Published 2026-09-16 · Last reviewed 2026-09-16 · By Andy Palenzuela, Founder
Urolithin A is the rare longevity ingredient with an unusual story: it is not in any food, your body cannot make it on its own, and whether you produce it at all depends on which bacteria happen to live in your gut. This article explains what urolithin A is, how it gets made (or does not), what mitophagy means in plain English, what the two human trials measured at 500 and 1,000 mg, and how to read a urolithin A label. It is written by the founder of Age Revive, who spent 14+ years inside regulated nutrition supply chains before formulating CELLUBIOME around 500 mg of urolithin A.
Urolithin A is a dibenzopyranone — a small, two-ring molecule that belongs to a family of compounds called urolithins. It is a metabolite: something produced by the transformation of another molecule, not a nutrient that exists in the diet as-is.
The chain of custody runs like this:
Steps one and two are reliable. Step three is the bottleneck, and it is why urolithin A exists as a supplement at all.
Research suggests most people's microbiomes do not convert ellagic acid to urolithin A efficiently. The bacteria responsible are not universal, and even among people who carry them, output varies widely. Researchers describe people by urolithin "metabotype" — roughly, those who produce urolithin A, those who produce other urolithins instead, and those who produce essentially none.
The practical consequence is blunt: eating pomegranate does not guarantee urolithin A. Two people can drink the same juice and end up with very different blood levels, and one of them may end up with nothing measurable. A direct urolithin A supplement bypasses step three entirely — it supplies the end product whether or not your bacteria can make it.
Mitochondria are the parts of the cell that turn food-derived fuel into usable energy. They are also disposable. Individual mitochondria wear out, accumulate damage, and become less efficient, and a cell that keeps too many worn-out ones runs worse than a cell that recycles them.
Mitophagy is the recycling program. A damaged mitochondrion is tagged by the cell, wrapped in a membrane, delivered to the cell's digestive compartment, and broken down into components that can be reused. Clearing old mitochondria makes room for the cell to produce fresh ones. The word combines mito (mitochondria) and phagy (eating) — the cell eats its own worn-out parts on purpose.
Urolithin A is studied for its role in supporting mitophagy. In the human research, that support has been measured as changes in mitochondrial biomarkers — gene-expression signatures in muscle tissue and metabolite patterns in blood — rather than as a direct count of recycled mitochondria. "Supports mitochondrial renewal through the mitophagy pathway" is the structure/function description; it is not a claim that the process is switched on like a light.
Published in Nature Metabolism, this was a randomized, double-blind, placebo-controlled trial in 60 sedentary older adults aged 61 to 85. It ran in two phases: a single-dose phase, then a 28-day phase in which participants took 250, 500, or 1,000 mg of urolithin A daily, or placebo.
The primary endpoint was safety and tolerability. Urolithin A was reported as safe and well tolerated at all doses. Secondary and exploratory measures included plasma acylcarnitines, which decreased, and skeletal-muscle gene expression, where the authors reported a mitochondrial gene-expression signature at the 500 mg and 1,000 mg doses. The study did not report improvements in physical performance over the four weeks.
What it established: urolithin A is well tolerated up to 1,000 mg/day for 28 days in this population, and the 500 and 1,000 mg doses were associated with a mitochondrial biomarker signature. What it did not: any functional outcome, and nothing beyond four weeks.
Published in Cell Reports Medicine, this was a randomized, placebo-controlled trial in middle-aged adults who took 500 mg or 1,000 mg of urolithin A daily for four months. The authors reported changes in muscle-strength and exercise-performance measures and in mitochondrial-health biomarkers versus placebo.
What it established: a longer exposure (four months) at the same two doses, with biomarker and performance-measure findings reported at the study level. What it did not: anything about a finished supplement, and its trial averages are not a promise of individual results. Age Revive does not make strength or performance claims for CELLUBIOME on the basis of this study.
Citation hygiene note for readers who look these up: Andreux et al. is the 2019 Nature Metabolism paper. Singh et al. is the 2022 Cell Reports Medicine paper. They are frequently confused online.
| Trial | Dose | Duration | Population | Primary finding |
|---|---|---|---|---|
| Andreux 2019 | 250 / 500 / 1,000 mg/day | 28 days | 60 sedentary adults, 61–85 | Safe and well tolerated; mitochondrial gene-expression signature at 500 and 1,000 mg |
| Singh 2022 | 500 / 1,000 mg/day | 4 months | Middle-aged adults | Changes in muscle-strength, exercise-performance, and mitochondrial-health biomarkers vs placebo |
500 mg is the dose that appears in both trials and the lower of the two that produced a biomarker signature in Andreux 2019. 250 mg was tested in Andreux only and did not produce the same signature.
CELLUBIOME provides 500 mg of urolithin A per daily serving (2 enteric-coated capsules), at ≥99% purity. The current lot certificate, published on our quality page, shows urolithin A tested at 548.15 mg per serving against a label claim of not less than 500 mg. The dose is aligned with the published human research. It is not "dose-matched" — the trials tested the compound alone, not CELLUBIOME, and not alongside tributyrin.
Urolithin A is a gut-derived molecule that works downstream, in the mitochondria. Left on its own in a formula, it says nothing about the gut it came from — specifically the colon lining, whose cells run on a short-chain fatty acid called butyrate. CELLUBIOME pairs 500 mg urolithin A with 500 mg tributyrin (a butyrate triglyceride designed to survive stomach acid) so that one serving supports both the gut barrier and mitochondrial renewal. Not just gut. Mitochondria too. The reasoning is covered in Urolithin A + Tributyrin: Gut Barrier and Mitochondrial Support, and the delivery choice in Tributyrin vs Sodium Butyrate.
In the human trials above, urolithin A was well tolerated at up to 1,000 mg/day over 28 days (Andreux 2019) and at 500 and 1,000 mg/day over four months (Singh 2022). Those are study populations of healthy adults; they are not a clearance for everyone. If you are pregnant, breastfeeding, managing a condition, or taking medication, speak with your clinician before starting any supplement.
What does urolithin A do? Urolithin A is studied for its role in supporting mitophagy — the process by which cells recycle worn-out mitochondria. In human trials at 500–1,000 mg/day it was well tolerated and associated with changes in mitochondrial biomarkers. It is a gut-derived metabolite, not a probiotic.
Can I get urolithin A from pomegranate? Only if your gut bacteria convert it. Pomegranate contains ellagitannins, the raw material; specific bacteria turn them into urolithin A, and research suggests most people's microbiomes do not do this efficiently. Supplemental urolithin A supplies the end product directly.
What is the right urolithin A dose? Human trials used 250, 500, and 1,000 mg per day. The 500 mg and 1,000 mg doses were associated with mitochondrial biomarker changes; 250 mg was not, in the one trial that tested it. CELLUBIOME provides 500 mg per daily serving. Dose decisions belong with your clinician.
Is urolithin A safe to take every day? In published human trials, daily urolithin A at up to 1,000 mg was well tolerated over 28 days and, at 500–1,000 mg, over four months. Those trials were in healthy adults; consult your clinician if you are pregnant, managing a condition, or on medication.
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Andy Palenzuela is the founder of Age Revive and has 14+ years of experience in regulated nutrition supply chains, including manufacturing oversight, ingredient sourcing, and quality assurance for consumer health products. Age Revive formulas are developed based on published peer-reviewed research and manufactured at cGMP-certified facilities. LinkedIn
These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease. The information in this article is for educational purposes only and is not intended as medical advice. Consult your healthcare provider before starting any supplement regimen.