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More on Longevity
What Is Biological Age, and How Does Testing Work?
What a biological age test can and cannot tell you, how methylation and glycan tests differ, and how people use a baseline and a retest to check whether a routine is working.
A biological age test estimates how your body is aging from molecular markers, rather than counting birthdays. The two main at-home methods are epigenetic testing, which reads DNA methylation patterns, and glycan testing, which reads sugars attached to your antibodies. Both use a finger-prick sample, and both are estimates built for tracking change over time, not medical diagnoses.
Biological age is the measurement layer of a longevity routine. Every device and habit on this site is a bet that something can change, and a test is how you check whether it did. This guide covers how the tests work, where the limits sit, and how our tests differ.
What is biological age?
Chronological age is the number of years you have been alive. Biological age is an estimate of how old your body seems, based on measurable biology. Two people born the same year can carry very different molecular profiles, shaped by genetics, sleep, training, stress, smoking history, and environment. A biological age test compresses some slice of that biology into a number you can compare against your calendar age, and more usefully, against your own previous result.
What is the difference between biological age and chronological age?
The gap between the two has its own name, age acceleration, and its own set of limits, covered in biological age versus chronological age.
Chronological age only moves forward, at exactly one year per year. Biological age estimates can move in both directions, and that is the whole point of testing. The number itself matters less than most people expect. A result of 34 against a calendar age of 38 is encouraging, but the useful signal is the trend across two or three tests taken months apart under similar conditions.
How do biological age tests work?
Epigenetic testing, or DNA methylation
Your DNA sequence does not change with age, but the chemical tags attached to it do. Methylation marks accumulate and shift in patterns that track with aging closely enough that researchers have trained algorithms, usually called clocks, to estimate age from them. First-generation clocks were trained to predict calendar age. Newer generations were trained against health outcomes and against the pace of decline in long-running cohort studies, which makes them more useful for the question people have: how fast am I aging right now? The three generations of clocks, and what each was trained to predict, are unpacked in DNA methylation testing.
The TruAge Epigenetic Test we offer reports three of these: OMICmAge, an age estimate trained against clinical outcomes, SymphonyAge, which breaks the estimate down across 11 organ systems, and DunedinPACE, which reports a pace of aging instead of an age. The analysis runs on a finger-prick blood spot in a CLIA-certified lab.
Glycan testing
The GlycanAge test reads a different layer: the sugar structures attached to your IgG antibodies. These glycans shift with age and with inflammatory state, and they respond to lifestyle change on a timescale of months. Glycan testing reflects the inflammatory side of aging in a way methylation does not, which is why some people run both and treat them as different instruments, not competitors. The two methods are compared side by side in epigenetic versus glycan testing.
How do you test your biological age?
At home, with a mail-in finger-prick kit. You order the test, collect a few drops of blood on a card, post it back in the prepaid mailer, and read the results online two to four weeks later. No clinic visit, no fasting, no blood draw. A certified lab runs the analysis and an algorithm turns it into an age estimate and, on the better tests, a pace of aging.
There are three routes to a number, and they are not equal.
- Mail-in epigenetic or glycan kit. The method behind the tests on this page and the one with a research base behind it: finger-prick blood spot, certified lab, outcome-trained algorithm. $499 for our kits.
- Blood-biomarker calculators. Some published clocks, PhenoAge is the best known, estimate biological age from a standard blood panel: glucose, CRP, albumin, white cell counts and a handful of others. Cheaper if you already have recent bloodwork, coarser than methylation, and you need the panel first.
- Questionnaire and wearable calculators. Free "how old are you really" quizzes and watch-based estimates score habits, not biology. Fine as a nudge, useless as a baseline to retest against.
Whichever route you take, the rule is the same: take a baseline, change one thing, retest with the same method.
Is there a biological age blood test?
Yes, and both methods on this page are blood tests, just not the kind with a needle in your arm. A finger-prick dried blood spot carries enough DNA for methylation analysis and enough IgG for glycan analysis, which is why the kits ship to your door instead of sending you to a lab. A venous draw adds nothing for these methods. The other blood route is the biomarker calculator above, which reads a routine panel, not DNA.
What can a biological age result tell you?
- A baseline. Where your biology sits today, against the population the test was trained on.
- A direction. Retested months later under similar conditions, the trend is the most trustworthy output these tests produce.
- Focus areas. Organ-system and biomarker breakdowns point at where the estimate is being dragged, which is a reasonable way to choose what to work on first.
What will a biological age test not tell you?
- It is not a diagnosis, and it does not screen for any disease. A good result is not a clean bill of health, and a bad one is not a verdict.
- It will not predict your lifespan. The estimates are population-trained statistics, not fortune telling.
- A single test carries noise. Hydration, illness, recent hard training, and lab variance all move the needle, which is why the trend beats the number.
- Results are not comparable across different companies or methods. A methylation age and a glycan age are different instruments reading different biology, and even two methylation tests from different labs are not interchangeable. Retest with the same test you started with.
Are biological age tests accurate?
