Missed “short & sweet” instalment no. 7 on “biological age”? Catch up here!
Do you remember the iconic “Jellyfish” Swatch of the 1980s? Thanks to its transparent plastic casing, you could directly observe the workings of its inner movement with its colourful hands, cogwheels and battery.
Wouldn’t it be nice (well at least sometimes…) if our bodies were jellyfish-like? That would make biological age determination so much easier, wouldn’t it?
Unfortunately, as we already found out in our previous “short & sweet” instalment, even a quasi-radiological gaze (or that of an MRI/CT scan, for that matter) is not sufficient to capture all the subtle signs of ageing as they unfold in and over the body.
Indeed, the task of determining biological age is particularly challenging because each manifestation of ageing can be measured using different physiological, biochemical and even cognitive markers.
More concretely: your next health check-up may involve blood and/or urine tests, based on various markers that reference deficiencies, disease and ageing. In parallel, your GP might assess the state of your lungs, measure your blood pressure, test your flexibility, check your skin, eyesight and hearing, and maybe weigh you. S/he may question you about your family or social entourage, your lifestyle, your hobbies and your moods. And if anything strikes the doctor as amiss, you may be sent to a specialist for more precise or comprehensive testing of one or more bodily systems. Last but not least, if you complain about forgetfulness, s/he may even recommend cognitive testing…
This will provide your physician with a multi-faceted picture of your overall health and biological ageing, as s/he compares your data with reference data from your contemporaries. But even for a physician, it will probably remain a complex if not confusing tableau.
This is because the body is so much more than just the sum of its parts.
Indeed, you cannot infer the overall health of your body by just adding up the health status of your different organs and tissues.This is because they are embedded in various complex systems that communicate in different ways, using specific pathways and signals, while co-regulating each other in the process.
In recent years, a number of modalities have arisen for individuals who wish to obtain more comprehensive insights on their health and ageing.
Beyond the ones we already mentioned, the Max-Planck Institute for Biology of Aging quotes advanced metabolomic tests, proteomic aging clocks as well as telomere and epigenetic testing. While these novel approaches already show significant promise for a more streamlined approach to biological age determination, they still require further validation and systematic comparison (Zurbuchen, 2025).
So, almost four decades after the term “biological age” was first coined (Baker 1988), there is still no gold standard to calculate biological age (Mathur 2024; Zurbuchen, 2025).
This is due to a number of factors. Most prominently (and soberingly!), ageing researchers do not even agree on the foundational principles of biological aging (Gladyshev, 2024). Then, there is the wide variety of biological ageing scores (KDM, PCA, MLR, HD…) undergirded by different sets of biomarkers of ageing (e.g. systolic blood pressure, waist circumference, glucose, memory, etc.), depending on the specific objective underlying the determination of biological age (Zurbuchen, 2025). To make things even more challenging, biomarkers, to acquire true legitimacy, should undergo biological, cross-species, predictive, analytical and clinical validation (Moqri, 2024).
So, if you didn’t have a headache before starting the article, you may be feeling the first pang…
But despair not: even though a broad consensus is not yet on the horizon, the newer "-omics" methods, such as proteomics, metabolomics, microbiomics or epigenomics, offer the perspective of a more comprehensive and in-depth panorama of biological ageing – especially if they are combined.
To date, however, epigenomics boasts the longest expertise in the field of biological age determination and newer epigenetic clocks still offer the most convincing biological age estimates.
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Sources & further reading
“How can you measure biological age?”. Max-Planck-Institute for Biology of Ageing. Online: https://www.age.mpg.de/211116/how-can-you-measure-biological-age
George T. Baker, Richard L. Sprott. “Biomarkers of aging”. Experimental Gerontology, Volume23, Issues 4–5, 1988, 223-239. doi: 10.1016/0531-5565(88)90025-3. Online: https://www.sciencedirect.com/science/article/abs/pii/0531556588900253?via%3Dihub
Zurbuchen, Rebecca, von Däniken, Anna, Janka, Heidrun, von Wolff, Michael, Stute Petra. „Methods for the assessment of biological age – A systematic review”. Maturitas. 2025 Feb 7:195:108215. doi: 10.1016/j.maturitas.2025.10821. Online : https://www.maturitas.org/article/S0378-5122(25)00023-4/abstract
Mathur A, Taurin S, Alshammary S. “New insights into methods to measure biological age: a literature review.” Frontiers in Aging. 2024 Dec 16;5:1395649. doi:10.3389/fragi.2024.1395649. Online: https://www.frontiersin.org/journals/aging/articles/10.3389/fragi.2024.1395649/full
Vadim N. Gladyshev, Benjamin Anderson, Hanna Barlit, Benjamin Barré et al, “Disagreement on foundational principles of biological aging”.. PNAS Nexus, Volume 3, Issue 12, December 2024, pgae499, doi:10.1093/pnasnexus/pgae499. Online: https://academic.oup.com/pnasnexus/article/3/12/pgae499/7913315
Moqri, M., Herzog, C., Poganik, J.R. et al. “Validation of biomarkers of aging”. NatMed 30, 360–372 (2024). doi: 10.1038/s41591-023-02784-9. Online: https://pmc.ncbi.nlm.nih.gov/articles/PMC11090477/
Rutledge J, Oh H, Wyss-Coray T. “Measuring biological age using omics data". Nat Rev Genet. 2022 Dec;23(12):715-727. doi: 10.1038/s41576-022-00511-7. Online: https://www.nature.com/articles/s41576-022-00511-7
Leitner, Brooks. “Biological Age: The Science and History Behind the Biomarker of Health”. Where Theory Meets Practice. Feb. 15, 2025. Online: https://brooksleitner.substack.com/p/biological-age-the-science-and-history
Illustration
pixabay & epiAge
FotisMichalainas / pexels
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