○ Evidence tier 4 — Human RCT — biomarker endpoint

Record verify: primary source pending

DesignRandomized, placebo-controlled trial (biomarker)
DOI10.1038/s43587-025-00996-x
Citation statusdoi verified via Crossref 2026-07-12 (Nature Aging 2025;5:2309-2322, 'Effect of the mitophagy inducer urolithin A on age-related immune decline: a randomized, placebo-controlled trial'). PMID + NCT: needs_primary_fulltext.

Five-qualifier claim

Species / populationOlder adults with age-related immune decline (randomized, placebo-controlled trial).
Exposure, route, scheduleOral urolithin A for several months.
Comparator / durationPlacebo-controlled, randomized.
Endpoint / numeric resultReported improvements in immune-cell/mitochondrial biomarkers associated with aging immune function.
What it did NOT establishImmune-biomarker endpoints — not a functional disability, disease-outcome, or lifespan endpoint, and not a healthy-aging-longevity result.

Primary reference

https://doi.org/10.1038/s43587-025-00996-x

Exact identifier confirmed against the primary record via Crossref/ClinicalTrials.gov where stated in the citation status; anything marked needs_primary_fulltext is not yet confirmed.