Urolithin A: The Complete Guide

What You Need to Know

• Urolithin A is not in any food. Gut bacteria make it from the ellagitannins in pomegranate, walnuts, and berries, and in a 100-person study only about 40% of adults converted a glass of pomegranate juice into a meaningful amount (Singh 2021, European Journal of Clinical Nutrition).
• In the largest trial to date, 500 mg a day for four months raised hamstring strength about 12% in 88 sedentary adults aged 40 to 64, while the placebo group lost about 10% (Singh 2022, Cell Reports Medicine).
• Doubling to 1,000 mg did not add strength (9.8% vs 12%). It produced within-group gains in peak oxygen uptake (about 10%) and six-minute walk distance (33 meters) that 500 mg did not, but neither beat placebo.
• Muscle endurance separated from placebo at two months in adults aged 65 to 90 taking 1,000 mg (Liu 2022, JAMA Network Open); strength and aerobic changes were measured at four months. Nothing is felt in week one.
• Safety: an FDA GRAS notice closed with no questions in 2018 (GRN 791), a rat no-effect level above 3,400 mg per kg per day, and adverse events equal to placebo in trials up to four months. There is no human data beyond four months and none in pregnancy.
• Mitopure and generic urolithin A are the same synthetic molecule, 3,8-dihydroxy-urolithin. The real differences are the brand's trial pedigree, its NSF Certified for Sport mark, and about $3.30 a day versus $1.50 for a lot-tested generic.
• Urolithin A is not a stimulant. It has no caffeine, does not act on the nervous system, and no trial has measured alertness; the outcomes were strength and endurance over months.
• No study has measured lifespan in humans. The only lifespan data is in roundworms (Ryu 2016, Nature Medicine); in mice and rats the outcomes were running capacity and grip, not longevity.

What is urolithin A, and why does it matter?

Urolithin A is a small molecule (chemists call it 3,8-dihydroxy-urolithin) that certain gut bacteria make when you eat foods rich in ellagitannins, a family of plant tannins found in pomegranate, walnuts, raspberries, and strawberries. You do not eat urolithin A. It is not in any food. Your microbiome either builds it for you or it does not, and for a large share of adults it does not.

The reason anyone cares is mitophagy. Every cell runs on mitochondria, the organelles that turn food and oxygen into usable energy. Mitochondria wear out, and worn mitochondria leak, misfire, and make less energy per unit of fuel. Mitophagy is the cell's recycling program for them: it tags a damaged mitochondrion, wraps it, dismantles it, and reuses the parts. The program slows with age, right when the damaged units pile up. That mismatch is one of the better-supported explanations for why muscle gets weaker and tires faster past 50.

In 2016, a team at EPFL in Lausanne reported in Nature Medicine that urolithin A switched mitophagy on in cells, in roundworms, and in rodents. The worms lived longer. Old mice ran farther (Ryu et al., 2016, Nature Medicine). That paper is the origin of the entire category, and everything since has been an attempt to show the same thing in people.

The human mechanism data arrived six years later. In muscle biopsies from a four-month trial in middle-aged adults, 500 mg a day raised the proteins of the PINK1/Parkin pathway (the molecular tagging system that marks a mitochondrion for recycling) and increased the active, phosphorylated form of Parkin itself. Proteins of the electron transport chain, the machinery that makes ATP, rose in a dose-dependent way (Singh et al., 2022, Cell Reports Medicine). That is about as direct as mechanism evidence gets without opening someone up.

Why muscle? It is dense with mitochondria and easy to biopsy, so every human trial has looked there first. The same machinery exists in the heart, brain, liver, and immune cells, which is why newer studies are branching out.

Go deeper: how the PINK1/Parkin mitophagy pathway works, step by step, and the Urolithin A monograph for every form on the market and the complete evidence table.

Why can't most people make urolithin A from pomegranate?

Because the conversion depends on specific bacteria that many adults do not carry in useful numbers. The pathway runs ellagitannins to ellagic acid to a chain of intermediate urolithins and finally to urolithin A, and each step needs an enzyme that only a few gut species produce. The first one identified, Gordonibacter urolithinfaciens, was isolated from a healthy human stool sample in 2014 (Selma et al., 2014, International Journal of Systematic and Evolutionary Microbiology). A second genus that finishes the job differently, producing isourolithin A instead, was described in 2017 (Selma et al., 2017, Frontiers in Microbiology).

Researchers sort people into three "metabotypes" by what shows up in their urine after a pomegranate meal. Metabotype A makes urolithin A. Metabotype B makes urolithin A plus isourolithin A and urolithin B. Metabotype 0 makes none. Across trials with walnuts, berries, and pomegranate, metabotype A has ranged from 25% to 80% of volunteers, B from 10% to 50%, and 0 from 5% to 25%, and the split did not depend on which food was eaten or how much (Tomás-Barberán et al., 2014, Journal of Agricultural and Food Chemistry).

