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What is biological age?

Your chronological age counts birthdays. Your biological age measures the actual state of your cells — their DNA methylation patterns, inflammatory burden, and functional capacity. Two people born in the same year can differ by 10–20 biological years. And unlike your birthday, biological age is changeable.

DNA methylation is a chemical process where methyl groups attach to specific positions on your DNA (called CpG sites). These patterns change predictably with aging and disease — like a molecular clock ticking at different speeds in different people. Scientists have mapped these patterns across thousands of individuals to build "epigenetic clocks" that read your body's true age from a single blood draw.

The concept was pioneered by Steve Horvath (2013) who discovered that methylation patterns at 353 CpG sites could predict chronological age with remarkable accuracy. Since then, second-generation clocks have been developed that go beyond age prediction to measure actual health outcomes — including aging pace, disease risk, and mortality.

The three clocks we measure

How they compare

Not all epigenetic clocks measure the same thing. Here's how our three clocks complement each other:

Used together, these three clocks give you the most comprehensive picture of your biological aging available today. DunedinPACE tells you whether you're accelerating or decelerating. GrimAge tells you where you stand in absolute terms. PhenoAge captures inflammatory and metabolic aging that the other two may miss.

How it works

The science behind epigenetic clocks

DNA methylation is one of the most studied epigenetic mechanisms. As we age, certain genes get "silenced" through methylation while others get activated. This process is influenced by everything from diet and exercise to sleep quality and psychological stress.

First-generation clocks (Horvath 2013, Hannum 2013) were trained to predict chronological age from methylation patterns. They're accurate but don't tell you much about health — a healthy 60-year-old and a sick 60-year-old might score similarly.

Second-generation clocks (PhenoAge 2018, GrimAge 2019, DunedinPACE 2022) were trained on health outcomes instead — mortality, disease incidence, and functional decline. These clocks capture biological aging that actually matters for how long and how well you'll live.

The Dunedin Longitudinal Study — which followed 1,037 people born in 1972–73 in Dunedin, New Zealand from birth — provided the groundbreaking data for DunedinPACE. By measuring methylation at multiple ages in the same people, researchers could calculate an individual's actual pace of biological change rather than just estimating a static "age."

Why it matters for longevity

Epigenetic clocks are today's most precise biomarkers for aging and mortality risk. Studies show that elevated DunedinPACE correlates with higher risk of heart disease, dementia, disability, and premature death — independent of other risk factors like smoking, BMI, and blood pressure. 1

A GrimAge that is 5 years older than your chronological age is associated with roughly 25% higher all-cause mortality risk. Conversely, testing biologically younger corresponds to lower risk of cardiovascular events, cancer, and neurodegenerative disease. 2

The landmark Ornish Lifestyle Trial showed that comprehensive lifestyle changes — whole-food plant-based diet, moderate exercise, stress management, and social support — increased telomerase activity by 29% in just 3 months. The 5-year follow-up showed measurable telomere lengthening, the first intervention ever proven to reverse this aspect of cellular aging. 3

More recent research has confirmed that similar interventions can reduce DunedinPACE and GrimAge acceleration. A 2023 randomized trial showed that an 8-week program of diet, sleep, exercise, and relaxation reduced biological age (measured by the Horvath clock) by an average of 3.23 years. 4

What you can do with your results

Once you have your biological age measurements, the actionable steps are clear:

If your DunedinPACE is above 1.0 — you're aging faster than average. Focus on the interventions with the strongest evidence: increase whole plant foods, reduce processed foods, get 150+ minutes of moderate exercise per week, optimize sleep (7–9 hours), and manage chronic stress.

If your GrimAge is older than your chronological age — your accumulated damage is above average. This calls for more aggressive lifestyle optimization and potentially working with a longevity physician to address specific biomarkers.

If both scores are favorable — keep doing what you're doing. Retest in 12 months to confirm your trajectory.

The beauty of epigenetic testing is that it gives you a single, objective metric to evaluate whether your health interventions are actually working — rather than relying on how you feel or how you look.

Know your biological age. A single blood draw. Results in 2–3 weeks. Repeat after 6–12 months to measure your interventions.