Supplement: Urolithine A

What It Is

Your gut bacteria build urolithin A; no food contains it ready-made. Bacteria in the large intestine break the ellagitannins in pomegranate, walnuts, strawberries, raspberries and some other fruits into ellagic acid, then into urolithins. Of the urolithins, researchers focus on urolithin A.

From Food to Urolithin A

1The precursors in food

The raw material is a group of compounds called ellagitannins, concentrated in pomegranate, walnuts, and berries such as strawberries and raspberries. On their own these are poorly absorbed. Eating those foods gives your gut the raw ellagitannins, and the bacteria do the rest.

2The gut bacteria make the conversion

Bacteria in the large intestine convert ellagitannins into ellagic acid and then into urolithins, including urolithin A. This is a microbial step, so it depends on which bacteria you carry. It is the same reason two people can eat the same pomegranate and end up with very different amounts.

3Converter and low-producer microbiomes

Researchers group people into urolithin metabotypes. Many produce urolithin A well, while a minority produce very little. Which group you fall into shifts with age, diet and gut health. A low producer gets less benefit from the food precursors, which is the reason the compound is also made as a direct supplement.

What It Does

Its clearest human signal is in muscle. In middle-aged adults, strength rose about 12%; in adults aged 65 to 90, endurance improved.

Both of the largest human trials missed their pre-registered primary endpoint; the strength and endurance gains came on secondary measures instead.

One missed on peak power output; the other on 6-minute walk distance and muscle ATP production.

In people, urolithin A reliably shifts muscle mitochondrial genes and blood markers toward healthier mitochondria. The markers moved; whether people actually got stronger is the weaker part of the record.

Reaching published, randomized human trials is unusual in the biology of aging, and urolithin A has cleared that bar. The human evidence is still early, but the animal mechanism is strong enough to make better human research worth watching.

The Research & Studies

Everything here is based on the research we have collected and checked, sorted into groups and ordered with the strongest evidence first. Click any claim to open the studies behind it.

How it works

Urolithin A switches on mitophagy, the cell's cleanup of damaged mitochondriaModerate · mixed

In plain terms

In lab animals, urolithin A switches on the cellular cleanup that clears out damaged mitochondria, and that came with longer life in worms and better muscle in old mice.

In detail

Ryu and colleagues (2016, Nature Medicine) showed that urolithin A induces mitophagy across model systems: it extended lifespan in C. elegans and improved running endurance and grip strength in aged rodents, with the effect traced to enhanced clearance of dysfunctional mitochondria. The molecular case for mitophagy is the most robust part of the urolithin A story, and it is why the compound was carried into human trials.

The study · 1

Ryu 2016, Nature Medicine · Nature Medicine

Counts once: this finding and 1 other here come from the same source, so they are one body of evidence, not separate confirmations.

Your gut bacteria make urolithin A from food, and not everyone makes muchModerate · mixed

In plain terms

You do not eat urolithin A itself; your gut bacteria build it from pomegranate, walnuts and berries, and not everyone carries the bacteria to make much.

In detail

Tomás-Barberán and colleagues (2017, Molecular Nutrition and Food Research) set out the urolithin metabotype concept: after eating ellagitannin-rich foods, individuals cluster into metabotype A (producing urolithin A), metabotype B (also producing isourolithin A and urolithin B) and metabotype 0 (producing little to none). Which group a person falls into depends on the composition of their gut microbiota and shifts with age, diet and health, which is the core rationale for supplementing the metabolite directly.

The study · 1

Tomas-Barberan 2017, Mol Nutr Food Res · Molecular Nutrition and Food Research

500 mg and 1,000 mg shifted muscle mitochondrial genes and blood markers in 4 weeksEmerging

In plain terms

In the first human study, urolithin A changed muscle gene activity and blood markers in a way that points toward healthier mitochondria.

In detail

Andreux and colleagues (2019, Nature Metabolism) ran the first-in-human trial of urolithin A in healthy, sedentary elderly adults, dosing single and repeated administrations over four weeks. Urolithin A was bioavailable at all doses, and 500 mg and 1,000 mg modulated plasma acylcarnitines and skeletal-muscle mitochondrial gene expression, which the authors interpreted as a molecular signature of improved mitochondrial function. These were secondary outcomes; the primary outcome was safety.

The study · 1

Andreux 2019, Nature Metabolism · Nature Metabolism

Muscle And Strength

More muscle contractions before fatigue in adults aged 65 to 90Emerging

In plain terms

Older adults on urolithin A could do more muscle contractions before tiring, though the trial's main measures, walking distance and a direct muscle-energy readout, did not clearly improve.

In detail

Liu and colleagues (2022, JAMA Network Open) randomized 66 adults aged 65 to 90 (about 76% women, all White) to 1,000 mg urolithin A or placebo daily for four months. Muscle endurance, measured as contractions to fatigue in the first dorsal interosseus and tibialis anterior, improved significantly versus placebo at two months. The two primary endpoints, change in 6-minute walk distance and maximal ATP production in the hand muscle, did not reach statistical significance, though both trended in favor of urolithin A.

The study · 1

Liu 2022, JAMA Netw Open · JAMA Network Open

Counts once: this finding and 1 other here come from the same source, so they are one body of evidence, not separate confirmations.

Muscle strength rose about 12% in middle-aged adults over four monthsPreliminary

In plain terms

Middle-aged adults who took urolithin A for four months got roughly 12% stronger, though the trial did not hit its main pre-chosen goal of peak power.

