The EBL Longevity Biological Test
A small, deliberately curated set of biological-age markers, not a kitchen-sink panel. This is the standard measurement we use to set a baseline before an intervention protocol and to re-check it afterward. We include only markers that clear two bars at once: strong human-outcome validation, and reliable enough to track a real change in one person over a few months.
Why we keep it focused
A comprehensive panel has real value. A deep baseline with many reports, organ-system ages, and a wide biomarker A measurable sign in the body, such as a blood test value, used to track a condition or the effect of a treatment. set gives you a rich first picture of where you stand, and the better labs build genuinely sophisticated tools for exactly that. We are not arguing against that.
Our purpose here is narrower. We are tracking whether one specific protocol moved your aging over a few months. For that job you do not need the full suite every time. You need a small set of markers that are well validated and stable enough that a before-and-after comparison is trustworthy, run consistently each time. Keeping the tracking panel focused also keeps the repeat cost down, which matters when you are testing more than once. The leading labs agree with this split: TruDiagnostic, for instance, sells a dedicated pace-of-aging tracking kit precisely for re-checking after an intervention, separate from its full baseline collection.
DunedinPACE measures how fast you are aging, which is the thing an intervention is built to change, so it responds where a one-time age estimate may not.
DunedinPACE test-retest reliability. Among the most stable aging measures available, which is why it leads our tracking panel.
A focused tracking kit costs less than a full baseline collection, so re-testing after a protocol stays affordable.
In their raw form, first-generation clocks can swing by several years between two samples drawn from the same person at the same time, purely from technical variation in how the array is run. When that swing is as large as the change you are trying to detect, the reading is hard to act on at the individual level. The strongest panels address this directly, by recalculating their clocks with principal components and by centering the pace-of-aging measure, DunedinPACE. Those are the same reliable forms we build our panel around.
The markers
DunedinPACE
Pace of aging. How fast you are aging right now, where 1.0 is one biological year per calendar year. Unlike a biological-age estimate, which is a snapshot, DunedinPACE measures the rate of aging, which is what an intervention is trying to change. It has the strongest reliability of any marker here and validated associations with morbidity and mortality. For tracking whether a protocol worked, this is the number we weight most. Belsky et al., eLife 2022, PMID PubMed ID: the permanent number the US National Library of Medicine gives a published paper. Each one links to that paper's record on PubMed. 35029144.
Biological age
The familiar "your biological age is X" number, from a current-generation, mortality-validated clock. Through TruDiagnostic this is OMICmAge, developed with Harvard. We use the principal-component form rather than a raw clock, because the raw version is too noisy for individual tracking. This gives a single intuitive figure with real mortality validation behind it. Levine et al., Aging 2018, PMID 29676998; reliability method from Higgins-Chen et al., Nature Aging 2022, PMID 36277076. Read these with the conflict of interest in view: epigenetic clock A test that estimates biological age from chemical marks on DNA (DNA methylation). research in this space is frequently vendor-authored, including work co-authored by TruDiagnostic staff or run on TruDiagnostic assays.; reliability method from Higgins-Chen et al., Nature Aging 2022, PMID 36277076.
Telomere length
A classic hallmark of aging, included for context and read with the most caution. We are honest that this is the weakest marker for tracking one person over a short window. It is a well-known aging hallmark, but it is variable and a noisy individual-level predictor. We use the DNA-methylation estimate of telomere length so it comes from the same sample as the other markers, rather than a separate assay. Treat movement here as supporting context, not as a result on its own. Lu et al., Aging 2019.
Immune aging readout
A measure of immune-system aging, such as a methylation-derived immune cell profile, can be added from the same sample. It is optional rather than core, kept off the default panel to hold the line on staying focused. EBL rates a marker on how reliably it moves before and after an intervention, and that evidence is not yet in hand for this one. It is reported because it comes from the same sample at no extra draw, not because it carries a confidence rating.
