What biological age tests can and can’t do
Key Takeaways
The latest tests predict biological age using epigenetic clocks based on DNA methylation, which increases with age.
Some doctors incorporate biological age tests into their clinical practice, noting they can be part of preventive health by measuring the effects of certain lifestyle habits and potential interventions.
Even so, clinical applications of biological age tests require further research. That’s why interpreting results alongside clinical biomarkers and medical assessments can lead to better outcomes.
Biological age tests have recently gained widespread attention on social media, where influencers and celebrities with large followings share their experiences of discovering how their “chronological age” compares with their “biological age.”
Why? Because they believe biological age tests can help demystify how well they are aging, and if there are certain lifestyle changes they can implement to help slow the aging process. MDLinx spoke with the experts to investigate these claims, and researched patient forums to get a better idea of how these tests are being used among your patients.
What’s the point?
Opinions remain divided about how useful biological age tests can be. Some consumers are skeptical, questioning the value of spending hundreds of dollars on a test that may not provide an accurate or actionable result.[][] Others report troubling outcomes, such as being told they are decades older than their chronological age, without receiving any meaningful guidance to address the discrepancy.[]
@pagesix Kim Kardashian is "livid" at Khloé Kardashian when she finds out Khloe ages 28% slower than the average person.
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Meanwhile, there is a growing group of enthusiasts who embrace biological age testing as part of a broader "biohacking" trend.[] These individuals often view the test as a motivational tool to promote healthier behaviors and enhance longevity.
What the science says
Research is ongoing to find the most accurate method to detect biological age. Current methods include mathematical modeling of certain blood biomarkers, molecular and genetic markers, and epigenetic clocks.[] The tests based on epigenetic clocks are the newest and most popular ones available to consumers, and many companies sell these tests online. Typically, they require a blood sample that is sent to a lab for analysis.
Steve Horvath, PhD, first proposed the epigenetic clock.[] Since then, more advanced clocks have been developed, with all based on DNA methylation, which increases with age. However, these estimators take different biomarkers or lifestyle factors, such as smoking, into account.
Francois-Xavier Pellay, PhD, longevity scientist and entrepreneur, CEO of Bimini Biotech in Croatia, tells MDLinx, ‘‘The DNA methylation test is for now considered the ‘gold standard’ in calculating biological age, but there are many different providers with very different quality of tests.’’
What they can (and can't) do
Manuj Agarwal, MD, radiation oncologist and integrative longevity medicine physician, explains, ‘‘Epigenetic changes reflect systemic aging and cellular health, offering a predictive value for lifespan and aging-related diseases. If an individual finds out that their biological age is younger than their chronological age, it’s a positive indicator that their current lifestyle and health habits are working in their favor.’’
Research also supports the potential benefits of biological aging clocks in healthcare. In a 2023 review published in Cell, researchers evaluated studies involving different epigenetic clocks, and found that some were able to detect the effects of interventions such as diet, exercise, and dietary supplements on biological age.[]
When it comes to the clinic, some doctors believe these tests can help determine the optimal time for disease screenings, reduce healthcare costs, and guide treatment decisions.
Dr. Pellay gives an example: ‘‘A 45-year-old patient with a biological age of 55 should definitely consider getting tested for the risk of prostate or breast cancer, for example.”
"[These tests] can increase awareness and prevention, including drastic lifestyle changes, which would lead to decreased healthcare costs."
— Francois-Xavier Pellay, PhD
However, Dr. Pellay adds, ‘‘Biological age tests don’t precisely predict when specific diseases will appear or offer universal insights across all individuals, due to varying methodologies. These tests' main benefit is to provide a value to evaluate someone's overall health and risk, as well as a biological age which can be used to evaluate treatment or lifestyle improvement.’’
More info for the clinic
As Dr. Pellay explains, biological age tests can predict the rate of aging but results can often lead to more questions: When and who should recommend the test? How should the results be interpreted to achieve the best outcome? How often should retests be done?
Further research is needed for definitive answers. However, the following considerations can help you to make the best use of biological age tests.
The test should be scientifically validated
Not all biological age tests are equal. ‘‘Tests that are not validated by peer-reviewed scientific studies should be avoided,” Dr. Pellay says. “For the ones that do have publications, it is important to see how reproducible they are and on how big of a population this test was validated.’’
The combination of age tests with assessment of clinical biomarkers can yield better outcomes
Changes in certain clinical biomarkers are also associated with aging. In addition, some commercial tests use clinical biochemistry-based algorithms to predict biological age.
Dr. Agarwal notes, ‘’DNA methylation provides a more holistic view of the biological aging process, which may be more useful for long-term intervention strategies. Biomarker-based tests are more actionable in the short term, giving us a clearer insight into how to address metabolic imbalances or cardiovascular risks. In my practice, I have found both to be beneficial. A combined approach may offer a more comprehensive understanding of a patient's aging process and health trajectory.’’
Retest to assess the impact of certain of interventions
‘‘In clinical use, I recommend biological age testing to track the effectiveness of interventions over time,” Dr. Agarwal says. “Testing every 12 to 24 months is reasonable, as it allows enough time to see measurable changes in biological age. However, the frequency can be adjusted based on the patient's baseline health, risk factors, and how aggressively they are pursuing lifestyle or therapeutic interventions.’’
What this means for you
Biological age tests can predict the rate of aging. They can be a motivator to promote preventive actions, especially when combined with the results of clinical biomarkers and other medical assessments. You can educate patients about the tests’ accuracy and potential benefits while encouraging certain lifestyle changes to boost longevity.