Your birthday counts years. Biological age tries to estimate how your body is aging at a cellular level — often using patterns in DNA methylation or other molecular signals. It’s a research idea that’s moved into consumer reports, not a second passport number.
The simple version
- Chronological age = time since birth.
- Biological age = an estimate from biomarkers (commonly epigenetic “clocks”) that correlate with aging and health outcomes in studies1,2,3,4.
- A report might say your biological age is higher or lower than your years. That gap is a signal for learning, not a diagnosis.
Different clocks and labs use different tissues, algorithms, and reference groups. Two reports can disagree and still both be “valid” in their own framing. Treat the number as a starting point for understanding, not a verdict.
What it’s useful for
- Giving language to “how am I aging?” beyond the calendar
- Tracking change over time with the same method
- Opening a conversation about sleep, metabolic health, inflammation, and other levers people already care about
Our job at cells.com is to help you interpret a result you already have — or point you to reputable third-party tests if you’re starting from zero — then turn that into a clear educational action plan. We don’t run the test or act as your clinician.
What this is not. Education only. Biological age estimates are not medical diagnoses. They do not replace care from a qualified clinician. cells.com does not diagnose, treat, prescribe, run laboratory tests, or ship kits. Nothing here is medical advice.
How this shows up on cells.com
If you already have a TruAge, Elysium, GlycanAge, or similar result, you’ll be able to bring it to cells.com for plain-language interpretation. If you don’t, we’ll help you understand what a first test is — without pretending we’re the lab.
References
- Horvath S. DNA methylation age of human tissues and cell types. Genome Biology. 2013;14(10):R115. doi:10.1186/gb-2013-14-10-r115
- Hannum G, Guinney J, Zhao L, et al. Genome-wide methylation profiles reveal quantitative views of human aging rates. Molecular Cell. 2013;49(2):359–367. doi:10.1016/j.molcel.2012.10.016
- Lu AT, Quach A, Wilson JG, et al. DNA methylation GrimAge strongly predicts lifespan and healthspan. Aging (Albany NY). 2019;11(2):303–327. doi:10.18632/aging.101684
- Belsky DW, Caspi A, Corcoran DL, et al. DunedinPACE, a DNA methylation biomarker of the pace of aging. eLife. 2022;11:e73420. doi:10.7554/eLife.73420
Simon Ng is the founder of cells.com. He has spent more than a decade on biotech finance executive teams, including at Quark Pharmaceuticals and Adverum Biosciences, and holds an MBA.