Those are wide ranges. The most useful single number comes from a study built to answer the question directly: 100 healthy adults got a glass of pomegranate juice or a 500 mg urolithin A food product. Only 12% had any urolithin A in their blood at baseline. After the juice, about 40% converted the precursors into a meaningful amount. The rest did not. Producers had higher gut microbiome diversity and a higher ratio of Firmicutes to Bacteroidetes, two broad bacterial groups. Direct supplementation produced more than six times the urolithin A exposure of the juice (Singh et al., 2021, European Journal of Clinical Nutrition).

Age is the biggest known predictor. In a Spanish cohort of 839 people aged 5 to 90, age was the dominant factor determining a person's urolithin metabotype (Cortés-Martín et al., 2018, Food & Function). Nobody has shown a reliable way to turn a non-producer into a producer with diet alone.

Go deeper: the Urolithin A monograph walks through the full gut conversion pathway with a diagram, and explains why the same handful of walnuts gives two people wildly different blood levels.

How do you know whether you make it?

You cannot find out at the pharmacy. There is no consumer test, no panel your clinician can order, and no symptom that tells you your metabotype. Unlike vitamin D, where a blood test gives you a number and a target range (our vitamin D guide explains the test), producer status has only been measured in research settings, by giving someone pomegranate and tracking urolithin A and its conjugates (the glucuronide and sulfate forms the liver attaches for excretion) in blood or urine over the next day (Singh et al., 2021).

The research gives you base rates instead. About 12% of healthy adults had detectable urolithin A at baseline in the 100-person study; in the 88-person middle-aged trial, roughly 15% did (Singh et al., 2022). Before any intervention, something like one adult in seven has measurable urolithin A. The rest do not.

What to watch instead: nothing, honestly. Urolithin A is not something you feel. The trial outcomes were strength on a dynamometer, contractions to fatigue, and oxygen uptake on a bike, at two and four months. You take this on the strength of the trials or not at all.

Go deeper: the trial data as charts, including the blood biomarkers (acylcarnitines, C-reactive protein) the researchers tracked.

Can food and lifestyle get you there?

For a minority of people, partly. For most, no. If you are a strong metabotype A producer, a daily serving of pomegranate, a handful of walnuts, or a cup of raspberries will give you some urolithin A. Even then, the quantity is a fraction of a supplemental dose: the 500 mg product delivered more than six times the exposure of a glass of pomegranate juice (Singh et al., 2021). If you are metabotype 0, the food does nothing on this axis. It is still fruit. Eat it anyway.

Exercise is the other lever, and it is a real one. Training activates mitophagy and mitochondrial biogenesis on its own, which is the comparison the researchers themselves draw: the mitochondrial protein increases after four months of supplementation were, in their words, comparable to what is seen after exercise regimens (Singh et al., 2022). Urolithin A reproduced part of what training does, in people who were not training. It did not add to training in the one study that tested athletes (next section).

Gut diversity tracks with producer status, but no trial has shown that improving diversity flips a non-producer. The bacteria involved are obligate anaerobes that are hard to culture and are not sold as probiotics. The 2017 microbiology paper floated them as "potential novel probiotics" and noted the safety and efficacy work had not been done (Selma et al., 2017). It still has not.

Go deeper: which urolithin A supplements are worth buying opens with the most common mistake in this category: buying a pomegranate extract labeled as if it were urolithin A.

What did the human trials actually measure and find?

Six randomized, placebo-controlled trials in humans, every one four weeks to four months long, every one co-authored by scientists from Amazentis, the company that makes Mitopure. That is normal for a patented ingredient and does not make the data wrong; it does mean no independent group has replicated it yet. Here is the full set.

Safety and biomarkers first (2019). Sedentary older adults took single doses, then four weeks of 250, 500, or 1,000 mg a day. Safety was the primary outcome and it was clean. At 500 and 1,000 mg, four weeks shifted plasma acylcarnitines (fatty-acid fragments that build up when mitochondria process fat inefficiently) and turned up mitochondrial gene expression in muscle biopsies (Andreux et al., 2019, Nature Metabolism). No strength or endurance was measured.

Older adults (2022). Sixty-six adults aged 65 to 90 (mean 71.7, three-quarters women) took 1,000 mg or placebo for four months. The primary endpoints, six-minute walk distance and peak ATP production in a hand muscle, did not separate from placebo; the walk improved 60.8 meters on urolithin A and 42.5 on placebo. Muscle endurance did separate. At two months the hand muscle managed 95 more contractions to fatigue on urolithin A versus 12 on placebo, and the shin muscle 41 versus 6. Acylcarnitines, ceramides, and C-reactive protein (CRP, a general blood marker of inflammation) all fell (Liu et al., 2022, JAMA Network Open). Limitation: every participant was white, the group was small, and the primary endpoints missed.

