What they are
The “hallmarks of aging” are an influential framework that groups the biology of ageing into a set of interconnected processes. The 2023 update lists twelve, including genomic instability, telomere attrition, epigenetic alterations, loss of proteostasis, deregulated nutrient sensing, mitochondrial dysfunction and cellular senescence.
Why the framework matters
Each hallmark should meet three criteria: it appears with age, accelerating it speeds ageing, and reversing it slows ageing. The framework gives longevity research a shared map — most interventions on this site target one or more hallmarks rather than “ageing” in the abstract.
What the evidence shows
The hallmarks are widely accepted as an organising model, but they are descriptive, overlapping and still debated. Showing that a treatment moves a hallmark biomarker (for example an epigenetic clock) is not the same as proving it extends healthy human lifespan.
How we use it
We map treatments to the hallmark(s) they plausibly address and rate the human evidence separately — so a strong mechanism is never mistaken for a proven outcome.