, organ-system aging scores, telomere estimates, inflammation markers. Priciest, reflecting panel depth.
Elysium Index: Developed with Morgan Levine, saliva-based. One biological age number with context. Lower price, less granularity.
myDNAge: From Zymo Research (an epigenetics reagents company), based on Horvath’s clock, blood or urine, around $299.
Tally Health: Co-founded with technology from David Sinclair’s Harvard lab, cheek swabs. Newer, less independently validated.
What to avoid: tests that do not name their clock, and tests bundling an age number with a mandatory supplement subscription claiming to reverse it.
What Changed in 2026
The short answer: A biological age test estimates how old your body looks at the molecular level, usually from DNA methylation patterns. The best-validated consumer options in 2026 pair multiple clocks, GrimAge and PhenoAge for mortality risk, DunedinPACE for your current pace of aging. Expect to pay $249 to $499, and treat any single number as a starting point, not a verdict.
The most important 2026 development is a humility check from the top of the field. The Biomarkers of Aging Consortium, writing in Cell, stated plainly that there are not yet any formally validated or likely surrogate endpoint biomarkers of aging. The US National Institute on Aging frames the new organ-level age tools conditionally: if they can accurately predict future disability and mortality, they could help guide lifestyle changes. Translation: these tests are useful research-grade signals, not medical diagnoses.
The practical shift is that pace-of-aging measures have taken the lead for anyone tracking an intervention. DunedinPACE, which estimates how fast you are aging right now rather than how old you look, has emerged as the 2026 gold standard for before-and-after testing because it responds to change in months rather than years. Organ-specific aging is now standard on the better panels: SYMPHONYAge and NOVOS Age track individual organ system ages, since different body parts age at different rates.
Prices held roughly steady. Here is the 2026 landscape:
| Test | Sample | What it measures | Price |
|---|---|---|---|
| TruDiagnostic TruAge COMPLETE | Finger-prick blood | OMICmAge, SYMPHONYAge, DunedinPACE, 1M+ CpG sites | $499 ($249/yr) |
| NOVOS Age | Finger-prick blood | DunedinPACE, organ ages, telomere estimate | $349 ($299 for 2+) |
| Elysium Index | Saliva | 9 system ages, ~100k markers | $299 |
| Tally Health | Cheek swab | CheekAge (proprietary clock) | $249 |
| GlycanAge | Finger-prick blood | IgG glycans (inflammatory aging) | ~$300-400 |
| InsideTracker InnerAge | Blood draw | Blood-biomarker age | $99 add-on |
| Function Health | Blood draw | 160+ biomarker panel, age as one output | $365/yr |
Two rules from the data. First, blood-based epigenetic tests are the most consistent; saliva and cheek-swab tests vary more, and unvalidated proprietary clocks with no published validation are a dealbreaker when predictive accuracy is the whole point. Second, pair any test with data you can act on: our best DNA test for biohackers guide covers the genetic layer, a CGM for non-diabetics shows your real-time metabolic response, and the best gut microbiome test roundup covers the inflammatory angle most age tests ignore.
How to Interpret Your Results
The key number is the gap between biological and chronological age, or your pace-of-aging score. But calibrate: error margins run a few years either way, and companies use different clocks, sample types, and reference populations. A saliva clock and a blood clock can disagree about the same person. Do not treat any single result as a medical verdict.
What tests are genuinely good for is tracking change over time. Baseline, sustained lifestyle changes, retest in six to twelve months. The trend matters more than any one number. Researchers caution we do not yet know how sensitive these clocks are to short-term changes in individuals.
Which Test Fits You?
Three questions, one recommendation. Answer honestly, the wrong test is an expensive shrug.
1. What is your goal?
For information only, not medical advice. Talk to your doctor before changing anything.
What Actually Moves the Number
No supplement has been shown in rigorous trials to reliably reverse epigenetic age in humans. What observational data links to younger biological age: not smoking (quitting is the highest-leverage change for smokers), regular vigorous exercise, healthy body composition, good sleep, moderate or no alcohol, strong social connections. The CALERIE trial (25% calorie restriction for two years) slowed DunedinPACE aging, though sustained 25% restriction is not practical or necessarily safe advice.
I applied the same standard when I had the peptide evidence compared against the bioregulator research, and neither category has a rigorous human trial behind it.
NAD boosters are the most-marketed example of that gap between promise and proof. If you are deciding between NAD IV or NMN, my comparison lays out what each route costs and what the evidence actually supports.
What Drives Your Biological Age?
Score your habits against the 5 lifestyle drivers research links to epigenetic age.
Should You Take One?
A test makes sense if you are data-driven, will use the result as motivation and a tracking tool, and can afford to retest. Less sense as a one-time curiosity or a medical diagnostic, which it is not. If you test: choose a company that names its clock, uses blood when possible, publishes methodology, no supplement subscription required. Your biological age is not your destiny; it is a summary of where your habits have brought you so far, and habits can change.
Related reading on thebiohack.org: which biohacks actually work and which are a waste of money, why healthspan is the new lifespan, and what aging in large dogs reveals about lifespan biology.
Frequently Asked Questions
How accurate are biological age tests?
It depends on the test. Blood-based epigenetic tests are the most consistent, the same sample run twice gives essentially the same result. Saliva and cheek-swab tests vary more, and cheap tests using unvalidated proprietary algorithms can swing widely. The Biomarkers of Aging Consortium noted in 2026 that no aging biomarker is formally validated as a surrogate endpoint yet, so treat every result as an estimate with error bars, not a lab-grade fact.
What is a good gap between biological and chronological age?
A biological age a few years below your chronological age is a meaningful signal that your habits are working. Gaps of 5 to 10 years are exceptional. A pace-of-aging score like DunedinPACE above 1.0 means aging faster than average and is the number most worth moving. Single-test wobbles of a year or two are usually noise, not news.
How often should I retest?
Once a year is plenty for most people. Pace-of-aging measures like DunedinPACE can show change in months, which makes them the right tool for testing an intervention, but retesting more often than quarterly mostly measures noise and lightens your wallet. Pick a test you will actually repeat.
Can a biological age test tell me if a supplement works?
Only the intervention-sensitive measures can even try. A pace-of-aging score moving down after six months of a real lifestyle change is informative. A single biological-age number bouncing between two tests proves nothing on its own, which is why sellers who bundle a test with a mandatory supplement subscription deserve skepticism.
Are biological age tests worth the money?
If you will act on the result and retest with the same test, the top-tier panels justify their price, TruDiagnostic at $499 for the full workup, NOVOS at $349 for DunedinPACE-based tracking. If this is pure curiosity, buy the cheapest legitimate option, Elysium at $299 or Tally at $249, and spend the savings on the habits that actually move the number.