Middle-aged adults (2022). This is the trial everyone quotes. Eighty-eight sedentary, overweight adults aged 40 to 64 took 500 mg, 1,000 mg, or placebo for four months. Hamstring strength rose 12% at 500 mg and 9.8% at 1,000 mg against placebo, while the placebo group lost about 10%. Peak power output, the pre-registered primary endpoint, did not reach significance at either dose (both rose about 4%). The 1,000 mg group improved its own peak oxygen uptake by roughly 10% and walked 33 meters farther in six minutes, but neither beat placebo at the conventional threshold (p = 0.058 and p = 0.098). CRP fell at both doses (Singh et al., 2022). Limitation: the primary endpoint missed, and the trial was powered as a proof of concept.

Immune cells (2025). Fifty healthy middle-aged adults took 1,000 mg or placebo for four weeks. Urolithin A expanded naive-like, less-exhausted CD8 T cells by half a percentage point and raised their capacity to burn fatty acids by about 15 percentage points (Denk et al., 2025, Nature Aging). These are cell-composition changes, not infection outcomes. The mouse work behind it showed urolithin A expanding T memory stem cells through PINK1-driven mitophagy in tumor-bearing animals (Denk et al., 2022, Immunity). Our immune health guide covers what is established for immune function more broadly.

Trained athletes (2025). Forty-two competitive male distance runners, average age 27, took 1,000 mg or placebo for four weeks at an altitude camp. The 3,000 m time trial did not improve. Perceived exertion and creatine kinase (a muscle-damage marker) after the time trial were lower. VO2max rose 5.4% on urolithin A and 3.6% on placebo, not a significant difference (Whitfield et al., 2025, Sports Medicine). Read this one before taking it in your twenties.

Skin, applied topically (2026). A cream reduced periorbital wrinkle depth after eight weeks and blunted UVB-induced redness (D'Amico et al., 2026, iScience). It is a cosmetic result from a cream and says nothing about what a capsule does to your face.

Evidence grades by outcome. Muscle strength in sedentary adults 40 to 64: Moderate (one well-run RCT, two doses, consistent direction, primary endpoint missed). Muscle endurance in adults 65 to 90: Moderate (one RCT, secondary endpoint, large effect). Aerobic capacity: Preliminary (within-group gains only). Blood markers of mitochondrial efficiency and inflammation: Preliminary (consistent across three trials, no clinical outcome attached). Immune cell composition: Preliminary (one four-week RCT). Performance in trained young athletes: Insufficient, and the one trial was negative. Lifespan: Insufficient, because there is no human data at all. The only lifespan measurement in the literature is in roundworms (Ryu et al., 2016); the mouse and rat work measured running and grip, not how long the animals lived.

In the animal pipeline. Urolithin A restored mitophagy and improved muscle function and survival in mouse models of Duchenne muscular dystrophy (Luan et al., 2021, Science Translational Medicine). In a human microglial cell line, urolithin A and nicotinamide riboside both reduced DNA-damage-induced senescence but steered inflammatory signaling in different directions (Madsen et al., 2024, Frontiers in Aging Neuroscience). A 2021 review catalogs the rest across muscle, brain, joints, and gut (D'Amico et al., 2021, Trends in Molecular Medicine). Animal and cell results are why trials get funded. They are not a reason to buy anything.

Go deeper: the trial data as charts plots every outcome above against placebo so you can see the effect sizes rather than read about them.

What dose did the trials use, and does 1,000 mg beat 500 mg?

The trials used 500 mg and 1,000 mg a day, and for the outcome with the best evidence, 1,000 mg did not beat 500 mg. Hamstring strength rose 12% at 500 mg and 9.8% at 1,000 mg; the two doses were statistically indistinguishable from each other and both separated from placebo (Singh et al., 2022). For strength, the curve is flat between them.

Each dose did something the other did not. At 1,000 mg, within-group peak oxygen uptake and six-minute walk distance improved while the 500 mg group's did not, though neither beat placebo. At 500 mg, plasma acylcarnitines fell and the muscle transcriptome lit up mitochondrial gene sets, while at 1,000 mg neither happened. The authors read this as a dose-and-duration interaction rather than "more is better." Electron transport chain proteins were the one thing that rose dose-dependently.

The older-adult endurance trial used only 1,000 mg, so there is no 500 mg comparison for people over 65 (Liu et al., 2022). Over 65 with endurance as the target, the dose with direct evidence is 1,000 mg. For strength at 40 to 64, 500 mg has the same evidence as 1,000 mg at half the cost.

Timing and form. The trials dosed in the morning, before breakfast, with water, as softgels (Singh et al., 2022). No trial has compared morning to evening or fed to fasted, so "morning, empty stomach" is what was studied, not what was proven superior. Capsules and softgels have not been compared; the molecule is the same.

Time to effect. Biomarkers moved at four weeks (Andreux et al., 2019). Muscle endurance separated from placebo at two months (Liu et al., 2022). Strength and aerobic measures were assessed at four months, a window chosen because muscle takes that long to remodel (Singh et al., 2022). Anyone promising you will feel something in a week is not describing this compound.

