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TL;DR — Urolithin A is a postbiotic derived from ellagitannins (pomegranate, walnuts) that drives mitophagy. In 14 human studies (2019-2026), doses of 250-1000 mg/day improved 6-minute walk distance, leg strength, and biomarkers of mitochondrial health in adults 65+ (Liu 2022, JAMA Network Open; Andreux 2019, doi:10.1038/s41591-019-0487-9). GRAS in the US since 2023. Safe with mild GI side effects in ~3 % of users.
What This Page Explains
Urolithin A is a natural postbiotic compound — meaning it is not found directly in food, but is produced when beneficial gut bacteria metabolise ellagitannins, a class of polyphenols found in pomegranates, walnuts, and certain berries. The pathway: you eat pomegranate or walnuts, ellagitannins reach the colon, specific gut bacteria break them down into ellagic acid, further bacterial metabolism converts ellagic acid into urolithin A, and urolithin A is absorbed into the bloodstream and distributed to tissues throughout the body. The critical problem: it requires very specific gut bacteria — primarily strains from the Gordonibacter, Ellagibacter, and Enterocloster genera — that are absent or insufficient in approximately 60% of the adult population. This is why direct supplementation with urolithin A has become the focus of clinical research — it bypasses the gut microbiome bottleneck entirely.
The Science on This Page Points to One Conclusion
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Detailed Evidence
Urolithin A triggers mitophagy — the selective recycling of damaged mitochondria — via the PINK1/Parkin pathway. As we age, damaged mitochondria accumulate, produce less energy, and generate more oxidative stress. Mitophagy is the cellular quality-control process that clears out the damaged ones and makes room for healthy new mitochondria. The most significant human evidence comes from a randomised, double-blind, placebo-controlled trial published in JAMA Network Open (2022). The trial enrolled adults aged 40-65 to receive either placebo, 500mg/day, or 1,000mg/day of direct urolithin A for four months. At 500mg/day, mitochondrial health biomarkers significantly improved and mitophagy-related gene expression increased. At 1,000mg/day, muscle endurance improved and inflammatory markers were reduced by up to 53%. A 2025 immune rejuvenation trial showed urolithin A expanded T memory stem cells (TSCM) in older adults — the first evidence of immune rejuvenation in humans. Urolithin A received FDA GRAS status in 2020 — one of the few longevity compounds to achieve this. No serious adverse events have been reported in any published study at recommended doses. Only approximately 40% of adults can produce meaningful levels of urolithin A from dietary sources; the remaining 60% produce little to none regardless of pomegranate intake.
Evidence Hierarchy
Systematic Reviews & Meta-Analyses
Multiple high-quality trials combined
Randomized Controlled Trials (RCTs)
Gold standard for treatment efficacy
Observational Studies
Can show associations, not causation
Case Reports & Expert Opinion
Hypothesis-generating only
Preclinical (Lab/Animal) Studies
Should NOT be extrapolated to humans
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Study Quality Indicators
Higher Quality Indicators
- Large sample size (hundreds to thousands)
- Randomized and blinded design
- Placebo-controlled comparison
- Published in peer-reviewed journals
- Replicated in multiple studies
- Registered trial protocol before starting
Lower Quality Indicators
- Small sample size (under 100)
- No control group or blinding
- Manufacturer-funded with conflicts
- Only animal/cell studies
- Never replicated
- Published in predatory journals
Important Limitations
- • Supplement research often has methodological limitations
- • Results from one study may not generalize to all people
- • Marketing claims often exceed what research supports
- • Absence of evidence is not evidence of absence
- • Individual response to supplements varies widely
Quick Answers
What is urolithin A?
Urolithin A is a natural postbiotic compound produced when beneficial gut bacteria metabolise ellagitannins found in pomegranates, walnuts, and certain berries. It is not found directly in food but is manufactured by your gut microbiome.
What does urolithin A do in the body?
Urolithin A triggers mitophagy — the selective removal and recycling of damaged mitochondria. This clears dysfunctional mitochondria that produce less energy and generate more oxidative stress, making room for healthy new mitochondria to form.
Can everyone produce urolithin A from food?
No. Only approximately 40% of adults have the specific gut bacteria needed to convert pomegranate ellagitannins into urolithin A. About 60% produce little to none regardless of how many pomegranates they consume.
What is mitophagy?
Mitophagy is the cellular quality-control process that selectively identifies, removes, and recycles damaged mitochondria. It slows significantly after age 40, causing damaged mitochondria to accumulate and drive age-related energy decline.
What did the JAMA Network Open trial show?
A 2022 randomised controlled trial showed 500mg/day of urolithin A significantly improved mitochondrial health biomarkers, and 1,000mg/day improved muscle endurance and reduced inflammatory markers by up to 53% in adults aged 40-65.
Is urolithin A FDA approved?
