What is biological age (and why it matters)?

Biological age is not just the number of birthdays you've had. Instead, it reflects the wear and tear on your body, essentially how old your cells and tissues appear based on their current health, as opposed to how long you've lived.

Someone who is 40 years old by calendar years could have a biological age closer to 30 (if they're exceptionally healthy), or conversely 50+ (if their body shows signs of accelerated ageing). In short, chronological age is "years lived", whereas biological age is "body years", an estimate of your body's condition and risk of age-related issues.

This distinction matters because biological age is often a better predictor of health outcomes – like your risk of chronic diseases or even lifespan – than chronological age. By knowing your biological age, you get a clearer picture of your overall health and how effectively (or ineffectively) you're ageing.

For example, research has shown that individuals of the same chronological age can have very different health trajectories. In one study, 65-year-olds with a lower biological age had a median life expectancy about 9 years longer than those with a higher biological age.

In another analysis, each 1-year increase in biological age (as measured by the method we use at Vively) corresponded to roughly a 9% higher risk of death from all causes.

These findings underscore why measuring biological age is so valuable: it can identify people at higher risk earlier, even if they haven't been diagnosed with any disease.

In other words, biological age is an early warning signal – a way to gauge if your body is ageing faster than it should so you can take action to improve your health. And the good news is that unlike your birth date, biological age is changeable: improve your lifestyle and health, and you can potentially slow down or reverse your biological ageing.

Vively’s evidence-based approach: the Levine PhenoAge Algorithm

At Vively, we calculate your biological age using a scientifically validated method known as the Levine Phenotypic Age (PhenoAge) algorithm. This method was developed by Dr. Morgan Levine and colleagues at Yale University in 2018 as a way to determine biological age using routine blood tests.

Rather than relying on expensive genetic tests or guesswork, the Levine PhenoAge approach harnesses 9 standard biomarkers from a blood test (plus your chronological age) to estimate how old your body truly seems. The goal of Levine’s team was to make biological age accessible and practical, prioritising the use of common lab measures over high-tech precision, without sacrificing too much accuracy.

In simple terms, PhenoAge is a mathematical model that takes key health indicators from your blood (things like your glucose, immune cell counts, liver/kidney function markers, etc.) and crunches them into a single age number. If your biological age comes out higher than your actual age, it suggests your body has more wear and tear (aging faster than normal). If it's lower, you may be healthier or “younger” than your calendar age would suggest.

This algorithm is built on extensive research: Dr. Levine’s team analyzed large population datasets to identify which combination of blood measurements best predicts a person’s risk of death and disease. The result was PhenoAge – a formula that converts those blood values into an equivalent age (the age of average people in the population who share your risk profile).

Why did we choose Levine PhenoAge for Vively?

Because it's backed by solid science and real-world data. Studies have found that PhenoAge is highly predictive of important health outcomes. It outperforms many traditional metrics (and even some cutting-edge genetic ageing tests) in indicating who is at higher risk for things like heart disease, cancer, diabetes, or early mortality.

Crucially, it uses routine biomarkers that any standard lab can measure, which means it's affordable, accessible, and reliable for our members. In short, Vively’s biological age calculation isn’t a gimmick or a proprietary black box – it’s a research-proven method used in longevity science and validated in peer-reviewed studies.

We believe this fosters transparency and trust: you can have confidence that your bio-age number is grounded in rigorous scientific evidence, not hype.

Ready to see your own results? Take Vively’s simple blood test today and discover your Biological Age alongside 50+ key health markers: Start your test.

The 9 biomarkers that power your biological age

To calculate your biological age with the PhenoAge model, Vively looks at nine specific biomarkers from your blood test. Each of these markers gives insight into a different aspect of your health and ageing.

Together, they provide a holistic snapshot of how well your body is functioning. Here are the nine biomarkers we use and why each one matters in gauging your biological age:

