For how we live.
Healthspan, aging biology, and the claims the anti-aging market makes.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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%.
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.
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.
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.