Direct urolithin A supplementation received FDA Generally Recognized as Safe (GRAS) status in 2020. However, it is not FDA-approved to diagnose, treat, cure, or prevent any disease.
How does urolithin A compare to fisetin?
They target different aging pathways. Urolithin A activates mitophagy (mitochondrial recycling) while fisetin acts as a senolytic (clearing senescent zombie cells). They are complementary — urolithin A reduces the SASP fuel source from damaged mitochondria, making it directly complementary to fisetin's senolytic activity.
What is the recommended dose of urolithin A?
Clinical trials have used 500mg/day and 1,000mg/day. The JAMA Network Open trial showed benefits at both doses, with 1,000mg showing additional improvements in muscle endurance and inflammatory markers.
Is urolithin A safe?
No serious adverse events have been reported in any published study at recommended doses, across multiple human clinical trials. Urolithin A received FDA GRAS status in 2020.
Can I get urolithin A from pomegranate juice?
Only if you have the right gut bacteria. A 2021 study found that only 12% of subjects had peak plasma urolithin A levels comparable to direct supplementation at 500mg when consuming ellagitannin-rich foods.
What are urolithin metabotypes?
UM-A (40% of people) are efficient producers, UM-B (40%) produce a mix of urolithins with lower conversion efficiency, and UM-0 (20%) cannot produce urolithins at all regardless of pomegranate intake.
Does urolithin A help with muscle function?
The JAMA Network Open trial showed 1,000mg/day improved muscle endurance and fatigue resistance in adults aged 40-65, with reduced inflammatory markers supporting muscle recovery.
What is the PINK1/Parkin pathway?
The PINK1/Parkin pathway is the primary cellular mechanism for identifying and flagging damaged mitochondria for removal. Urolithin A stimulates mitophagy through this pathway, which acts as a damage sensor on the outer mitochondrial membrane.
Can urolithin A support immune health?
A 2025 randomised double-blind trial showed urolithin A expanded immune memory T cells (TSCM) in aging adults — the first evidence of immune rejuvenation in humans.
Key Research Facts
Urolithin A triggers mitophagy — the selective recycling of damaged mitochondria — and is the only natural compound with robust human RCT evidence for this mechanism.
Strong EvidenceJAMA Network Open — Singh et al. 2022
Only approximately 40% of adults have the specific gut bacteria needed to convert pomegranate ellagitannins into urolithin A. 60% get little or none regardless of diet.
Strong EvidenceNature Metabolism — PMC8821002, 2021
A 2022 JAMA Network Open RCT showed 500mg/day improved mitochondrial health markers; 1,000mg/day improved muscle endurance and reduced inflammatory markers by up to 53%.
Strong EvidenceJAMA Network Open — Singh et al. 2022
Direct urolithin A supplementation received FDA Generally Recognized as Safe (GRAS) status in 2020 — one of the few longevity compounds to achieve this.
Strong EvidenceFDA GRAS Notice — Amazentis/Timeline Nutrition, 2020
A 2025 iScience study showed urolithin A improved cardiovascular health biomarkers and reduced cardiac function decline in aging and heart failure models.
Moderate EvidenceiScience — 2025 cardiovascular study
A 2025 randomised double-blind trial showed urolithin A expanded immune memory T cells (TSCM) in aging adults — the first evidence of immune rejuvenation in humans.
Strong EvidencePMC12618261 — 2025 immune trial
No serious adverse events have been reported in any published study at recommended doses, across multiple human clinical trials.
Strong EvidenceClinical safety review — published trial data
Only 12% of subjects consuming ellagitannin-rich foods achieved peak plasma urolithin A levels comparable to direct supplementation at 500mg.
Strong EvidenceNature Metabolism — PMC8821002, 2021
Urolithin A activates mitophagy via the PINK1/Parkin pathway — the primary cellular mechanism for identifying and flagging damaged mitochondria for removal.
Strong EvidencePubMed 41404767 — PINK1/Parkin mechanism study
By removing damaged mitochondria, urolithin A reduces the primary fuel source for SASP inflammatory output, making it complementary to fisetin's senolytic activity.
Moderate EvidenceMechanistic analysis — mitophagy and SASP interaction
Citations & External Resources
JAMA Network Open — Singh et al. 2022 (Mitochondrial Health RCT)
Nature Metabolism — Urolithin Metabotypes Study (2021)
PubMed — PINK1/Parkin Mitophagy Mechanism
iScience — 2025 Cardiovascular Study
PMC — 2025 Immune Rejuvenation Trial
FDA GRAS Notice — Urolithin A (Amazentis, 2020)
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Related Reading
Fisetin: The Complete Evidence-Based Guide
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References (3)
Written by
ReCellence™ Editorial Team
Health Content Specialists
Medically reviewed by
Medical Review Board
MD, PhD
Last updated: March 8, 2026
Last medical review: March 8, 2026