Glossary

Reduce the load rather than chase the repair: sun sensibly, do not smoke, keep alcohol modest, sleep. The single most useful thing here is not a supplement but screening — finding what went wrong early, which is the whole point of the Bridge of Prevention.

The lesson of the last twenty years is that blanket antioxidant supplementation does not help and can blunt the benefits of exercise. Eat the colourful plants, train, sleep, avoid the obvious insults. Do not megadose vitamins to fix this.

Length is mostly inherited, and lengthening it on purpose is not something to chase — the same machinery is what cancers exploit. What is well supported: sleep, exercise, not smoking, and lower chronic stress track with slower shortening. Be sceptical of anything sold as a telomere lengthener.

Nothing you can buy switches it on safely: most cancers use the same machinery to keep dividing, which is why it is watched so closely. What is well supported is slowing the wear — sleep, exercise, not smoking and lower chronic stress. As a gene therapy it is experimental.

Epigenetic age tests have become widely available and remain noisy — useful as a trend over years, not as a single reading. Partial reprogramming, which resets these marks, is the most exciting thing in the field and is not yet a human therapy.

Nothing you can do, and that is the entry. This is the frontier: it is in animals and in early company pipelines, and the risk it has to clear is cancer, because a cell that forgets what it is, is a tumour. It is on this page because it is the idea most likely to change what the rest of the page means — not because there is anything to take.

The honest answer is that the clocks are better at measuring than at being moved. They respond to the things that already have hard outcome data behind them — exercise, sleep, not smoking, body composition — and a few small trials have shown a year or two of reversal. On consumer tests: the same sample sent twice can come back with different answers, so read one result as a rough position and a trend over years as the number that means something.

Sleep, because clearance in the brain runs hardest then. Exercise. Enough protein, spread through the day rather than in one sitting. Heat exposure switches on the chaperone proteins that do this work.

Going without food for a stretch is the strongest everyday lever — time-restricted eating or a longer fast. Hard exercise does it too. Coffee, green tea and olive oil each nudge it. Rapamycin is the most convincing pharmacological route and remains a prescription drug under study.

For most people, time-restricted eating and the occasional fasting-mimicking cycle capture most of the benefit without the cost. Sustained severe restriction carries real risks — muscle and bone loss especially — and is a poor trade after sixty.

Periods without food and without constant protein. This one has a real tension in it: the same signal that drives ageing also builds the muscle that keeps you alive after seventy. Most people over fifty need more protein, not less, and the cycling matters more than the average.

Exercise is the most reliable activator anyone has found. Metformin and berberine act here too; metformin’s longevity effect in healthy people is still being tested, and the large TAME trial that would settle it has not yet reported.

Muscle is the largest glucose sink you own, so resistance training matters as much as diet. Walking after meals works. A continuous glucose monitor worn for a few weeks is one of the few pieces of consumer tech that reliably changes behaviour, because you see your own response rather than a general rule.

This is where the story has changed most since 2023. NAD+ precursors reliably raise NAD+ in blood; what they have not yet shown is that this makes healthy people live longer or better. Treat the supplement claims with more caution than the 2023 version of this page did. Exercise and sleep remain the unglamorous route.

Zone 2 endurance work builds new ones; high-intensity intervals improve the ones you have. Doing both beats doing either. Supplement evidence here is modest next to the training effect.

Exercise is the proven way to turn it up, endurance work especially; cold exposure does it to a lesser degree. Raising it with gene therapy is experimental.

Clearing them extends healthy life in mice, which is why senolytics attracted so much attention. Human trials so far have been small and the results mixed. This is a genuinely promising area that is not yet a thing you should be dosing yourself for.

Exercise, sauna, cold exposure, fasting. Sauna has the strongest population data behind it. Cold has become fashionable well ahead of its evidence — it feels excellent and the long-term claims are thinner than the enthusiasm suggests.

Nothing yet reliably rebuilds a reserve in a human. Protecting it is well established: resistance training keeps the satellite cells in muscle active, sleep and control of chronic inflammation reduce the drain. Stem cell transplants are standard care in a few blood cancers and are not an anti-ageing treatment — clinics selling infusions for ageing are selling ahead of the evidence, and some of what they sell is dangerous.

This is the one on this list with the least ambiguity and the most leverage. Resistance training at least twice a week, enough protein, and vitamin D if you are low. Grip strength and how fast you can stand up from a chair predict how the rest of your life goes better than most blood tests.

Exercise raises it modestly, and so does looking after your kidneys, which is where most of it is made. There is nothing to buy: klotho does not survive being swallowed, and injected forms are in early trials. What it is genuinely useful for today is as a marker — something to measure rather than something to move.

Sleep is both a cause and a cure, and it is the first thing to fix. Exercise raises cortisol briefly and lowers the baseline. Breathwork and meditation have real if modest effects on the hormone and larger ones on how the stress is experienced. Connection matters more than most people expect — loneliness is a chronic stressor with its own mortality signal. And the most useful move is rarely a technique: it is removing one of the things that is ringing.

Sleep, weight, muscle, oral health, and treating the obvious sources. Omega-3s have decent evidence. This is also one of the few processes where a simple blood test — high-sensitivity CRP — tells you something useful and cheap.

Plant variety is the strongest and dullest answer — the number of different plants in a week beats any supplement in the data there is. Fermented foods raised diversity and lowered inflammatory markers in a controlled Stanford trial. Fibre feeds what is already there. Probiotic capsules are far weaker than their marketing; most strains pass straight through. Antibiotics cost diversity for months, which is a reason to need them rather than to want them.