Stem-cell exhaustion, read in the blood: what clonal haematopoiesis reveals
As blood stem cells age, mutant clones take over. By the eighth decade this shows up in about one person in ten — and it tracks with higher mortality and heart disease.
Longevity & Aging
Healthspan, aging biology, and the claims the anti-aging market makes.
Frequent sauna use tracks with longer life. No trial has shown it causes it
Finnish cohorts link regular sauna bathing to lower cardiovascular and all-cause mortality, with a dose-response. But these are observational studies, and no randomised trial has tested sauna against death.
What keeps you mobile in old age? A trial shows exercise prevents disability, modestly
Losing the ability to walk is a turning point in later life. In a large randomised trial, structured activity cut the rate of major mobility disability — evidence that movement protects independence, read honestly.
Mitochondrial decline is a real part of ageing. The pills aimed at it mostly disappoint.
Failing mitochondria are one of ageing's core hallmarks, and human trials of mitochondria-targeted compounds show flickers of benefit — but the strongest endpoints keep coming back null.
Does treating hearing loss protect the ageing brain? The big trial complicates it
Observational studies tie hearing loss to faster mental decline. But the first large randomised trial found no overall benefit from hearing aids over three years — with a signal of help only in higher-risk older adults.
The 'information theory of aging' is a bold idea resting almost entirely on mice
A prominent hypothesis holds that ageing is lost epigenetic information that can be reset. The mouse experiments behind it are striking, but no human study shows resetting the epigenome extends life.
Clearing worn-out 'senescent' cells rejuvenates mice. In humans the trials are tiny
Cellular senescence is a well-evidenced driver of ageing in animals. The first human trials of senolytic drugs that clear these cells are real but tiny, early, and nowhere near proving longer healthy life.
Can you still build muscle after 60? The strength comes fast; the bulk comes slowly
Even frail people in their 80s and 90s roughly doubled their strength in ten weeks of training. But muscle size barely moved — the honest expectation is a big gain in function and a modest one on the scale.
Does lowering blood pressure protect the ageing brain? The dementia result missed
A landmark trial pushed blood pressure hard and cut mild cognitive impairment — but its headline dementia result fell short of significance after the study stopped early. The pooled trial evidence is real, and modest.
GDF11 was called young blood's rejuvenation factor. A rival lab could not reproduce it.
Mouse studies claimed one circulating protein reversed ageing of the heart, muscle and brain. A second team found the muscle effect ran the opposite way — and no human trial has ever tested it.
A daily aspirin did not extend healthy old age, and raised the risk of serious bleeding
ASPREE randomised 19,114 healthy older adults to low-dose aspirin or placebo. It made no difference to disability-free survival, and modestly raised deaths and major haemorrhage.
Is fitness the top longevity marker? Being unfit beat smoking as a death risk
A large treadmill cohort found the least-fit adults had about five times the death rate of the fittest — a bigger risk than coronary disease, smoking or diabetes. But it measures a state, not a lever.
Is sitting shortening your life? In a million people, enough activity cancelled the risk.
A harmonised meta-analysis of over a million adults found high sitting time raised mortality — but about 60 to 75 minutes a day of activity erased that risk. Being inactive, not the chair itself, did most of the damage.
Does muscle mass matter for ageing? Strength predicted survival; muscle size did not
In 2,292 older adults, weak quadriceps tracked with higher mortality — but muscle size, measured by CT and DXA, did not. The finding reshaped how sarcopenia is defined and moved the target from bulk to strength.
Does metformin extend life? Diabetics on it outlived non-diabetics in one cohort
A widely cited cohort found people with diabetes on metformin outlived matched non-diabetic controls. It fuelled the TAME anti-ageing trial — but the human signal is observational, and TAME is not running.
'Longevity escape velocity': what the mortality data say about the claim
The idea that anti-ageing advances will soon add more than a year of life for every year that passes is popular in longevity circles. National death records point the other way.
Klotho: strong longevity genetics, no human anti-ageing therapy yet
A protein named after a Greek fate slows ageing in mice and sharpens memory in old monkeys. In people the evidence is a gene variant you are born with, not a treatment.
The free-radical theory of ageing is elegant. The antioxidant pills failed the test
For 70 years the idea that oxidative damage drives ageing justified a supplement industry. Large randomised trials found antioxidant pills do not extend life, and some raise mortality.
Does protein intake matter for ageing? The answer flips depending on how old you are
One cohort tied high animal protein in midlife to higher mortality, yet found the opposite after 65. Guidelines urge older adults to eat more, and plant protein looks best. No trial proves a lifespan effect.
Does the Mediterranean diet make you live longer? The trial and the cohorts disagree
Observational studies robustly link the diet to lower mortality. The best randomised trial measured fewer heart attacks and strokes, and the strongest review finds the evidence for a survival benefit weak.
Do optimism and a sense of purpose really add years to life? The evidence, honestly
Large cohorts link higher optimism and a stronger sense of purpose to longer life and lower mortality, in a dose-dependent way. But the studies are observational, and no trial has proved the causal arrow.
Glycation and AGEs: real ageing chemistry, oversold as a diet you can hack
Sugars bond to proteins to form advanced glycation end products that accumulate with age and stiffen tissue. Low-AGE diets nudge metabolic markers, but no trial shows they slow ageing.