How to source it
All of these markers are computed from a single DNA methylation reading, so one finger-prick blood spot or saliva sample produces the whole panel. That keeps the readings internally consistent, since they come from the same run rather than being stitched together across labs. DunedinPACE, the marker we lead with, is exclusively licensed to TruDiagnostic, so that is where the panel is sourced. Their two kits map directly onto the baseline-and-retest model.
TruAge PACE
DunedinPACE plus the telomere length report. The lower-cost of the two kits. It reports EBL's two core tracking markers.
TruAge COMPLETE
Adds the OMICmAge biological-age clock and immune-system aging, so it reports all four EBL markers.
The baseline-and-retest model depends on the same marker being measured both times. PACE reports the two tracking markers; COMPLETE reports all four. Cost is set by the seller, not by EBL.
EBL has an affiliate relationship with TruDiagnostic. That relationship does not change any grade on this platform. The panel appears here because it reports DunedinPACE from a single draw, which is what makes intervention tracking possible.
How it is used with an intervention
Baseline: before any protocol in the Measurable Interventions section begins. A duplicate baseline sample shows a person's own measurement spread.
Because it is the most reliable and most responsive marker, weight it most when judging whether a protocol moved the needle. The biological-age number is the intuitive headline. The pace number is the one to trust for change.
A re-test is comparable only at the protocol's stated interval, with the same provider, sample type and conditions. Consistency is what makes the comparison valid.
For short protocols, do not re-test more often than every few months. For year-long patterns, annual is sensible. Testing too often just samples noise.
What the measurement can resolve
A 2025 review in Epigenomics assembled the reliability data across the epigenetic clocks now sold direct to consumers. Its numbers set the floor on how small a change any of these tests is capable of detecting, and they are reproduced here in full rather than summarized, because the size of the measurement spread is the whole point.
Intraclass correlation across clocks ranges from 0.86 to 0.99, with coefficients of variation of 2% to 10%. The upper end of that range belongs to pace-of-aging measures. First-generation age-estimate clocks sit at the lower end, which is the reason DunedinPACE leads the panel above rather than a biological-age number.
The same DNA sample, split and run twice, has produced biological-age estimates differing by up to 9 years. Nothing about the person changed between those two readings.
First-generation clocks show a median absolute error of at least 3.6 years against known chronological age. The review states directly that a difference of a year or two between two readings “may fall within the margin of error.”
One measurement in isolation is characterized as “more likely to reflect a weak and noisy signal” than a stable property of the person being measured.
The consequence is arithmetical rather than editorial. Where a repeated measurement of an unchanged sample can move by several years, a difference between two timepoints that is smaller than that spread does not establish that anything changed. This is why the panel above is built around the most reliable marker instead of the most intuitive one, and why the duplicate baseline sample is listed alongside the first draw.
What the clocks are, in the review’s own terms
The same authors characterize clock output as “probabilistic information derived from group-level associations, not mechanistic insight,” and record that no individual-level evidence demonstrates that changing a clock reading improves any health outcome. Their conclusion is quoted rather than paraphrased:
“applying epigenetic clocks in individual-level decision making can be uninformative and potentially harmful”
The review also records that these metrics have already moved past wellness use: FOXO Technologies integrated epigenetic aging measures into life-insurance underwriting in 2023.
EBL lists this panel because a curated, reliability-weighted set of markers is a better instrument than a kitchen-sink one, and because the interventions section needs some readout to be measurable against. That case is unchanged by the numbers above. What the numbers change is the size of a difference that means anything, and the weight a single result can carry on its own.
Honest limits
Every marker here is a surrogate. A better reading is associated with better outcomes in population data, but no result on this test proves years added to your life. Published intervention effects are group medians. Your individual reading is a single noisy data point, which is exactly why the panel is curated for reliability and why DunedinPACE leads it. This test is educational and is not a diagnostic or a substitute for clinical care.
Human-trial evidence only. Grades A to D. Last reviewed: June 2026. This page is educational and is not medical advice. Biological-age markers are surrogate measures, not a measure of remaining lifespan. The EBL Longevity Biological Test is distinct from the EBL Longevity Lab Panel and the Hormone Panel. Edited by EBL Editorial.