Last updated: February 2026 · Written by the Lola Health editorial team

Biological Age Testing Explained: Epigenetics vs Blood Biomarkers

Two approaches, one question: how old is your body really? Here is how epigenetic clocks and blood biomarker algorithms compare — and which biological age test is right for you.

What Is Biological Age?

Your chronological age is the number of years since you were born. Your biological age is how old your body actually is at the cellular and molecular level. The two can differ dramatically.

A 45-year-old who exercises regularly, sleeps well, and manages stress may have a biological age of 38. A 45-year-old with chronic inflammation, poor metabolic health, and sedentary habits may have a biological age of 55. Both are the same chronological age. Their disease risk, functional capacity, and predicted lifespan are vastly different.

Biological age is not a vague concept. It is a measurable quantity, and modern science has developed two distinct approaches to measuring it: epigenetic testing (analysing chemical modifications to your DNA) and blood biomarker algorithms (using standard blood chemistry to estimate phenotypic age). Both are valid, both are backed by large-scale research, and both have trade-offs.

Understanding the difference between these approaches matters because it determines what you learn about your health, how much you spend, and what you can actually do with the results.

Epigenetic Age Testing: How It Works

Epigenetic age testing measures DNA methylation — a chemical process in which methyl groups attach to specific positions on your DNA, called CpG sites. These methylation patterns change in predictable ways as you age, and algorithms trained on large datasets can use them to estimate your biological age with remarkable precision.

The science works like this: your DNA sequence does not change as you age, but the chemical modifications sitting on top of it do. Methylation acts as a regulatory layer, switching genes on and off. As you age, certain sites gain methylation while others lose it. By measuring the methylation status at hundreds of thousands of these sites and feeding the data into a trained algorithm, researchers can calculate a biological age estimate.

The Evolution of Epigenetic Clocks

Epigenetic clocks have evolved through three generations, each more clinically useful than the last:

First generation (2013): Steve Horvath’s landmark clock used DNA methylation at 353 CpG sites to predict age across 51 tissue types. Trained on over 8,000 samples using elastic net regression, it was the first multi-tissue age predictor. Gregory Hannum published a similar clock the same year using 71 CpG sites from blood samples. These clocks track chronological age well but are less sensitive to health outcomes.

Second generation (2018–2019): PhenoAge, developed by Morgan Levine at Yale, incorporated clinical biomarkers into its training — including CRP, glucose, and albumin — making it more reflective of physiological health. GrimAge, developed by Steve Horvath and Ake Lu, predicted mortality more accurately than any prior clock. For every standard deviation increase in GrimAge acceleration, mortality risk increases substantially.

Third generation (2022): DunedinPACE emerged from the Dunedin Multidisciplinary Health and Development Study, which has followed 1,037 people born in New Zealand between 1972 and 1973 for over five decades. Unlike earlier clocks that estimate a static age, DunedinPACE measures the pace of ageing — how fast you are ageing right now. A score of 1.0 means you are ageing at the typical rate. A score of 0.8 means 20% slower. A score of 1.2 means 20% faster. In the CALERIE caloric restriction trial, DunedinPACE was far more responsive to short-term lifestyle changes than GrimAge.

How the Test Is Performed

An epigenetic age test requires a biological sample — typically a blood draw or a cheek swab. The DNA is extracted and processed on an Illumina methylation array, which measures the methylation status of up to 935,000 CpG sites. The raw data is then run through multiple clock algorithms simultaneously.

The most comprehensive commercially available test is TruAge COMPLETE by TruDiagnostic, which holds the exclusive licence for DunedinPACE. A single test returns your intrinsic epigenetic age, extrinsic epigenetic age, pace of ageing (DunedinPACE), telomere length estimation, 11 organ-specific ages, an alcohol impact score, a smoking impact score, and a weight loss response prediction.

Top-tier tests like TruAge achieve over 99% reproducibility (ICC values above 0.97), meaning the same sample tested repeatedly produces nearly identical results. They typically predict chronological age within 2–4 years. Blood-based epigenetic tests are the most accurate; saliva-based alternatives can vary by up to 25 years.