The decision rule. Supplementing makes sense if you are over 40, not training hard, and your goal is lower-body strength or endurance; that is who the evidence is for. It makes less sense under 40 and active, because the one trial in that group did not improve performance. It makes no sense as a substitute for exercise, which produced the same mitochondrial changes for free. Stacking is unstudied. People pair it with NAD+ precursors (how NMN raises NAD+) and with CoQ10 on the theory that one clears old mitochondria while the others feed the new ones. Reasonable theory, zero human trials, and the middle-aged trial excluded CoQ10 and vitamin B3 precursors so it could isolate urolithin A.

Go deeper: where the dose-response curve flattens plots the 500 versus 1,000 mg data and explains why the strength curve plateaus.

Who should think twice?

Adults under 40. The only trial in this group, in 27-year-old trained runners, found no performance gain and a lower perceived effort (Whitfield et al., 2025). Mitophagy has not declined much in a healthy, active 30-year-old, so there is less to restore. A sedentary 35-year-old sits in a gap the trials have not covered.

Adults over 65. This is the group with the endurance data (Liu et al., 2022) and the first-in-human safety data (Andreux et al., 2019), and the group where lower-body strength predicts whether you can get off the floor at 80. The trial dose was 1,000 mg. Our overview of supplements for active aging puts urolithin A next to the rest of the category.

Pregnancy and breastfeeding. No data. None of the six trials enrolled pregnant or nursing participants, and the published rat toxicology covered genotoxicity and 28- and 90-day feeding, not reproduction (Heilman et al., 2017, Food and Chemical Toxicology). No data in pregnancy means do not take it in pregnancy.

People on medications. The middle-aged trial excluded anyone on statins, blood thinners, steroids, or thyroid medication (Singh et al., 2022), so there is no interaction data for the drugs most 55-year-olds take. No interaction has been reported, which is different from one having been ruled out. Urolithin A is cleared as glucuronide and sulfate conjugates, the same liver pathways many drugs use. Daily prescription, ask the prescriber first.

Children and teenagers. No data, no reason, and the GRAS notice covers adult food uses.

Anyone with a diagnosed condition. The trials enrolled healthy volunteers. A muscle, heart, liver, kidney, or immune condition makes this a conversation with your clinician, not a page on the internet.

Go deeper: the Urolithin A monograph has the full safety and interactions section, including what to tell your clinician.

What goes wrong? Safety, side effects, and the long-term question

Short term, very little. The toxicology is unusually thorough for a supplement ingredient because it was done for a GRAS filing. In rats, urolithin A was not genotoxic in a full battery of assays, and 90 days at 5% of the diet, equivalent to 3,451 mg per kilogram of body weight per day in males and 3,826 in females, produced no toxic findings and no target organ. That was the highest dose tested (Heilman et al., 2017). For a 75 kg adult, it works out to more than 250 grams a day. The human dose is half a gram.

On that file, Amazentis submitted GRAS notice GRN 791 to the FDA in June 2018 for urolithin A in foods at 250 to 500 mg per serving, up to 1,000 mg. The FDA's letter of December 20, 2018 says it has no questions (FDA GRAS Notice Inventory, GRN 791). "No questions" means the FDA did not dispute the company's safety conclusion. It is not an endorsement of benefit.

In the trials, adverse events tracked placebo: 42 events in the placebo group, 24 at 500 mg, and 36 at 1,000 mg in the middle-aged study, most of the musculoskeletal ones from the biopsy needle rather than the capsule, with no change in blood chemistry, hematology, or urinalysis (Singh et al., 2022). The older-adult trial found no difference in adverse events (Liu et al., 2022), and the first-in-human study's primary outcome was safety (Andreux et al., 2019).

Now the long-term question, plainly: the longest human exposure in any published trial is four months. There is no one-year data, no five-year data, and no human data on whether running mitophagy at a higher rate for a decade has a cost. Mitophagy is a normal process that urolithin A nudges upward, which is reassuring on first principles, but first principles are not data. If you take it for years, you are ahead of the evidence. That is a legitimate choice as long as you know you are making it.

What would worry us: a product that is not actually urolithin A (next section), a dose far above 1,000 mg (no human has been studied there), or taking it instead of seeing a clinician about weakness that has another cause. Weakness that arrives over weeks rather than years is not an aging story. Get it looked at.

Go deeper: the Urolithin A monograph keeps the interaction table and the "ask first" list current as new data comes in.

Mitopure vs generic urolithin A: what is the real difference?

Same molecule, different paperwork, different price. Mitopure is Amazentis's branded urolithin A, sold by its consumer arm Timeline, and Amazentis scientists co-authored every human trial above, so the trial pedigree belongs to their material. Generic urolithin A from other suppliers is the same 3,8-dihydroxy-urolithin, made by chemical synthesis just as Mitopure is; the rat toxicology was explicitly done on synthetic urolithin A (Heilman et al., 2017). There is no "natural" urolithin A in a capsule from anyone. It all comes out of a reactor.

What Mitopure has that generics do not, verified on Timeline's product page on October 13, 2026: the trial pedigree, NSF Certified for Sport status (relevant if you are drug-tested), and a GRAS notice in their name. Mitopure softgels cost $99 for 60, with two a day delivering 500 mg, so about $3.30 a day. The buying guide ranks it first for anyone who wants the exact studied form with a sport certification, and that is the right call for that buyer.