Does sleep affect how long you live? Both too little and too much track with dying sooner
Meta-analyses of more than a million people find a U-shaped link between sleep duration and death, lowest around seven hours. But this is observational, and reverse causation is the hard part to rule out.
The immune system ages on its own — and the fix that works is a better vaccine
Immunosenescence, the age-related decline of immunity, is real: the thymus shrinks and the T-cell repertoire narrows. The proven counter is not a supplement but vaccines engineered to force a response.
Hormesis is real for exercise. It is oversold for almost everything else
The idea that a little stress makes the body stronger is sound biology, and the best-evidenced example is ordinary exercise. Stretched to cold, fasting and antioxidant pills, the human evidence thins fast.
Autophagy explained: a real ageing mechanism, an unproven human lever
Autophagy is the cell's self-clearing recycling process, and it wanes with age. Fasting, spermidine and rapamycin switch it on in lab animals — whether that extends human life is unproven.
Inflammaging is real and measurable. Whether lowering it extends healthy life is unproven.
The rise in chronic, low-grade inflammation with age is genuine, and researchers built a clock from it. The one large trial that lowered inflammation for a hard outcome treated heart disease, not ageing.
A Welsh birthday cutoff gave the best evidence yet that a shingles jab may delay dementia
Eligibility set by exact date of birth created a natural experiment. Vaccinated people had a 20% lower relative risk of dementia over seven years. It is one striking study, and it tested the older live vaccine.
Does memory loss always mean dementia? No — but it is not always nothing either
Forgetting a name is not dementia, and a third of people diagnosed with mild cognitive impairment revert to normal. But that diagnosis still carries weight: risk of dementia stays elevated even in those who bounce back.
Omega-3 slowed biological-age clocks in a trial, by a few months over three years
The DO-HEALTH sub-study is the first randomised evidence that a supplement can nudge DNA-methylation ageing clocks. The effect was tiny, and the parent trial found no benefit on health outcomes that matter.
Growth hormone and IGF-1: the longevity trade-off behind an anti-ageing pitch
The signalling that builds muscle in youth appears to speed ageing and cancer. People with lifelong GH deficiency avoid both — and GH given to healthy older adults raises harms without extending life.
Run the same sample through an ageing clock twice and it can differ by years
Epigenetic clocks estimate a 'biological age' from DNA methylation. A 2022 study found technical noise alone could shift the result by up to 9 years between replicates of the same sample.
What two years of calorie restriction did to healthy humans in the CALERIE trial
The only long randomised trial of calorie restriction in non-obese adults improved cardiometabolic risk and modestly slowed one measure of biological ageing. Participants never hit the 25% target.
Spermidine and longevity: a striking survival link, and a trial that fell flat
Dietary spermidine tracks with markedly lower mortality in one population study. The first year-long randomised trial of a spermidine supplement found no effect on memory.
Blue Zones began as validated demography. The data behind them is now contested.
The Sardinian 'Blue Zone' was a real, carefully validated finding. A separate line of work argues the world's longevity hotspots track missing birth records and old-age poverty — not diet.
'Young blood' for ageing: what parabiosis and plasma exchange actually show
Infusing plasma from young donors is sold as rejuvenation. The mouse work suggests diluting old blood may matter more than adding young blood — and regulators warn the paid infusions have no proven benefit.
We added years to life faster than health to those years. The gap is widening.
The dream was 'compression of morbidity' — sickness squeezed into a short window before death. Across 183 countries the healthspan–lifespan gap instead grew to 9.6 years, and to 12.4 in the US.
The fasting-mimicking diet: what its human trials measured, and what they didn't
Five-day fasting cycles improve risk markers and one 'biological age' estimate in small trials. No human study has yet shown the diet prevents disease or extends life.
How fast you walk predicts how long you live. It is a mirror, not a dial.
In 34,485 older adults, each 0.1 m/s of walking speed tracked with better survival. At age 75, predicted 10-year survival ran from 19% to 91% across the range — but speed reflects health, not the reverse.
The best-evidenced longevity intervention is exercise, and most of it is cheap
No pill in the anti-ageing market has mortality data like physical activity. The largest cohorts show most of the benefit arrives at half the recommended dose, and more brings diminishing returns.
The 'hallmarks of aging' organise the field. They are a checklist, not a theory.
A 2013 paper named nine hallmarks of aging; a 2023 update made it twelve. The framework is the field's shared map — but critics argue it describes ageing without explaining it.
Longevity genetics: what FOXO3, APOE and centenarian studies establish
Very long life carries real genetic signals — the APOE gene most robustly, FOXO3 in some populations. But pedigree studies put the true heritability of human lifespan well below 10%.
What NMN and NR longevity supplements actually do in human trials
The NAD+ precursors sold to slow ageing reliably raise NAD+ and are well tolerated. What the randomised trials do not show is a benefit to muscle, metabolism or how old you are.
Resveratrol and sirtuins: what the human evidence shows against the hype
It extends life in yeast, worms and flies, and in mice on a high-fat diet. In people it fails to reliably switch on the enzyme it targets, and higher intake tracks no drop in death, cancer or heart disease.
What commercial telomere-length tests can and cannot tell you about ageing
The length of your chromosome caps is a noisy population-level marker, not a personal verdict — and genetically longer telomeres raise the risk of several cancers, not lower it.