Last updated 24 October 2026
You've probably heard someone say they feel younger than their age. As it turns out, that's not just a feeling, it's measurable biology.
There's a growing distinction in longevity science between two very different numbers, the age on your birth certificate, and the age your body is actually operating at. One you can't change. The other, increasingly, you can.
Chronological age is simply how long you've been alive. Biological age, sometimes called physiological age, is a measure of how well your body's cells, tissues, and systems are actually functioning relative to what's typical for your years.
Two people who are both 45 can have biological ages that differ by a decade or more. One might have the cellular profile of a 38-year-old. The other might already be showing the cellular hallmarks of someone in their mid-50s.
This matters because biological age is a better predictor of health outcomes than chronological age. It's more closely linked to risk of chronic disease, cognitive decline, and how long you're likely to live in good health, what researchers call healthspan.
The most established method uses something called an epigenetic clock. Your DNA doesn't just carry your genetic code, it also carries chemical tags called methylation marks that change in predictable patterns as you age. Scientists can analyse these patterns to estimate how old your cells are behaving.
The most widely cited of these is the Horvath Clock, developed by UCLA professor Steve Horvath, which examines methylation patterns across hundreds of sites in the genome (Horvath, 2013). More recent versions, including the GrimAge and DunedinPACE clocks, have become even better at predicting mortality and the rate at which someone is ageing.
Other markers researchers use to estimate biological age include
Consumer tests using saliva or blood samples now allow individuals to get a rough biological age estimate, though the science is still maturing, and results should be read as indicators rather than definitive verdicts.
Biological age isn't fixed. Certain factors accelerate it, pushing your cellular age ahead of your years (López-Otín et al., 2013). Some of these follow a different timeline in men, as we explain in how men age.
This is where the research gets interesting.
A small 2019 study published in Aging Cell, the TRIIM trial, found that a combination of growth hormone, DHEA and metformin reversed epigenetic age by an average of around 2.5 years over 12 months in nine men (Fahy et al., 2019). These were prescription treatments under medical supervision, but the result showed that epigenetic age can move.
More accessibly, a 2021 pilot study in the journal Aging found that an 8-week programme of diet, sleep, exercise and relaxation guidance, with probiotic and plant-nutrient supplements, was linked to epigenetic age 3.23 years lower than a control group, in 43 men (Fitzgerald et al., 2021).
The specific interventions with the strongest evidence for slowing or partially reversing biological ageing include
The honest answer. Full reversal is not yet achievable through lifestyle alone. But meaningful slowing, and in some cases partial reversal, increasingly appears to be within reach, particularly when interventions address the upstream biological drivers rather than individual symptoms.
You may also have seen a "metabolic age" figure on a smart scale or gym report. The two are often confused, but they measure different things.
Metabolic age compares your basal metabolic rate, the energy your body uses at rest, with the average for people of different ages. It is usually estimated from weight, height and body composition, so it mostly reflects muscle mass and body fat.
Biological age goes deeper. It looks at how your cells and tissues are ageing, using markers like DNA methylation, inflammation and metabolic health. A good metabolic age is a useful sign, but it is a snapshot of body composition rather than a measure of cellular ageing.
The habits that improve one tend to improve the other. Building and keeping muscle, sleeping well and keeping blood sugar steady all show up in both numbers.
The shift from thinking about age as a fixed number to a malleable biological state is one of the most important reframings in modern health. It moves the conversation from inevitable decline to active management.
You can't control when you were born. But the research increasingly suggests you have more influence over your biological age, and therefore your long-term health, than most people realise.
That influence starts at the cellular level, with inflammation, oxidative stress, mitochondrial function, and metabolic health. Address those systems consistently, and the biology tends to follow.
No supplement can promise to lower your biological age. But several of the drivers above respond to the right nutrients at the right doses. Daily Vitals brings together ten actives, including patented Levagen®+ and HydroCurc®, dose-matched to 22 clinical trials.
It isn't a shortcut, and it doesn't replace sleep, movement or good food. It's a simple daily ritual that supports the same upstream systems the research points to. Feel better now. Age better later.
Biological age tests and supplements are tools for understanding and supporting your health, not a diagnosis. If a test result worries you, or you have new or worsening symptoms, speak to your GP.
Speak to your GP or pharmacist before starting any new supplement if you take prescription medicines, are pregnant, trying to conceive or breastfeeding, are due to have surgery, or have a medical condition. Some ingredients can interact with certain medicines, including blood thinners and blood pressure tablets. Always follow the dose on the label, and remember that a food supplement should not replace a varied diet.
Biological age is a measure of how well your body's cells, tissues and systems are functioning compared with what is typical for your years. Chronological age is simply how long you have been alive.
The most established method uses epigenetic clocks, which read DNA methylation patterns (Horvath, 2013). Other markers include telomere length, inflammatory markers such as CRP, metabolic markers and physical performance such as grip strength and VO2 max.
No. Metabolic age compares your resting energy use with the average for different ages and mostly reflects muscle mass and body fat. Biological age looks at how your cells and tissues are ageing.
Small studies suggest epigenetic age can move. A 2021 pilot study linked an 8-week programme of diet, sleep, exercise and relaxation guidance to epigenetic age 3.23 years lower than a control group in 43 men (Fitzgerald et al., 2021). Full reversal through lifestyle alone has not been shown, but meaningful slowing looks achievable.
They can give a rough estimate, but the science is still maturing. Read results as indicators rather than a definitive verdict, and speak to your GP about any health concerns.
Keep reading
What is longevity and why does inflammation matter?
Longevity, healthspan and the inflammation epidemic
AEVUM's five longevity systems
References
Blackburn, E.H. and Epel, E.S. (2017). The Telomere Effect. Grand Central Publishing.
Briskey, D., Roche, G. and Rao, A. (2022). The effect of a dispersible curcumin (HydroCurc®) compared to a placebo for reducing joint pain in an adult population, a randomised, double-blind study. Complementary Medicine Research, 29(6), 429–436. doi.org
Fahy, G.M. et al. (2019). Reversal of epigenetic aging and immunosenescent trends in humans. Aging Cell, 18(6), e13028. doi.org
Fitzgerald, K.N. et al. (2021). Potential reversal of epigenetic age using a diet and lifestyle intervention, a pilot randomized clinical trial. Aging, 13(7), 9419–9432. doi.org
Horvath, S. (2013). DNA methylation age of human tissues and cell types. Genome Biology, 14(10), R115. doi.org
Hou, S. et al. (2023). Efficacy and optimal dose of coenzyme Q10 supplementation on inflammation-related biomarkers, a GRADE-assessed systematic review and updated meta-analysis of randomized controlled trials. Molecular Nutrition & Food Research, 67(13), e2200800. doi.org
López-Otín, C. et al. (2013). The hallmarks of aging. Cell, 153(6), 1194–1217. doi.org
Rao, A., Ebelt, P., Mallard, A. and Briskey, D. (2021). Palmitoylethanolamide for sleep disturbance, a double-blind, randomised, placebo-controlled interventional study. Sleep Science and Practice, 5(1). doi.org
Steels, E. et al. (2019). A double-blind randomized placebo controlled study assessing safety, tolerability and efficacy of palmitoylethanolamide for symptoms of knee osteoarthritis. Inflammopharmacology, 27(3), 475–485. doi.org
Tiekou Lorinczova, H. et al. (2022). Co-administration of iron and bioavailable curcumin reduces levels of systemic markers of inflammation and oxidative stress in a placebo-controlled randomised study. Nutrients, 14(3), 712. doi.org
Balance inflammation, support cellular resilience and build long-lasting vitality.
Welcome Gift