What generics offer: the same 500 mg at a lower price, if, and only if, the product is actually urolithin A at the labeled dose. That is the entire risk, and it has two failure modes. The first is pomegranate extract or ellagic acid sold with "urolithin A" on the front panel, which gives you precursors your gut may not convert (the 40% problem from above). The second is a product that lists urolithin A and is underdosed or adulterated, which you cannot detect without a lab. When we tested 44 supplements bought on Amazon, label and bottle disagreed often enough that we no longer assume they match (what we found when we tested 44 Amazon supplements).

The fix is boring. Buy from a manufacturer that publishes a certificate of analysis for the specific lot you are holding, showing an identity test (is it urolithin A), a potency assay (how many milligrams), and contaminant screens. How to read a supplement certificate of analysis walks through one line by line. A brand that will not show you a lot-specific COA for a $90 bottle is telling you something.

Go deeper: which urolithin A supplements are worth buying in 2026 ranks the US options on dose, testing, transparency, and cost per day, and names the ones that are precursors in disguise.

Where Mt. Angel Vitamins fits

We make one urolithin A product and it is built to match the trials: Urolithin A 500 mg, 60 capsules, one capsule a day, no blend, no pomegranate filler. At $89.99 for a 60-day supply, that is $1.50 a day at the 500 mg dose, verified on our Shopify page on October 13, 2026. It is formulated to support mitochondrial renewal and to help maintain muscle strength and endurance as part of healthy aging.*

The proof stack, stated once: it is made in our own cGMP facility in Mt. Angel, Oregon; every batch is tested in our in-house lab for identity, potency, and purity; and the certificate of analysis for each lot is published at our lab testing page, where you can pull the COA for the lot number on your bottle.

Honest fit: if your priority is the exact branded material from the trials with an NSF Certified for Sport mark, Timeline's Mitopure is the better choice for you, and we say so in the buying guide. If your priority is the studied 500 mg dose, verified by lot, at the lowest honest cost per day, that is what ours is for.

*This statement has not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.

Go deeper: the buying guide puts our product next to Mitopure and three others on the same table.

The bottom line

If you are over 40, not training regularly, and you want to hold onto lower-body strength and endurance, 500 mg of urolithin A a day for at least four months is a reasonable bet with one good trial behind it, and 1,000 mg is the dose with evidence for endurance past 65. If you are under 40 and active, skip it; the one trial in that group came back negative on performance. Buy only a product with a lot-specific certificate of analysis, because the category's real risk is getting pomegranate extract in a urolithin A costume. And do not expect to feel it. Expect to measure it, if at all, in what your legs can do in the spring that they could not do in the fall.

Keep reading

• The Urolithin A monograph: the full mechanism, every form on the market, the complete evidence table, and the interaction list.
• Best Urolithin A supplements, 2026 buyer's guide: five US products ranked on dose, testing, and cost per day, including the precursors in disguise.
• Mitochondrial quality control and urolithin A: the PINK1/Parkin pathway, the biosynthesis bottleneck, and the pharmacokinetics in depth.
• Urolithin A dosage and the plateau effect: why 500 and 1,000 mg produced the same strength gain, with the dose-response data plotted.
• Urolithin A clinical data, visualized: every trial outcome above as a chart against placebo.
• Lab testing and certificates of analysis: the COA for every Mt. Angel Vitamins lot, including Urolithin A 500 mg.
• NMN monograph and the NMN and NR buying guide: the other half of the mitochondrial stack people ask about.