Blood Biomarker Age Testing: How It Works

You do not need a DNA methylation test to estimate your biological age. A growing body of research has shown that standard blood biomarkers — the kind measured in a routine blood test — can also predict biological age and mortality risk with meaningful accuracy.

The most validated blood-based biological age algorithm is PhenoAge, developed by Morgan Levine and colleagues at Yale University in 2018. Using data from the NHANES III study (9,926 adults with over 23 years of mortality follow-up), the researchers identified nine blood markers that collectively predict 10-year survival with 90% accuracy.

The Nine PhenoAge Biomarkers

Collectively, these nine markers capture four major ageing pathways: inflammation (CRP, white blood cells), metabolic function (glucose), organ health (albumin, alkaline phosphatase, creatinine), and immune and haematological status (lymphocyte percentage, MCV, RDW). This is why PhenoAge works — it does not measure one system in isolation. It captures the combined output of multiple ageing processes simultaneously.

How the Algorithm Works

Levine's team used a Cox proportional hazards model, regressing mortality risk against the nine biomarkers plus chronological age. The resulting formula produces a “phenotypic age” — the age at which your biomarker profile would be average in the general population. If your chronological age is 42 but your blood chemistry resembles a typical 48-year-old, your PhenoAge is 48.

The difference between your PhenoAge and chronological age is your phenotypic age acceleration. A positive number means you are biologically older than expected. A negative number means younger. This acceleration score has been validated as an independent predictor of all-cause mortality, cardiovascular disease, cancer, and cognitive decline.

The practical advantage of PhenoAge is that you may already have the data. A comprehensive metabolic panel, complete blood count with differential, and a standalone CRP test provide all nine markers. If you have had a thorough blood test recently, you may be able to calculate your PhenoAge immediately.

Epigenetic vs Blood Biomarker Testing: Head-to-Head Comparison

Which Biological Age Test Should You Choose?

The honest answer: it depends on your goals, budget, and where you are in your health journey.

How to Lower Your Biological Age

Biological age is not fixed. A growing body of peer-reviewed research demonstrates that targeted lifestyle interventions can measurably reduce it. A 2023 study of women following an 8-week methylation-supportive diet and lifestyle programme observed an average reduction of 4.6 years in biological age (from 55.8 to 51.2 years).

Here are the interventions with the strongest evidence:

1. Exercise — both cardio and strength training. This is the single most well-evidenced intervention. Eight weeks of high-intensity interval training has been shown to reduce DunedinPACE scores. Both cardiovascular exercise and resistance training independently improve epigenetic profiles. Aim for at least 150 minutes of moderate-intensity aerobic activity plus two strength-training sessions per week.

2. Eat a Mediterranean-style diet. Rich in polyphenols from olive oil, berries, leafy greens, and oily fish, the Mediterranean diet is consistently associated with younger biological ages. It reduces systemic inflammation (lowering CRP) and supports healthy gene expression. Reducing added sugar by just 10 grams per day has been linked to reversing biological ageing by 2.4 months.

3. Optimise sleep. Consistently sleeping fewer than six hours per night accelerates epigenetic ageing. DNA methylation patterns at sites associated with inflammation, immune function, and metabolic regulation are altered by poor sleep. Aim for 7–9 hours on a consistent schedule.

4. Manage chronic stress. Psychological stress accelerates DNA methylation ageing through cortisol-mediated pathways. Mindfulness practices, meditation, and strong social connections have all been associated with slower biological ageing.

5. Maintain metabolic health. Keep fasting glucose, HbA1c, and insulin in optimal ranges. Insulin resistance is one of the most potent drivers of accelerated ageing and is detectable in blood work years before it becomes clinical diabetes.

6. Reduce chronic inflammation. Monitor hsCRP and address root causes: excess visceral fat, poor diet, chronic infections, gum disease, or autoimmune conditions. Chronic low-grade inflammation — sometimes called “inflammaging” — is a central driver of epigenetic ageing.

7. Limit alcohol and eliminate smoking. Both accelerate DNA methylation ageing significantly. TruAge COMPLETE includes alcohol and smoking impact scores that quantify how much these habits are affecting your biological age. Even moderate alcohol consumption has measurable epigenetic effects.

