Biological age tests: useful health signal or expensive number?

What is a biological age test trying to measure?

People of the same chronological age can differ greatly in health and physical capability. Biological-age research tries to capture some of that variation using measurable features of the body.

The result comes from a model. Researchers select measurements and develop a way to combine them into an estimate or score. Some models aim to resemble chronological age; others are designed around health outcomes or the pace of biological change.

The Biomarkers of Aging Consortium describes this variety and the different questions ageing biomarkers may address.¹

That helps explain an important point: “biological age” is not one universally defined measurement. Before interpreting a result, it helps to know which model produced it and what that model was designed to represent.

Why can two tests give different ages?

They may be looking at different things. A model based on routine blood measurements is not the same as a model based on DNA methylation, a pattern of chemical marks associated with DNA regulation.

Even tests within the same broad category can be trained differently. One may be better at estimating calendar age, while another is intended to reflect patterns related to health risk.

The consortium's work highlights the need for validation, comparability and confidence that a test performs appropriately across different populations.²

Two different numbers therefore do not necessarily mean one laboratory made a mistake. They may reflect different models answering different questions. Comparing them as if they were readings from the same thermometer can be misleading.

Is an older biological age a reason to worry?

It is a reason to ask what the result means, rather than assume that your body is literally older than you are.

If the model uses conventional measurements, some of the underlying findings may deserve attention in their own right. The useful discussion is then about those findings, your medical history and appropriate next steps.

A score should also be interpreted with an understanding of the model's uncertainty. It cannot establish your future health or tell you what you will be able to do at a particular age.

You do not need to ignore the result, but you can keep it in perspective. Ask what is clinically useful within it and whether it adds anything to information already available.

Does a younger score prove that you are healthier?

Not on its own. A model can summarise selected patterns while missing other important aspects of health.

For example, a number does not tell you how comfortably you climb stairs, whether pain is restricting you or whether a symptom needs investigation. Those questions deserve attention regardless of the score.

This is the difference between a research marker and a complete assessment of a person. The consortium distinguishes predicting outcomes from establishing that a biomarker can reliably stand in for the effects of an intervention.¹

For you, the practical meaning is simple: a favourable score can be interesting, but it should sit alongside the things we can assess and act on more directly.

What does research on changing biological age actually show?

One much-discussed study analysed DNA methylation measures in the CALERIE trial, a two-year randomised trial of calorie restriction in healthy adults.

The analysis found a small change in one measure, DunedinPACE, but no significant change in PhenoAge or GrimAge. It did not establish that participants lived longer or avoided disease because the measure changed.³

This is useful research because it explores whether certain biomarkers respond to an intervention. It also shows why the wording matters: a change in one model is not the same as proving that a person's whole body has become younger.

The study is not a reason to adopt calorie restriction on your own. Decisions about nutrition need to fit your health and nutritional needs, rather than a desire to reproduce a research score.

Can biological-age tests help you track progress?

They may contribute to a discussion, particularly if the same method is used and the result has a clear purpose. But a changed score needs careful interpretation.

Ask whether the difference is likely to reflect a meaningful change or could be influenced by measurement variation. Also ask whether the test has been validated for the way it is being used.

The 2024 validation paper identifies important barriers in translating ageing biomarkers into dependable clinical use.² Repeating a measurement does not, by itself, solve those problems.

For a practical plan, it helps to agree in advance what you would do differently with the result. If the next step would be the same whatever the number, another measure may be more useful for reviewing your progress.

What can you track that is easier to interpret?

Begin with the reason you wanted the test. Are you hoping to stay stronger, feel more comfortable during activity or understand a medical risk?

Relevant medical measurements can help review a condition or treatment plan. Repeatable physical tasks can show changes in performance. Everyday observations can tell you whether a walk, lifting task or valued activity feels more manageable.

These measures are not perfect either, but their relationship to your goals is often clearer. You can discuss what changed and whether the plan needs adjusting.

For example, being able to enjoy a longer walk with your partner is a meaningful outcome in its own right. It does not need to be translated into an age reduction to count as progress.

How should you decide whether a test is worth paying for?

Consider what you want from it. Curiosity is understandable, but it is different from needing information that will change medical care.

Ask which model is used, what evidence supports its interpretation and how the result will be explained. If a service claims that a lower score proves an intervention works, ask whether meaningful health outcomes have also been demonstrated.

It may help to compare that purchase with other ways of supporting your goals, such as an appropriate assessment, advice about a symptom or help establishing an activity routine.

There is no need to dismiss every developing technology. A thoughtful approach can recognise scientific promise while making sure your time and money support something useful to you now.

How does biological age fit within HealthSpan in Milton Keynes?

Hanbury's published HealthSpan packages include a biological-age output. It belongs within the wider assessment, alongside blood biomarkers, body composition, physical function and cognition.

The central conversation remains about your health, your capabilities and the changes that may help you. The age estimate should not override a clinically important finding or become the sole measure of success.

You can use Contact us to ask how the result is calculated and explained, and to discuss the assessment packages and prices before booking.

Related reading: Can you measure cognitive health before you notice a problem?

Why Hanbury Health is different

HealthSpan gives you the opportunity to discuss an appealing headline number within a fuller medical and functional picture. The consultant can explain which underlying findings deserve attention and which conclusions the model cannot support.

The practical emphasis is on helping you act on useful information. That may mean addressing a health risk, working on strength or building fitness for activities you want to keep enjoying. Those goals remain worthwhile whatever an age model reports.