Learn about aging clocks

The difference between chronological and biological age, why it matters, and what science actually knows (and doesn't know) about measuring it.

The 12 biological processes that drive aging — and a framework for understanding what biological age tests actually measure.

From Horvath's pan-tissue clock to DunedinPACE: how DNA methylation patterns are used to estimate biological age, and why different clocks give different answers.

Some clocks estimate how old your biology looks. Others predict health outcomes. Others measure how fast you are aging right now. Here is how to tell them apart — and which type is useful for what.

A 2025 Nature Medicine study trained an AI model on 9.7 million patients' clinical records and found meaningful aging signal in the markers already in your annual blood panel. What the research shows — and what it does not yet justify.

A biological age score is a model output, not a health outcome. Why group-level validation doesn't guarantee individual reliability, what technical vs. biological repeatability means, and why a changed score isn't yet a health benefit.

The answer is more nuanced than most marketing suggests. Evidence-based guidance on testing intervals, measurement precision, and why consistency matters more than frequency.

WHO's framework for the physical and mental capacities a person can draw on — how it differs from functional ability, and from the biological-age scores this site evaluates.

What AI-based, visual, and wearable aging proxies can tell you — and where their limits are. How non-molecular methods compare to established epigenetic and glycomic clocks.

How physical activity affects epigenetic clocks, inflammatory markers, and phenotypic aging scores. A balanced look at what the science supports — and where the gaps remain.

Meet researchers worth following on how we age, organized by the questions their work helps answer, with the commercial ties we found stated plainly.