How to Measure Your Biological Age: Tests Compared

What is biological age?

Biological age is an estimate of how old your body seems at the cellular level, as opposed to your chronological age, the number of birthdays you have had. Two people born in the same year can age at very different rates, depending on genetics, lifestyle, and environment. Biological age tests try to measure that difference.

Scientists estimate biological age by looking at markers that change predictably over time, such as chemical tags on your DNA, the sugar structures on your antibodies, or routine blood results. Each test measures something slightly different, so results from one test cannot be compared directly with another.

The appeal is simple: biological age gives you a way to see something that is otherwise invisible, and to track whether your habits are moving it in the right direction.

Biological age tests compared

The main types of biological age test are epigenetic clocks, glycan age tests, blood biomarker calculators, telomere tests, and functional fitness tests. Epigenetic clocks have the deepest research base. Blood biomarker calculators are the most affordable. Functional tests such as grip strength are free and closely linked to healthy aging.

To understand the biology behind these markers, see our posts on epigenetic alterations and telomere attrition, two of the hallmarks of aging.

How to choose a test and get useful results

The best biological age test is the one you will repeat in the same way over time. A single result is a snapshot; the trend between tests is what tells you something. Choose one test type, use the same provider each time, and retest every six to twelve months.

• Decide what you want to know. For a broad, research-backed picture, an epigenetic clock is the usual choice. For an inflammation-focused view, consider glycan age. On a budget, a biomarker calculator using routine blood work is a good start.
• Stick with one provider. Different labs and clocks give different numbers, so switching makes your results hard to compare.
• Test under similar conditions. Avoid testing during an illness or right after an unusually stressful period, which can affect some markers.
• Retest at sensible intervals. Six to twelve months gives lifestyle changes time to show.
• Look at the whole picture. Pair your test with functional measures such as grip strength and how you feel day to day.
• Discuss results with a professional. A clinician can help you interpret results alongside your wider health.

Habits that support healthy biological aging

The habits most consistently linked with healthy aging are regular exercise, quality sleep, a whole-food diet, stress management, and avoiding smoking. Supporting your cells' natural renewal processes, including autophagy, is another area of growing interest in longevity research.

• Move every day. Combine aerobic activity with strength training to keep muscle and fitness as you age.
• Prioritize sleep. Much of your body's repair work happens overnight. See the power of sleep for longevity.
• Eat for longevity. Focus on whole foods, including foods high in spermidine. 
• Give your body breaks from eating. Time-restricted eating supports autophagy, your cells' recycling system.
• Manage stress. Chronic stress affects many of the markers these tests measure. Simple practices such as time in nature can help.
• Support cellular renewal. Spermidine is a natural polyamine that induces autophagy. Learn more in the benefits of spermidine.

Frequently asked questions

What is the most accurate biological age test?

Epigenetic clocks based on DNA methylation have the strongest research base. Newer versions, such as GrimAge and DunedinPACE, were designed to better reflect health and pace of aging. No test is perfect, and results can vary between labs.

Can you lower your biological age?

Research suggests biological age markers can shift in response to lifestyle changes such as diet, exercise, sleep, and stress management. Results vary between people and between tests, so track trends over time rather than relying on a single number.

How often should I test my biological age?

Every six to twelve months is a sensible interval for most people. Testing more often rarely adds useful information, because meaningful change takes time.

Can I measure biological age at home?

Yes. Many epigenetic and glycan tests use a saliva sample or finger-prick blood kit that you post back to the lab. Grip strength and walking speed can also be tracked at home.

What is the difference between biological age and chronological age?

Chronological age is how long you have been alive. Biological age is an estimate of how your body is aging at the cellular level, which may be higher or lower than your chronological age.

Support cellular renewal with Primeadine

Tracking your biological age is a great way to stay motivated, and supporting your cells every day is how you put that motivation into practice. Primeadine Original delivers food-derived spermidine from defatted Japanese wheat germ, and Primeadine GF is the gluten-free version, made from Okinawan chlorella. Both are third-party tested and developed with scientific advisors from the University of Oxford to support healthy aging and cellular renewal.

This article is for informational purposes only and is not intended as medical advice. Please speak with your healthcare provider before starting any new supplement, especially if you are pregnant, breastfeeding, taking medication, or managing a health condition.

References

1. Horvath S. DNA methylation age of human tissues and cell types. Genome Biology. 2013;14(10):R115. https://doi.org/10.1186/gb-2013-14-10-r115
2. Levine ME, et al. An epigenetic biomarker of aging for lifespan and healthspan. Aging. 2018;10(4):573–591. https://doi.org/10.18632/aging.101414
3. Lu AT, et al. DNA methylation GrimAge strongly predicts lifespan and healthspan. Aging. 2019;11(2):303–327. https://doi.org/10.18632/aging.101684
4. Belsky DW, et al. DunedinPACE, a DNA methylation biomarker of the pace of aging. eLife. 2022;11:e73420. https://doi.org/10.7554/eLife.73420
5. Krštić J, et al. Glycans are a novel biomarker of chronological and biological ages. Journals of Gerontology: Series A. 2014;69(7):779–789. https://doi.org/10.1093/gerona/glt190
6. López-Otín C, et al. Hallmarks of aging: an expanding universe. Cell. 2023;186(2):243–278. https://doi.org/10.1016/j.cell.2022.11.001