The methods behind CHAI. The research shaping longevity care.
Explore CHAI’s methods, explanations of biological-age estimates and weekly summaries of longevity research.
CHAI white papers
Understand how CHAI calculates its results, handles lab differences and shows uncertainty.
When lab results can be compared
How CHAI handles results from different labs and methods, and determines which results can support a trend.
How CHAI estimates biological age
How the Centurion Clock and PhenoAge contribute to CHAI’s biological-age estimate, its range and the factors behind it.
The science of longevity
What the evidence says about biological age, healthspan and the markers a practice can actually move.
The weekly longevity brief
Weekly summaries of longevity research, with study context, key findings and practical implications.
Longevity science brief · September 18, 2026
Pooled caloric-restriction trials improve a six-marker aging composite with only half the effect explained by weight loss; older adults on self-selected vegan diets lose muscle; a thousand unrecognised brain microproteins.
Longevity science brief · September 11, 2026
Rentosertib moves six proteomic aging clocks in a small human trial; senescent cells hide behind PD-L2; twelve weeks of resistance training improves objective sleep; folate and homocysteine track aging.
Longevity science brief · September 4, 2026
Semaglutide extends lifespan in old female mice; epigenetic clocks predict survival to 90 but not preserved cognition; the muscle caveat for GLP-1 use in older adults.
Longevity science brief · August 28, 2026
A 100,000-person study finds aging is sex-specific and metabolically driven; a candidate geroprotective probiotic; sleep duration and biological age; two mouse immune papers not to act on.
Longevity science brief · August 21, 2026
A Nature Medicine harmonisation of 51 intervention trials shows aging clocks are not interchangeable; rapamycin moves immune markers but not epigenetic age; a 48-month exercise trial preserves cognition.