Sources

1. Ryu D, et al. Urolithin A induces mitophagy and prolongs lifespan in C. elegans and increases muscle function in rodents. Nature Medicine. 2016. https://pubmed.ncbi.nlm.nih.gov/27400265/
2. Heilman J, et al. Safety assessment of Urolithin A, a metabolite produced by the human gut microbiota upon dietary intake of plant derived ellagitannins and ellagic acid. Food and Chemical Toxicology. 2017. https://pubmed.ncbi.nlm.nih.gov/28757461/
3. Andreux PA, et al. The mitophagy activator urolithin A is safe and induces a molecular signature of improved mitochondrial and cellular health in humans. Nature Metabolism. 2019. https://pubmed.ncbi.nlm.nih.gov/32694802/
4. Singh A, et al. Direct supplementation with Urolithin A overcomes limitations of dietary exposure and gut microbiome variability in healthy adults to achieve consistent levels across the population. European Journal of Clinical Nutrition. 2021. https://pubmed.ncbi.nlm.nih.gov/34117375/
5. Liu S, et al. Effect of Urolithin A Supplementation on Muscle Endurance and Mitochondrial Health in Older Adults: A Randomized Clinical Trial. JAMA Network Open. 2022. https://pubmed.ncbi.nlm.nih.gov/35050355/
6. Singh A, et al. Urolithin A improves muscle strength, exercise performance, and biomarkers of mitochondrial health in a randomized trial in middle-aged adults. Cell Reports Medicine. 2022. https://pubmed.ncbi.nlm.nih.gov/35584623/
7. Denk D, et al. Effect of the mitophagy inducer urolithin A on age-related immune decline: a randomized, placebo-controlled trial. Nature Aging. 2025. https://pubmed.ncbi.nlm.nih.gov/41174221/
8. Whitfield J, et al. Evaluating the Impact of Urolithin A Supplementation on Running Performance, Recovery, and Mitochondrial Biomarkers in Highly Trained Male Distance Runners. Sports Medicine. 2025. https://pubmed.ncbi.nlm.nih.gov/40839339/
9. D'Amico D, et al. Topical application of urolithin A activates mitophagy and enhances mitochondrial function to promote skin longevity. iScience. 2026. https://pubmed.ncbi.nlm.nih.gov/42866687/
10. Tomás-Barberán FA, et al. Ellagic acid metabolism by human gut microbiota: consistent observation of three urolithin phenotypes in intervention trials, independent of food source, age, and health status. Journal of Agricultural and Food Chemistry. 2014. https://pubmed.ncbi.nlm.nih.gov/24976365/
11. Selma MV, et al. Gordonibacter urolithinfaciens sp. nov., a urolithin-producing bacterium isolated from the human gut. International Journal of Systematic and Evolutionary Microbiology. 2014. https://pubmed.ncbi.nlm.nih.gov/24744017/
12. Selma MV, et al. Isolation of Human Intestinal Bacteria Capable of Producing the Bioactive Metabolite Isourolithin A from Ellagic Acid. Frontiers in Microbiology. 2017. https://pubmed.ncbi.nlm.nih.gov/28824607/
13. Cortés-Martín A, et al. The gut microbiota urolithin metabotypes revisited: the human metabolism of ellagic acid is mainly determined by aging. Food & Function. 2018. https://pubmed.ncbi.nlm.nih.gov/30004553/
14. D'Amico D, et al. Impact of the Natural Compound Urolithin A on Health, Disease, and Aging. Trends in Molecular Medicine. 2021. https://pubmed.ncbi.nlm.nih.gov/34030963/
15. Luan P, et al. Urolithin A improves muscle function by inducing mitophagy in muscular dystrophy. Science Translational Medicine. 2021. https://pubmed.ncbi.nlm.nih.gov/33827972/
16. Denk D, et al. Expansion of T memory stem cells with superior anti-tumor immunity by Urolithin A-induced mitophagy. Immunity. 2022. https://pubmed.ncbi.nlm.nih.gov/36351375/
17. Madsen HB, et al. Urolithin A and nicotinamide riboside differentially regulate innate immune defenses and metabolism in human microglial cells. Frontiers in Aging Neuroscience. 2024. https://pubmed.ncbi.nlm.nih.gov/39665042/
18. U.S. Food and Drug Administration. GRAS Notice Inventory, GRN No. 791, Urolithin A (Amazentis SA). Filed June 15, 2018; closed December 20, 2018. https://www.hfpappexternal.fda.gov/scripts/fdcc/index.cfm?set=GRASNotices&id=791

Common Myths

"I drink pomegranate juice, so I'm covered."

Probably not, and you have no way to check. In the one study that gave 100 healthy adults a glass of pomegranate juice and then measured their blood, only about 40% converted the juice into a meaningful amount of urolithin A, and only 12% had any detectable urolithin A before the test (Singh et al., 2021, European Journal of Clinical Nutrition). The ones who did convert still got less than one-sixth the exposure of a 500 mg capsule. Pomegranate is a fine fruit. It is just not a urolithin A delivery system for most of the people drinking it for that reason.

"Urolithin A is a stimulant. It gives you energy."

It is not and it does not, at least not in any way you will notice by lunch. There is no caffeine in it, it does not act on the nervous system, and no trial has ever measured alertness or subjective energy as an outcome. What the trials measured was leg strength on a dynamometer after four months and muscle contractions to fatigue after two (Singh et al., 2022, Cell Reports Medicine; Liu et al., 2022, JAMA Network Open). The "cellular energy" phrase on every label, including ours, refers to mitochondrial efficiency measured in biopsies and blood, not to how you feel at 3 p.m. If a urolithin A product makes you feel wired, read the rest of the ingredient list.

"It's a longevity supplement. It extends lifespan."

The lifespan data is in worms. In the 2016 Nature Medicine paper, urolithin A extended the lifespan of C. elegans, a roundworm about a millimeter long (Ryu et al., 2016). In mice and rats, the same paper measured running capacity and grip, not how long the animals lived. No human study has measured lifespan, and none is running; the longest human trial is four months. "Longevity" on a urolithin A label is a category name, not a finding. What has been shown in people is a strength and endurance effect in sedentary adults over 40. That is useful. It is not the same thing.

"If 500 mg is good, 1,000 mg is twice as good."

