How to Lower Your Biological Age: What the Evidence Supports, Ranked

Biological age is a useful idea that attracts a lot of nonsense. The idea is sound: two people born on the same day can have measurably different physiology, and that difference predicts health outcomes better than the birth date does. The nonsense is what gets sold on top of it.

This page ranks interventions by the size of the effect the research actually supports. It is ordered so that if you only do the first three things, you have captured most of what is available to you.

Tier one: the three that dominate everything else

1. Do not smoke

Large cohort work consistently puts smoking in a category of its own. Analyses across hundreds of thousands of people have put the life expectancy cost of long-term smoking at around a decade. On biological age proxies it is routinely the single largest term in the model. If you smoke, everything else on this page is a rounding error until you stop.

The recovery curve is genuinely encouraging. Most of the excess cardiovascular risk resolves within a few years of quitting, and by roughly a decade the gap has narrowed substantially.

2. Build cardiorespiratory fitness

Fitness is the most powerful thing most people can actively add. A large retrospective cohort of over 120,000 people undergoing treadmill testing found a graded relationship between measured cardiorespiratory fitness and all-cause mortality with no upper limit of benefit, and the gap between the lowest fitness group and the rest was large enough to rival established disease risk factors.

What matters is the practical translation. Meeting the 150 minute guideline is the floor. The measurable gains keep appearing as you move toward 300 minutes a week, and adding two sessions of resistance work protects the muscle and bone that decide how the last two decades of your life actually feel.

3. Reduce central adiposity

Waist measured against height is a better ageing signal than BMI, because BMI cannot tell muscle from fat and cannot see where the fat sits. Visceral fat is metabolically active tissue that drives chronic low-grade inflammation, and inflammation is one of the mechanisms that biological age clocks are picking up.

The commonly used boundary is a waist-to-height ratio of 0.5. Our biological age estimator uses that boundary directly, and you can see the exact weight it carries on the methodology page.

Tier two: large, consistent, frequently ignored

4. Sleep in the seven to eight and a half hour band

The relationship between sleep duration and mortality is U-shaped, not linear. A widely cited meta-analysis covering more than a million participants found elevated risk at both short and long durations. Short sleep is the more common problem and the more actionable one.

Quality matters alongside duration. Eight hours of fragmented, non-restorative sleep does not deliver what seven solid hours does.

5. Watch resting heart rate as a free biomarker

Resting heart rate is the cheapest longitudinal marker you have, and most people already own a device that tracks it. Cohort work has associated each 10 bpm increment above the low range with a meaningful rise in all-cause mortality. It also responds to training, which makes it a genuine feedback signal rather than just a score.

6. Eat mostly food you would recognise as food

The dietary literature is noisy at the level of individual nutrients and consistent at the level of patterns. Whole-food dominant patterns with a high plant fraction outperform ultra-processed dominant patterns across essentially every cohort that has looked. You do not need to pick a camp between Mediterranean and any other named diet to capture most of the benefit.

Tier three: real, smaller, worth doing

• Alcohol. The protective-drinking story has not survived better study design. Treat alcohol as a cost you choose to pay, and keep the amount low.
• Chronic stress. The variable that matters is recovery, not intensity. Sustained load without downtime shows up in inflammatory and metabolic markers.
• Social connection. Consistently associated with mortality at effect sizes that surprise people, and almost never on a supplement company's list.
• Dental and metabolic maintenance. Unglamorous, well evidenced, cheap.

Tier four: where supplementation honestly sits

This is the part most longevity sites get wrong, usually on purpose. Here is the straight version.

Alpha-ketoglutarate is a real molecule with a real role. It sits in the citric acid cycle, it acts as a cofactor for a family of dioxygenase enzymes that includes the TET enzymes involved in DNA demethylation, and there is evidence that circulating levels fall substantially with age. That is a plausible mechanism, and plausible mechanisms are where good interventions start.

Plausible is not proven. Here is the actual human evidence base as it stands.

There is also observational cohort work associating supplement use with biological age markers in healthy populations. Association studies of that design cannot separate the supplement from the person who chose to take it. People who buy longevity supplements also tend to sleep, train and eat differently from people who do not.

Our full read of the literature, including what would need to happen for the evidence to become convincing, is on the AKG evidence page.

What to do this week

1. Run the estimator and note your three largest contributors.
2. Pick the single largest one. Not all three.
3. Book a standard blood panel if you have not had one in two years. Real biomarkers beat any self-report model, including ours.
4. Re-run the estimator in ninety days against the same inputs and see what moved.

Common questions