1. Albumin: A protein made by the liver. Healthy levels of albumin suggest good nutritional status and liver function, whereas low albumin can indicate chronic inflammation or malnutrition. In ageing, lower albumin is often seen in frailty or chronic disease states.
2. Creatinine: A waste product filtered by your kidneys. It reflects kidney function and muscle mass. If creatinine is elevated, it may signal impaired kidneys or muscle breakdown. Poor kidney function can accelerate health decline, making this a key age-related marker.
3. Glucose (Fasting Blood Sugar): Higher fasting glucose indicates poorer metabolic health and potential insulin resistance. Elevated blood sugar is linked to diabetes risk and can contribute to faster aging processes. Essentially, it gauges how well your body handles sugar – a critical factor in longevity.
4. C-Reactive Protein (CRP): CRP is a marker of systemic inflammation. When CRP is high, it means your body has higher inflammation levels, which are associated with many chronic conditions (heart disease, obesity, etc.) and accelerated aging. Inflammation is like a “rust” on the body’s systems, so it heavily influences biological age.
5. Lymphocyte Percentage: This is the percentage of white blood cells that are lymphocytes, a key part of your immune system. A low lymphocyte percentage can suggest stress on your immune system or chronic stress/illness, whereas a balanced level indicates robust immune function. Immune health is crucial for longevity, making this a useful ageing indicator.
6. Mean Cell Volume (MCV): MCV measures the average size of your red blood cells. Abnormal MCV (too low or high) can point to nutrient deficiencies like iron, B12, or folate. Proper nutrient status is important for maintaining healthy cells; deficiencies can reflect or contribute to biological aging.
7. Red Cell Distribution Width (RDW): RDW is the variation in size of your red blood cells. A higher RDW means there's more variability, which is often linked to issues like inflammation, vitamin deficiencies, or other stresses on the body. Studies have found higher RDW correlates with higher mortality – it's an indirect marker of something “off” in blood cell production, common in older or less healthy individuals.
8. White Blood Cell Count (WBC): This is the total count of white blood cells, which are your immune cells. If WBC is very high or very low, it can indicate infection, inflammation, or immune system dysregulation. Chronic mild elevation can signal ongoing inflammation in the body. Since chronic inflammation accelerates ageing, WBC count plays a role in the algorithm.
9. Alkaline Phosphatase (ALP): An enzyme related to liver and bone health. Elevated ALP can point to liver stress or bone turnover issues. It’s included because liver function tends to decline with unhealthy ageing, and liver enzymes like ALP can reflect broader metabolic health.

Each of these biomarkers is like a puzzle piece – on its own it tells you about one facet of health, but when combined through the PhenoAge formula, they yield a surprisingly comprehensive picture of your body's biological age. By inputting all nine values (plus your actual age) into the algorithm, Vively computes your Phenotypic Age, which we report as your Biological Age.

We also leverage the algorithm to estimate a 10-year mortality risk percentage (essentially, a risk score) alongside your bio age – this comes directly from Levine’s published model, which was calibrated to population mortality data. This risk estimate is another way to contextualise your biological age: for instance, a Biological Age of 60 (when you are 50 years old) corresponds to a higher 10-year risk of death than a Biological Age of 40 would at the same chronological age. While the exact percentage has some uncertainty for any individual, it's a useful benchmark and reinforces why improving your biomarkers can literally extend your life.

Important: These nine markers are all routine tests you could get during a normal blood work-up. There’s no exotic procedure needed. This means most people can easily obtain the data needed – either from recent blood test results or via a simple lab test we can help arrange. 

By using such accessible biomarkers, Vively's Biological Age calculation stays grounded in everyday health data, so you can track it without hassle and see how it changes as you improve your lifestyle.

Built on science, backed by research

Vively’s biological age calculation isn’t just our idea – it’s grounded in extensive ageing research. The Levine PhenoAge model has been scientifically validated in multiple studies and populations. Here are a few key findings that highlight its credibility and power:

Predicts mortality and longevity

The phenotypic age measure is strongly associated with risk of death. In a nationally representative U.S. study, Phenotypic Age proved highly predictive of 10-year mortality, even after accounting for people’s chronological age.

In fact, one publication noted that Phenotypic Age could predict whether someone would die within a decade with an accuracy (AUC) of about 0.88, outperforming any single biomarker or even chronological age alone.

To put it plainly: your bio age number carries real weight – a higher number corresponds to higher risk. For instance, each 10-year increase in Phenotypic Age was linked to a 51% increase in mortality risk in heart patients, and those with a higher bio age tended to have more age-related diseases.

Conversely, having a lower biological age than your actual age is a favourable sign associated with longer life expectancy.

Captures disease risk beyond age

What makes biological age especially useful is that it captures the risk of chronic diseases better than chronological age. Researchers found that Phenotypic Age was robustly associated with not only all-cause mortality but also cause-specific mortality (like cancer, heart disease, etc.) across diverse subgroups of people.

Even among people who were clinically healthy (no diagnosed diseases, normal BMI), a higher biological age still signalled a higher risk of future illness or death. This means the bio age metric is picking up subtle signs of deteriorating health that might not yet have a diagnosis label. It gives a more nuanced view of your health status, acting as an early indicator of potential problems.

Better than high-tech clocks (in key ways)

You may have heard of DNA methylation “epigenetic clocks” or telomere tests purporting to measure biological age. Those are exciting technologies, but studies (including Levine’s work) have shown that blood-chemistry-based ages like PhenoAge correlate more strongly with actual health outcomes than some genetic ageing markers.

