Buyer's guide
How to choose a biological age test
Your biological age is an estimate of how old your body works, not how many birthdays you have had. Several methods claim to measure it, and they are not equal. What matters is not the brand on the box, it is the method underneath and whether it hands you a number you can change.
This guide walks through the main approaches, what each one is good and bad at, and how to choose based on accuracy, cost, and whether it tells you what to do next.
How to choose
- What it measures. Cellular aging, organ function, or overall fitness are very different signals.
- The evidence behind the method. Is the approach validated in real studies, or is it a proprietary black box?
- Can you act on it. A number you cannot move is trivia. Markers you can change are a plan.
- Cost and access. A lab-only test you take once a year is different from something you can track continuously.
The options, honestly
Epigenetic clocks (DNA methylation)
These read chemical marks on your DNA and are the most studied way to estimate cellular aging. They are powerful for research. The catch for everyday use is that they need a lab sample, cost more, and usually give you a single number without telling you which levers to pull.
Biomarker and fitness based estimates
These combine blood markers you can move, such as ApoB, HbA1c and inflammation, with function like VO2 max and grip strength. They are practical, repeatable, and every input is something you can improve. This is the approach behind Jevity's free assessment and the living Digital Twin.
Wearable derived estimates
Rings and watches infer aging from resting heart rate, heart rate variability and sleep. They are great for spotting trends day to day, but less precise as a standalone number, and best used alongside bloodwork rather than instead of it.
The bottom line
For most people, an estimate built from markers you can change beats a precise number you cannot. Start with a biomarker and lifestyle based read, act on the one or two biggest levers, then re-test. If you want the research-grade cellular number as well, add an epigenetic test once a year on top.
Frequently asked
How accurate are biological age tests?
Accuracy depends entirely on the method. Epigenetic clocks are the most validated for cellular aging, while biomarker and wearable estimates are strong for tracking change over time. No test is a diagnosis. The most useful way to read any of them is as a trend you move in the right direction, not a single verdict.
Epigenetic versus blood-based, which is better?
They answer different questions. Epigenetic clocks estimate cellular aging and are excellent for research. Blood and fitness based estimates use markers you can actually change, so they are better for building and tracking a plan. Many people use a blood based read often and an epigenetic test occasionally.
Can I actually lower my biological age?
You can move the inputs. Sleep, resistance training, protein adequate nutrition, stable glucose and lower inflammation are the strongest levers, and improving them improves the markers most tests are built on. Jevity turns those levers into a plan and tracks the change.
Is a free biological age test worth it?
A free estimate that uses real inputs and shows you what to do is a genuinely useful starting point. It will not replace lab work, but it orients you fast and costs nothing. Jevity's assessment takes about two minutes.
How often should I test?
For biomarker and wearable based tracking, every few months is plenty to see change. For epigenetic clocks, once a year is typical, since cellular aging moves slowly.
See your biological age in two minutes
Free, no card, and it shows you the biggest levers to lower it.
Get my biological ageKeep reading: What is biological age? · The biomarkers behind it · Track it with your Digital Twin
Educational only, not medical advice. Methodology at editorial standards. Jevity is operated by Upcapital Global FZCO, Dubai Silicon Oasis, UAE.