CRISPR-Cas9 is a molecular tool that allows scientists to cut DNA at precise locations and either disable a gene or insert a new sequence. Since its development as a gene-editing technology in 2012, it has moved with extraordinary speed from laboratory curiosity to clinical application. The first CRISPR-based therapy was approved by the FDA in late 2023 for sickle cell disease — a rare inherited blood disorder. That approval was significant not just for the patients it helped but as proof of concept that CRISPR therapies can be safe and effective in humans.

For longevity specifically, the targets are more complex. Single-gene disorders like sickle cell are straightforward compared to the polygenic, multi-mechanism biology of ageing. But several directions are actively being explored. FOXO3 is a gene with strong associations with longevity across multiple human populations — certain variants appear in centenarians at higher rates. Genes involved in DNA repair, inflammation regulation, and telomere maintenance are all targets of active research. The challenge is that enhancing longevity-related gene function in a living organism is orders of magnitude more difficult than correcting a single mutation.

The near-term clinical applications of CRISPR in ageing are most likely to come through specific age-related diseases — Alzheimer's, cardiovascular disease, age-related macular degeneration — rather than through direct anti-ageing interventions. But each successful application builds the safety and delivery infrastructure that more ambitious programmes will eventually need.