The likely reason is that these 9 biomarkers reflect multiple major ageing processes – inflammation, metabolic and organ function, and immune status – basically the end result of many genetic and environmental factors. Epigenetic clocks are great at estimating chronological age itself, but when it comes to telling if someone is ageing well or poorly (beyond what their birth age says), phenotypic measures tend to be more informative.

In short, Vively’s approach is aligned with what current gerontology research finds most practically useful for gauging healthspan.

Validated in different populations

The algorithm was originally derived from U.S. population data (NHANES studies), but its effectiveness has been replicated elsewhere as well. Subsequent research has applied PhenoAge in various groups.

For example, studies on hospitalised patients, different ethnic groups, and those with specific conditions found that a higher biological age consistently correlates with worse outcomes or frailty, proving its generalisability. It’s also been used in clinical trials and wellness programs as a metric to track whether interventions (like lifestyle changes or medications) are improving patients’ ageing profiles.

This breadth of use gives us confidence that the measure is reliable and meaningful for people of all walks of life.

By basing our calculations on this well-vetted method, Vively ensures that when we tell you your biological age, we're giving you a real, evidence-based health insight – not a marketing gimmick. We provide citations to the underlying research (for those who love the nitty-gritty details) because we're committed to transparency and scientific integrity.

Knowing that your Biological Age is derived from a peer-reviewed formula can hopefully give you extra peace of mind in trusting the number and using it to guide your health journey.

What can you do with this information?

Learning your biological age is empowering. It’s not meant to scare you – it's meant to inform and motivate you. If you discover that your biological age is higher than you'd like, remember: biological age is not fixed. It can be improved with the right changes. In fact, that’s a big reason we include it in our Vively program to help tailor and inspire your personal health plan.

Research shows that adopting a healthier lifestyle can slow down or even reverse aspects of biological ageing. For example, a 2023 analysis found that people with excellent cardiovascular health habits (the AHA “Life’s Essential 8” which includes diet, exercise, not smoking, healthy weight, good sleep, and controlled blood pressure, cholesterol, and glucose) were on average 6 years younger biologically than those with poor habits.

In practical terms, things like eating a nutritious diet, staying active, managing stress, getting quality sleep, and controlling your blood sugar and blood pressure can all contribute to a younger biological age.

Each of those positive changes chips away at risk factors that are reflected in the biomarkers (for instance, exercise and weight loss can lower your CRP and fasting glucose; a healthy diet can improve cholesterol and nutrient levels, affecting MCV/RDW; stress reduction can normalise immune cell counts, etc.). Over time, these improvements will be captured in a better PhenoAge score.

At Vively, we use your Biological Age as a compass for your health journey. It gives us (and you) a tangible number to track as you implement changes. Alongside other metrics (like glucose patterns from your CGM, cholesterol levels, etc.), it helps personalise your recommendations. If your bio age is higher than ideal, we might focus on strategies to reduce inflammation or improve metabolic health.

If your bio age comes down after a few months of interventions, that's a sign that your body is responding positively – you’re effectively youthing in a way! Many of our members find this more encouraging than just watching the scale or step count, because it encapsulates multiple aspects of health into one measure. It’s like seeing the overall grade on your health report card improve.

We recommend re-checking your biological age periodically to monitor progress. Biology isn't static – so tracking it over time is key. Some people do a check every 6-12 months. Others might align it with their routine blood work schedule. Whenever you repeat it, you can directly see the impact of your lifestyle changes or treatments.

A drop in biological age (getting closer to or below your calendar age) is a strong indicator that you’ve lowered your risk profile. Even maintaining your bio age as you get chronologically older means you’re slowing aging. On the flip side, if the number worsens, it can be an early nudge to refocus on health before any serious condition develops.

Wrapping up

By calculating your biological age with the Levine PhenoAge method, Vively provides you with a meaningful, actionable insight into your health. This isn’t just about a single number – it's about understanding your body better.

A younger biological age can reinforce that your current lifestyle is on the right track, while an older biological age can serve as a wake-up call and a source of motivation to prioritise your health. Most importantly, knowing your biological age helps build trust that the steps you take with Vively (be it improving your diet, using our continuous glucose monitoring, adjusting your sleep or stress, etc.) are actually making a difference that you can measure.

In summary, Vively calculates your Biological Age using a research-backed algorithm leveraging nine key blood biomarkers. This evidence-based approach allows us to turn ordinary lab results into a powerful lens on your wellbeing – one that has been shown to predict longevity and disease risk better than the calendar on your wall.

It’s an approach rooted in education and transparency: we want you to understand what’s behind the metric and to feel confident in its significance. By integrating this with our personalised coaching and data-driven insights, we aim to not only add years to your life but life to your years. Your biological age is a number you have the power to change – and Vively is here to guide you in making that number as low as possible so you can enjoy a longer, healthier future.