Rhonda Patrick, Ph.D.

Welcome back to the podcast.

Today I'm joined by Dr. Steve Horvath, one of the most influential scientists in the biology of aging and a true legend in the field of longevity science.

Steve is best known for pioneering the Horvath epigenetic clock, which is a breakthrough that really helped make biological aging measurable through DNA methylation.

Before this work, aging was something mostly described through disease, frailty, organ decline, or simply just the passage of time.

Steve's work really helped transform aging into something we could begin to quantify at the molecular level across different tissues, across different disease states, and across interventions.

That contribution is hard to overstate.

Epigenetic clocks are now central to some of the biggest questions in aging science, whether we can measure the rate at which someone is aging, whether lifestyle or medical interventions can slow that rate, and whether aspects of cellular age can actually be reversed.

In this episode, Steve and I get into all of that.

We talk about what biological aging clocks can tell us and what they cannot.

This is important because biological age is not just one number.

Some epigenetic clocks are more sensitive to inflammation, immune function, metabolic health, smoking history, or long-term stress exposure.

Others are better at estimating our mortality risk, disease risk, or the current pace at which someone is aging.

And once we establish that foundation, we move into the questions that people actually want answered.

We discuss whether lifestyle changes can reverse age acceleration, whether these clocks can predict when someone will die,

and why a younger biological age does not necessarily mean you have added years to your life.

We also get into some of those more practical and provocative areas of longevity science, including whether caloric restriction can slow the pace of biological aging, whether omega-3s, vitamin D, or a daily multivitamin can shift aging clocks, what type of exercise appears most effective for slowing epigenetic aging, whether vegetables matter more than exercise in some methylation data sets,

whether red meat shows up as an aging signal, how sleep disruption and social connection appear on biological aging clocks, whether GLP-1 drugs like semaglutide may reverse epigenetic aging signals.

how to interpret consumer biological age tests without overreaching, why two epigenetic age tests may even give different answers, whether AI will build better aging clocks, and one of the most fascinating frontiers in the field, partial reprogramming,

the possibility that cells may be made biologically younger without losing their identity.

We also talk about what aging clocks miss because even if a clock moves in a favorable direction, that does not mean every single hallmark of aging has been repaired.