People who live past 100 share a distinct blood chemistry "fingerprint," study finds

Genetics are estimated to account for as much as half of the ability to reach extreme old age, with lifestyle factors like diet, movement and social connection filling in much of the rest. What has remained less clear is whether centenarians also carry a distinct metabolic signature — and a 2026 Boston University study set out to find one in their blood chemistry.

What the researchers measured

The team analyzed blood samples from 213 participants in the New England Centenarian Study, one of the largest investigations of exceptionally long-lived people in North America, including 70 centenarians, their children, and age-matched controls. Using an untargeted metabolomics assay, they measured roughly 1,495 small molecules in blood serum, comparing levels across the three groups and cross-checking results against four additional independent metabolomics datasets to confirm which signals held up consistently.

The centenarian "fingerprint"

Centenarians showed unusually high levels of certain primary and secondary bile acids, along with preserved levels of several steroids — a pattern that differed from what’s typically seen in ordinary aging and was independently associated with a lower risk of death in survival analysis. The researchers also built a machine-learning "metabolomic clock" that estimated biological age from these metabolite levels, finding that being biologically younger than one’s chronological age by this measure was itself linked to better survival.

"Our study points to measurable chemical fingerprints in the blood that are associated with living a very long and healthy life." — Stefano Monti, PhD, corresponding author, Boston University

Why bile acids specifically are interesting

Bile acids are produced by the liver and modified by gut bacteria — meaning this signature sits at the intersection of liver function, metabolic health and the gut microbiome, three areas that show up repeatedly across separate aging research. The researchers flag several biological pathways worth further study as a result, including bile acid metabolism, NAD-related pathways, gut bacterial metabolites, oxidative stress markers and specific steroids.

What this doesn’t yet mean

This is a cross-sectional study, meaning the researchers can’t yet say whether this blood signature causes exceptional longevity or is simply a downstream marker of it — and the authors are explicit that the findings need validation in larger, more diverse populations before they could inform any test or intervention. The near-term value is as a biomarker candidate for estimating biological age and identifying who might be aging unusually well (or unusually fast), not as a therapy target yet.

The practical takeaway

While a validated "centenarian blood test" isn’t available yet, the pathways implicated — liver and bile acid metabolism, gut bacterial health, oxidative stress — are all indirectly supported by the same levers already well established in the longevity literature: fibre intake, limiting excess alcohol and ultra-processed food, and maintaining muscle mass and metabolic health generally.

This is exactly the kind of exploratory biomarker research Misi’s Longevity Lab keeps an eye on — not to chase every new metabolite before it’s validated, but to make sure the foundational levers (liver health, gut health, metabolic markers) already in your bloodwork stay on track while the research matures.