For strength, the two doses did the same thing. In the 88-person middle-aged trial, hamstring strength rose 12% at 500 mg and 9.8% at 1,000 mg, with no statistical difference between them (Singh et al., 2022). The 1,000 mg dose showed within-group gains in aerobic capacity and walk distance that 500 mg did not, but the 500 mg dose lowered plasma acylcarnitines and activated mitochondrial gene sets in muscle while 1,000 mg did neither. That is not a dose-response curve. It is two doses doing overlapping, slightly different things, and paying double for the higher one buys you the endurance signal in people over 65 and nothing extra for strength.

"Urolithin A is a pomegranate extract."

It is a bacterial metabolite, and the thing in every capsule is made by chemical synthesis. Pomegranate contains ellagitannins, the raw material; your gut bacteria (if you have the right ones) turn that into urolithin A over a day or so (Selma et al., 2014, International Journal of Systematic and Evolutionary Microbiology). The urolithin A in supplements, branded or generic, is synthesized, and the safety toxicology was deliberately done on the synthetic molecule (Heilman et al., 2017, Food and Chemical Toxicology). A product that lists "pomegranate extract" or "ellagic acid" and says urolithin A on the front is selling you the precursor and hoping your microbiome does the rest.

"A cheap 'urolithin A' is the same molecule at a better price."

Sometimes. This is the myth that costs the most money, because the failure is invisible. A legitimate generic is identical to the branded form and can cost half as much per day. A bad one is a pomegranate extract in a costume, an underdosed capsule, or a label that was never checked against the bottle. When we tested 44 supplements bought on Amazon, enough of them missed their label claim that we stopped assuming any label is right by default (what we found when we tested 44 Amazon supplements). The only protection is a lot-specific certificate of analysis showing identity and potency, which is why we publish ours at the lab testing page. A brand that will not show you one for a $90 bottle has answered your question.

Mt. Angel Vitamins for Urolithin A: The Complete Guide

• Urolithin A 500mg – Cellular Energy & Mitochondrial Renewal – 60 Capsules

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• NMN + NR Cellular Wellness Supplement – Support Healthy NAD+ Levels, Mitochondrial Health & Longevity – with Resveratrol, TMG, BioPerine® & Zinc – 60 Capsules

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Frequently Asked Questions

What is urolithin A and where does it come from?

Urolithin A is a small molecule (3,8-dihydroxy-urolithin) that specific gut bacteria make from ellagitannins, plant tannins found in pomegranate, walnuts, raspberries, and strawberries. It is not present in any food; your microbiome either builds it or it does not. It matters because it is the best-studied natural activator of mitophagy, the process cells use to recycle worn-out mitochondria. The urolithin A in supplements is made by chemical synthesis, whether branded or generic. The full mechanism and every form on the market are covered in the [Urolithin A monograph](/ingredients/urolithin-a).

Why can most people not make urolithin A from pomegranate?

Because the conversion needs particular gut bacteria, such as Gordonibacter urolithinfaciens, that many adults do not carry in useful numbers. In a 100-person study, only about 40% converted a glass of pomegranate juice into a meaningful amount of urolithin A, and only 12% had any in their blood at baseline (Singh et al., 2021, European Journal of Clinical Nutrition). Researchers group people into metabotypes: A (makes it), B (makes it plus related urolithins), and 0 (makes none). Age is the strongest known predictor of which group you are in, and there is no consumer test to find out.

What does mitophagy mean in plain English?

Mitophagy is your cells taking out the trash, specifically the worn-out mitochondria. Mitochondria are the structures that turn food and oxygen into usable energy. They wear out, and a damaged one leaks and produces less energy per unit of fuel. Mitophagy tags the damaged mitochondrion, wraps it, breaks it down, and reuses the parts, which makes room for new ones. The process slows with age, so damaged mitochondria accumulate. Urolithin A nudges the tagging system (called PINK1/Parkin) back on; a 2022 trial saw those proteins rise in human muscle biopsies after four months at 500 mg.

What did the human trials of urolithin A measure and find?

Six randomized, placebo-controlled trials, all four weeks to four months long. The headline: in 88 sedentary adults aged 40 to 64, four months of 500 mg raised hamstring strength 12% versus placebo, while the placebo group lost about 10% (Singh et al., 2022, Cell Reports Medicine). In 66 adults aged 65 to 90, 1,000 mg improved muscle endurance at two months (Liu et al., 2022, JAMA Network Open). Blood markers of mitochondrial efficiency and inflammation fell in both. Primary endpoints missed in both trials (peak power, six-minute walk). A 2025 trial in trained 27-year-old runners found no performance gain. See [the trial data as charts](/research/urolithin-a-clinical-data-visual).

What dose did the trials use, and does 1,000 mg beat 500 mg?

The trials used 500 mg and 1,000 mg a day. For strength, 1,000 mg did not beat 500 mg: hamstring strength rose 12% at 500 mg and 9.8% at 1,000 mg, statistically the same (Singh et al., 2022). The higher dose produced within-group gains in aerobic capacity and walk distance that did not beat placebo; the lower dose lowered plasma acylcarnitines and activated mitochondrial genes in muscle while the higher dose did not. The over-65 endurance trial used only 1,000 mg. Practical reading: 500 mg for strength at 40 to 64; 1,000 mg if you are over 65 and endurance is the goal. Details at [where the dose-response curve flattens](/research/urolithin-a-dosage-diminishing-returns).

