How to lower your biological age: what the evidence says

The habits most consistently linked to a younger biological age are the ones linked to a longer, healthier life. Don't smoke, keep a healthy waist, stay fit, build strength and sleep at regular times. Trials that set out to lower biological age directly are few and small, and the best of them found modest effects.

That's less exciting than headlines about reversing your age by years in a few weeks. It's also more useful, because it tells you where effort pays off.

What trials have actually shown

The strongest test so far comes from CALERIE, a randomized trial in which 220 healthy adults without obesity were assigned either to eat 25% fewer calories for two years or to eat as usual. A 2023 analysis of their blood found the calorie-restriction group aged slightly more slowly by DunedinPACE, a DNA measure of the pace of aging, by about 2 to 3%. Other clocks, including PhenoAge and GrimAge, didn't change. The effect was small, and people in the trial cut far less than 25% in practice.

A 2021 pilot trial is often quoted as proof that you can reverse your age by three years in eight weeks. It randomized 43 healthy men aged 50 to 72 to a program of diet, sleep, exercise and relaxation guidance plus supplements, or to nothing. The program group's epigenetic age ended 3.23 years lower than the control group's. But the sample was small, the clock used was one trained to predict chronological age, and two of the authors use the program in their own practice. The journal has since published two corrections to the paper.

There's a measurement problem too. Running the same blood sample through popular epigenetic clocks twice can shift the result by up to 9 years from technical noise alone. A drop of two or three years in a small study can be partly noise.

Habits linked to a younger biological age

A 2021 systematic review pooled 156 studies of what's linked with faster or slower epigenetic aging. Higher body mass index and male sex were significantly linked with faster aging on at least one clock, and faster aging in turn was linked with death, heart disease, cancer and diabetes. These are associations, so they don't prove that changing a habit changes the clock.

Smoking stands out. GrimAge, one of the clocks best at predicting lifespan, includes a DNA estimate of smoking history, because smoking leaves a lasting mark on methylation. Stopping is the largest single change most smokers can make.

Fitness is the other big one, even though it's not usually measured by DNA clocks. In 122,007 adults who took a treadmill test, the least fit quarter were about five times as likely to die over the following years as the fittest 2%. Unlike your DNA, your fitness is easy to retest. See VO2 max and longevity.

Strength matters on its own. A 2022 meta-analysis found 30 to 60 minutes a week of muscle-strengthening activity was linked to a 10 to 20% lower risk of death from any cause, independent of aerobic exercise. See strength training for longevity.

Where to start

Pick the measurement that's weakest for your age and work on that one first, because the gap between poor and average is where research finds the largest differences in risk. For most people, that means one of these.

If you're not active, start with daily walks and build up to regular cardio, including some zone 2 sessions.

If you don't lift, add two short strength sessions a week covering legs, push and pull.

If your waist is more than half your height, steady activity and protein at each meal do more over months than any supplement. See waist-to-height ratio.

If your bedtime varies by more than an hour, a regular sleep schedule is a cheap place to start.

How to know if it's working

Measure something that responds in weeks, not a DNA test that costs hundreds of dollars and moves within its own noise. Resting heart rate, VO2 max, push-ups, a sit-to-rise score and your waist all change with training and can be checked at home.

That's how Ageon works. It turns those measurements into an Ageon Score and an estimated Ageon Age, then lets you try one change at a time and compare your readings with the four weeks before. A difference shows what changed, not proof that the habit caused it. It's an estimate against reference ranges, not a measurement of biological aging, and a lower number isn't proof of rejuvenation. You can see where you stand now with the free biological age calculator.

Talk to your doctor before making big changes to diet, training or medication.