Accuracy means two different things here, and it is worth separating them. The first is whether the estimate tracks real aging, and for the newer outcome-trained clocks and for glycan panels there is a credible research base behind that. The second is retest precision, whether the same sample gives the same answer twice, and this is where earlier clocks earned criticism. The newer generation of clocks was built specifically to improve that reliability, which is one reason test choice matters more than test count. Treat any single reading as an estimate with a margin around it, and put your trust in repeated measurements.
Epigenetic vs glycan testing at a glance
| Epigenetic (TruAge) | Glycan (GlycanAge) | |
|---|---|---|
| What it reads | DNA methylation patterns | Sugars on IgG antibodies |
| What it reflects | Age estimate, organ-system breakdown, pace of aging | Inflammatory side of biological aging |
| Sample | Finger-prick blood spot | Finger-prick blood spot |
| Responds to change | Months to years, pace markers sooner | Months |
| Typical retest | 6 to 12 months | 6 months |
The tests at Kove
Prices as of September 2026; the product page is the source of truth. Every kit is an at-home finger-prick collection with digital results, no fasting, adults 18 and over.
| Test | What you get | Turnaround | Price |
|---|---|---|---|
| GlycanAge Biological Age Test | Glycan-based biological age with lifestyle interpretation | A few weeks from sample received | $499 |
| TruAge Epigenetic Test | OMICmAge, SymphonyAge across 11 organ systems, DunedinPACE | 10 to 14 business days from sample received | $499 |
| TruHealth Biomarker Test | Epigenetic biomarker estimates across inflammation, immune, metabolic, nutrition, toxins, oxidative defense | 10 to 14 business days | $499 |
| TruAge + TruHealth combined | Both report sets from one collection | 10 to 14 business days | $850 |
How do people use biological age tests?
The pattern that makes sense is measure, change one thing, measure again. Take a baseline. Pick one intervention you will sustain, whether that is sleep, training, red light, heat, or cold. Hold it for six months, then retest with the same test, ideally at the same time of day, not during illness or right after a brutal training block. Changing five things at once feels productive but tells you nothing about what worked. The full retest protocol, including what to hold constant and how to tell a real change from noise, is in how people retest.
Can you pay with HSA or FSA?
Biological age testing is among the categories that commonly qualify with a Letter of Medical Necessity, decided per order by an independent licensed provider through Truemed at checkout. Details on the HSA and FSA page.
Frequently asked questions
How often should you take a biological age test?
Take a baseline, then retest at 6 to 12 months with the same biological age test. More frequent testing mostly measures noise, since the biology these tests read moves on a timescale of months.
Do I need to draw blood or fast?
No fasting, and no blood draw. Every kit we offer uses an at-home finger-prick blood spot that ships back to the lab in a prepaid mailer.
Which biological age test should I start with?
If you want the most detailed single report, the TruAge Epigenetic Test covers an outcome-trained age, 11 organ systems, and pace of aging. If the inflammatory picture interests you, or you want a test known to respond to lifestyle change within months, GlycanAge. If you cannot choose, one of each six months apart beats both at once.
Can you lower your biological age?
Possibly: studies have measured improvements in these markers following changes in sleep, training, body composition, and smoking status, and pace-of-aging markers respond fastest. Individual results vary, and no product on this site is sold as a way to guarantee it. The useful framing: the test tells you whether what you are doing is moving your markers.
Why did my result differ from another company's test?
Different tests read different biology with different training data. Results are not comparable across companies or methods, which is why the retest must use the same test as the baseline.
Is a biological age test a medical test?
No. The lab work runs in certified facilities, but the reports are wellness estimates, not diagnoses, and they do not replace bloodwork or checkups. Kove does not provide medical advice; see the medical disclaimer.
What does a biological age result look like?
An example: calendar age 42, epigenetic age 38.6, pace of aging 0.92. The markers read younger than the calendar and the estimated rate of aging is a little under one year per year. A glycan result reads the same way, a GlycanAge of 36 against 42 calendar years. The number to watch is the change at the retest, not the gap on day one.
Is a biological age test the same as a genetic test?
No. A genetic test reads the DNA sequence you were born with, which does not change. An epigenetic test reads the methylation tags sitting on top of that sequence, which shift with age and lifestyle. That is why the result can move between tests, and why an ancestry or genetic health-risk kit cannot report a biological age.
At what age is testing worth doing?
The kits are for adults 18 and over. Most buyers are 30 to 60, old enough for the markers to show real spread, young enough for the trend to be actionable for decades.
How long do results take?
TruDiagnostic kits report 10 to 14 business days after the lab receives your sample. GlycanAge typically takes a few weeks. Both deliver digitally.
Biological age testing in brief
Biological age tests are estimates, and used as estimates they are useful: a baseline, a direction, and a scoreboard for the one change you decided to make. Read a single number loosely, read a trend seriously, and always retest with the same test you started with.
Start with the TruAge Epigenetic Test or GlycanAge, both $499 with free US shipping, or see how testing fits a full routine in building your first stack.