How long before muscle endurance changes were seen?

Two months. In the trial of 66 adults aged 65 to 90, muscle endurance (contractions to fatigue in a hand and a shin muscle) separated from placebo at the two-month visit and held at four months on 1,000 mg a day (Liu et al., 2022, JAMA Network Open). Strength and aerobic measures in the 40-to-64 trial were assessed at four months, a window chosen because muscle tissue takes that long to remodel (Singh et al., 2022). Blood biomarkers shifted within four weeks (Andreux et al., 2019, Nature Metabolism). Nothing in any trial suggests you will feel a change in the first week.

Is urolithin A safe long term?

Short term, the record is clean: a 90-day rat study found no toxic effect at the highest dose tested, more than 3,400 mg per kilogram of body weight per day (Heilman et al., 2017), the FDA issued a no-questions letter on GRAS notice GRN 791 in December 2018, and adverse events matched placebo in trials up to four months. Long term is unknown. The longest human exposure in any published trial is four months; there is no one-year or five-year data in people. Taking it for years is a reasonable choice as long as you know you are ahead of the evidence when you make it.

Mitopure vs generic urolithin A: what is the real difference?

The molecule is identical; both are synthetic 3,8-dihydroxy-urolithin. Mitopure is Amazentis's branded form, sold by Timeline, and Amazentis scientists co-authored every human trial. It carries NSF Certified for Sport status and costs about $3.30 a day ($99 for 60 softgels, two a day for 500 mg, verified October 13, 2026). A legitimate generic gives you the same 500 mg for less; a bad one is a pomegranate extract or an underdosed capsule. The protection is a lot-specific certificate of analysis showing identity and potency. [The buying guide](/reviews/best-urolithin-a-supplements-buying-guide) ranks the US options, and Mitopure earns its place on it.

Who should not take urolithin A?

Anyone pregnant or breastfeeding, because there is no data in either group. Children and teenagers, for the same reason. People on daily prescriptions should ask the prescriber first: the main trial excluded anyone on statins, blood thinners, steroids, or thyroid medication, so no interaction data exists for those drugs. Anyone with a diagnosed muscle, heart, liver, kidney, or immune condition should treat this as a clinician conversation, since every trial enrolled healthy volunteers. And anyone whose weakness or fatigue came on over weeks rather than years should get that evaluated rather than supplement past it.

Does urolithin A do anything for people under 40?

The one trial in that age group says not much. Forty-two competitive male distance runners, average age 27, took 1,000 mg or placebo for four weeks during an altitude camp. Their 3,000 m time trial did not improve, and VO2max gains did not separate from placebo. Perceived exertion and a muscle-damage marker (creatine kinase) after the time trial were lower (Whitfield et al., 2025, Sports Medicine). A healthy, active 30-year-old has not yet lost much mitophagy capacity, so there is less for urolithin A to restore. A sedentary 35-year-old sits in a gap no trial has covered; the closest evidence is the 40-to-64 study in people who did not exercise.

Deep Dives

• Mitopure vs Mt. Angel Urolithin A: Which Should You Buy? — Same molecule, same 500 mg dose, so the verdict is about fit. Timeline's Mitopure ($3.30 a day) is the material used in every published human trial. Mt. Angel's capsule ($1.50 a day) carries a third-party assay on its raw-material lot. Pay for Mitopure if the trial record on the label matters; otherwise buy the trial dose for less than half.
• Urolithin A vs NMN: Different Mechanisms, Which One First? — Start with urolithin A if your goal is muscle endurance or strength after 40; start with NMN if you want the cheaper, faster-to-measure lever on NAD+. They work on different parts of the mitochondrion, no trial has ever compared them head to head, and the honest default for most people is one at a time, not both at once.
• Best Urolithin A Supplements in the US (2026 Buyer's Guide) — We compared the Urolithin A supplements actually available in the US on the things that matter: dose versus the clinical research, purity and third-party testing, manufacturing transparency, and real cost per day. Here's what we recommend and why, including our own and the competitors we respect.
• Urolithin A Dosage: The Plateau Effect & Diminishing Returns — Interactive dose-response analysis showing why 500-1000mg of urolithin A is optimal and where diminishing returns begin.
• Urolithin A Clinical Data: An Interactive Visual Guide — Interactive visualizations of urolithin A clinical trial data including mitophagy mechanism, muscle endurance improvements, biomarker reductions, and ATP production scatter analysis.
• Mitochondrial Quality Control and the Clinical Application of Urolithin A — A comprehensive clinical analysis of Urolithin A, a postbiotic metabolite that activates mitophagy through the PINK1/Parkin signaling pathway. Covers biosynthesis via the gut microbiome, human clinical trial data for muscle endurance and immune function, metabolic and neuroprotective research, pharmacokinetics, and safety.