8. Test, intervene, retest. The value of biological age testing is not in a single number — it is in the trajectory. Take a baseline test, implement changes for 3–6 months, then retest. Blood biomarkers will shift fastest, giving you early feedback. Epigenetic markers follow, confirming whether your interventions are producing lasting molecular change.

Frequently Asked Questions

What is a biological age test?

A biological age test estimates how old your body is at the cellular or molecular level, which can differ significantly from your chronological age. There are two main approaches: epigenetic tests that analyse DNA methylation patterns across hundreds of thousands of sites on your genome, and blood biomarker tests that use standard blood chemistry markers like albumin, creatinine, CRP, and glucose to calculate a phenotypic age. Epigenetic tests are more precise and reproducible, while blood biomarker tests are more affordable and use markers most people already have from routine blood work.

How accurate are epigenetic age tests?

Modern epigenetic age tests like TruAge COMPLETE achieve over 99% reproducibility, meaning the same sample tested multiple times yields nearly identical results. They typically predict chronological age within 2–4 years. Third-generation clocks like DunedinPACE are particularly valuable because they measure the pace of ageing rather than a static estimate, making them more sensitive to recent lifestyle changes. Blood-based epigenetic tests are the most accurate; saliva-based alternatives can vary by up to 25 years.

What is the difference between DunedinPACE and GrimAge?

Both are epigenetic clocks, but they measure different things. GrimAge estimates your biological age as a single number and is strongly correlated with mortality risk. DunedinPACE measures how fast you are ageing right now — a score of 1.0 means you are ageing at the average pace, 0.8 means 20% slower, and 1.2 means 20% faster. In the CALERIE caloric restriction trial, both predicted health improvements, but DunedinPACE was far more responsive to short-term changes. TruAge COMPLETE reports both algorithms.

Can blood tests measure biological age?

Yes. The PhenoAge algorithm, developed by Morgan Levine at Yale, uses nine standard blood biomarkers to estimate biological age: albumin, alkaline phosphatase, creatinine, C-reactive protein, fasting glucose, white blood cell count, lymphocyte percentage, mean cell volume, and red cell distribution width. These markers reflect inflammation, metabolic function, immune health, and organ function. A comprehensive blood test like Peak Insights 70 includes all of these markers, allowing you to calculate your PhenoAge from routine blood work.

Which is better: an epigenetic test or a blood biomarker test?

They serve different purposes and work best together. Epigenetic tests provide a deep, highly reproducible measure of biological age at the DNA level, including pace of ageing and organ-specific ages. Blood biomarker tests are more affordable, more accessible, and provide immediately actionable clinical data — if your CRP is elevated or your glucose is high, you know exactly what to target. For a complete picture, start with a comprehensive blood test to establish your baseline, then add an epigenetic test for the most precise biological age measurement.

How often should I test my biological age?

For epigenetic testing, every 6–12 months is recommended to allow enough time for lifestyle interventions to produce measurable changes in DNA methylation patterns. For blood biomarker testing, every 3–6 months works well because blood markers respond more quickly to changes in diet, exercise, sleep, and stress. Many people take an initial epigenetic test, implement changes based on the results, then retest at 6 months to track their pace of ageing over time.

Can you lower your biological age?

Yes. Multiple peer-reviewed studies have demonstrated that biological age can be reduced through lifestyle interventions. A study of women following an 8-week methylation-supportive diet and lifestyle programme saw an average reduction of 4.6 years in biological age. The most effective interventions include regular exercise (both cardio and strength training), a Mediterranean-style diet, 7–9 hours of quality sleep, stress management, and reducing processed food and sugar intake. Measurable changes can occur in as little as 8 weeks.

What is the Horvath clock?

The Horvath clock, published in 2013 by Steve Horvath at UCLA, was the first multi-tissue epigenetic clock. It uses DNA methylation levels at 353 specific CpG sites to predict biological age, and works across virtually all human tissues and cell types without adjustment. It was trained on over 8,000 samples from 51 tissue types. While groundbreaking, first-generation clocks like Horvath’s primarily track chronological age. Newer clocks like GrimAge and DunedinPACE are better at predicting health outcomes and detecting the effects of lifestyle interventions.