Are commercial biological age tests based on DNA methylation worth the money?

Commercial biological age tests based on DNA methylation measure something real, but what exactly they measure varies considerably from clock to clock, and the translation into personal action is more limited than the marketing suggests. The CALERIE study illustrates this well: two years of eating 25% less slowed the rate of ageing in 220 adults, but only as measured by the DunedinPACE clock. The well-known clocks PhenoAge and GrimAge showed no significant change in that same study¹. In other words: if you measure the same intervention with three different tests, you get three different answers. That is a fundamental problem for anyone buying a commercial test to find out their 'biological age'.

Yet the clocks are not worthless. In a retrospective study of 200 glaucoma patients, greater epigenetic age acceleration, measured with the Horvath, Hannum, and GrimAge clocks, was associated with faster deterioration of the visual field and the retinal nerve fibre layer. Each additional year of Horvath age acceleration was associated with a 15% higher likelihood of rapid glaucoma progression². This is an association in a specific patient group, not evidence that the test works as a screening tool for the general population.

DNA methylation tests are also being developed for early cancer detection, and that is where more concrete clinical applications lie. The THUNDER study validated a blood test capable of detecting six types of cancer simultaneously: in an independent validation set of over 1,000 people, the test achieved a specificity of approximately 99% (few false positives) but a sensitivity of approximately 69%, and for early-stage cancer that fell to approximately 60%³. One of the developers, Burning Rock Biotech, has commercial interests, which places the results in a different light. For women, the WID-qEC test via a cervico-vaginal swab also provides a signal for ovarian cancer (adjusted odds nearly three times as high with a positive test), but the probability that a positive result actually indicates ovarian cancer remains low in the general population, and the combination strategy that could improve precision has so far only been modelled on paper⁴. Several authors of that study have commercial interests through Sola Diagnostics.

A separate caveat applies to DNA methylation-based telomere length estimation (DNAmTL), which some providers include as part of their panel. Research shows a certain correlation with direct measurement methods such as flow FISH and qPCR, but the methods are not fully interchangeable⁵. The evidence base for this estimate is limited.

What does this mean in practice? The best-supported application of DNA methylation clock measurement is currently DunedinPACE as an outcome measure in scientific intervention research, not as a personal consumer measurement. For cancer detection, the tests have not yet been approved as standard screening tests and have limitations in early-stage sensitivity. Anyone considering a commercial biological age test should understand that the different clocks contradict one another, that a single measurement provides no solid basis for lifestyle choices, and that the only proven way to favourably influence the DunedinPACE clock in a controlled study was caloric restriction, with a small effect.