How can I measure my biological age?
Epigenetic clocks, particularly GrimAge and PhenoAge, currently offer the best estimate of your biological age, but they are not yet ready for straightforward home use and require expert interpretation.
DNA methylation is currently the best-supported method for estimating biological age. Specialised measurement tools called epigenetic clocks read patterns in the way your DNA is 'tagged', without the genetic code itself changing. Those patterns shift with age in a predictable way, which makes it possible to get an estimate of how old your body looks biologically.
Two clocks stand out for their predictive power. GrimAge, which takes into account smoking history and the levels of certain proteins in the blood, strongly predicted in studies with thousands of participants who died earlier, developed a cardiovascular disease, or was diagnosed with cancer. A second clock, PhenoAge, is based on clinical measurements and outperforms older clocks when it comes to predicting death, physical functioning, and diseases such as Alzheimer's. People who are epigenetically 'older' than their calendar age also tend to have more chronic inflammation and less well-functioning energy-producing structures in their cells.
Alongside DNA methylation, there are methods that look at gene activity, protein profiles, or the products of metabolism. Using machine learning, these are combined into new types of 'clocks'. Which combination works best is still very much an active area of research.
Telomere length, the protective caps at the ends of chromosomes, is sometimes mentioned as a measure of biological age. Current reviews, however, clearly rank it below epigenetic methods, with more limited predictive value.
There are still real limitations. Epigenetic clocks are sensitive to the types of cells present in a blood sample, which can influence the result. Exactly how to interpret the outcomes has not yet been fully resolved. And the fact that a higher biological age is linked to worse health outcomes does not yet mean that the clock can show whether a treatment has genuinely changed anything. Long-term follow-up studies are needed for that.
All claims are based on reviews. GrimAge has been validated in large studies (thousands of people). Long-term data from intervention studies are lacking. All associations measure correlation only; cause and effect have not been established.
How often does it make sense to remeasure your biological age?
Clocks change slowly: two years is a realistic minimum to see the effect of a lifestyle change, but whether a lower score truly means you will live longer has not been proven. Track your daily weight, activity and blood pressure more frequently, and treat a remeasurement as a two-year check-in, not a weekly dashboard.
Can you see your biological age in your blood pressure?
A rising systolic blood pressure and a widening gap between the upper and lower numbers are recognisable signs of vascular ageing, but a truly reliable picture of your biological vascular age requires additional measurements that a general practitioner does not routinely perform.
What do biological ageing clocks actually measure?
Biological ageing clocks measure methylation patterns on your DNA and show that loss of cell identity resets the counter to zero, while ageing drives it upward. That makes them valuable measuring instruments, although a lower clock score does not automatically translate to better functioning.
How reliable is a protein test for measuring your biological age?
A protein test is a promising and now reasonably well-supported way to measure biological ageing, particularly as a predictor of disease and death, but its translation into personal use is still very much in development.
Can you really lower your biological age, and does research support this?
There are promising hints that biological age is measurable and perhaps steerable, but this has not been proven. Wait for larger studies in people before basing major decisions on this.
How quickly can you change your biological age with exercise?
Regular moderate to vigorous exercise is associated with a biological age that comes out 1 to 3 years lower, and molecular changes in muscles are measurable after just a few weeks. Whether a lower score on an epigenetic clock truly means living healthier or longer has not yet been proven: treat it as an encouraging signal, not a guarantee.