In detail

Singh and colleagues (2022, Cell Reports Medicine) ran a randomized, placebo-controlled trial of urolithin A (marketed as Mitopure) at two doses for four months in middle-aged adults (NCT03464500). Muscle strength rose by about 12%, and skeletal-muscle expression of proteins linked to mitophagy and mitochondrial metabolism increased significantly. The pre-registered primary endpoint, peak power output, did not improve significantly, so the strength result sits among the secondary outcomes.

The study · 1

Singh 2022, Cell Rep Med · Cell Reports Medicine

Counts once: this finding and 1 other here come from the same source, so they are one body of evidence, not separate confirmations.

Cardiorespiratory Fitness

Better aerobic endurance and 6-minute walk distance in the same middle-aged trialEmerging

In plain terms

The same middle-aged trial saw better aerobic endurance and longer walking distance on urolithin A.

In detail

Alongside the strength result, Singh and colleagues (2022, Cell Reports Medicine) reported clinically meaningful gains in aerobic endurance (peak VO2) and physical performance (6-minute walk test) with urolithin A versus placebo over four months. As with the strength finding, these were secondary outcomes in a trial whose pre-registered primary endpoint of peak power output was not met.

The study · 1

Singh 2022, Cell Rep Med · Cell Reports Medicine

Counts once: this finding and 1 other here come from the same source, so they are one body of evidence, not separate confirmations.

Immune Function

Urolithin A lowered C-reactive protein, a blood marker of inflammationEmerging

In plain terms

Urolithin A nudged down a common blood marker of inflammation.

In detail

In Liu and colleagues (2022, JAMA Network Open), plasma C-reactive protein, several acylcarnitines and ceramides were reduced with urolithin A relative to placebo over four months. Lower acylcarnitines are read as more complete fat oxidation, and lower C-reactive protein as reduced systemic inflammation, both pointing the same way as the muscle findings.

The study · 1

Liu 2022, JAMA Netw Open · JAMA Network Open

Counts once: this finding and 1 other here come from the same source, so they are one body of evidence, not separate confirmations.

Longevity And Mortality

No human study has shown urolithin A slows aging or extends lifePreliminary · mixed

In plain terms

The longer-life claims come from worms and mice; no human study has shown urolithin A slows aging or extends life.

In detail

The lifespan evidence is animal: Ryu and colleagues (2016, Nature Medicine) reported extended lifespan in C. elegans and improved muscle in aged rodents. Human trials to date reach muscle strength and endurance measures and mitochondrial biomarkers over weeks to months. No human study has used lifespan, incident disease or a validated aging endpoint, so anti-aging benefit in people is extrapolation from mechanism and animal work.

The study · 1

Ryu 2016, Nature Medicine · Nature Medicine

Counts once: this finding and 1 other here come from the same source, so they are one body of evidence, not separate confirmations.

Cognition

Brain benefits appear in animal and cell studies, not yet in peoplePreliminary · mixed

In plain terms

Animal and cell studies hint at brain benefits, but no human trial has shown urolithin A helps memory or thinking.

In detail

Garcia-Villalba and colleagues (2023, Molecular Aspects of Medicine) review ellagitannins, urolithins and neuroprotection, describing preclinical mechanisms including enhanced mitophagy and lower neuroinflammation, and discussing the possible link to the gut microbiome. The human evidence for cognitive outcomes specific to urolithin A remains at an early stage, so this belongs at the preliminary end of the ladder.

The study · 1

Garcia-Villalba 2023, Mol Aspects Med · Molecular Aspects of Medicine

How It Works

Mitophagy is the cell's quality-control step: it tags a spent mitochondrion and recycles it, freeing room for a healthy replacement. It is one branch of autophagy, aimed only at mitochondria, and urolithin A raises its rate.

The animal evidence is the sturdiest part of the case. In worms and rodents, urolithin A induced mitophagy and improved muscle function in aged animals; in the worm C. elegans, it extended lifespan.

Muscle is dense with mitochondria, and its capacity tracks their quality. Clearing damaged mitochondria leaves older muscle with a healthier population. That predicts better endurance and strength where cleanup has slowed. The two largest trials set out to test that prediction in people.

Getting It Right

Urolithin A reaches you two ways: the food precursors your gut converts, or the direct supplement.

Ways to Do It

Urolithin A can come from food precursors, from the direct supplement, or both. The right approach depends partly on whether your gut makes much of it. Keep your expectations matched to what the trials showed.

1

Eat the food precursors$Easy

Pomegranate, walnuts, strawberries and raspberries supply the ellagitannins your gut turns into urolithins. These are good foods on their own merits, and for a person who converts well they provide a steady, free source. This is the first and most sensible step, and it brings fiber and other nutrients along with it.

2

Know that conversion varies$Easy

Many people make urolithin A well from those foods, and a minority make very little. There is no simple home test, and the amount shifts with age, diet and gut health. If you eat plenty of pomegranate and walnuts and feel no different, low conversion is one plausible reason, and it is the situation the direct supplement was designed for.

3

The studied form and dose$$Easy

The human trials used direct urolithin A, sold as Mitopure, which sidesteps the conversion step. The doses studied were 500 mg and 1,000 mg a day, taken for four weeks to four months.

4

Consider who the trials actually studied$Moderate

The benefits were measured in middle-aged and older adults focused on muscle and endurance, many of them already reasonably active. If that describes you, the muscle and endurance signals are the part of the evidence that applies. The trials did not study young, healthy people who already convert food well.

5

Match expectations to the evidenceFreeEasy

The trials support modest gains in muscle strength and endurance, plus healthier mitochondrial markers, over months. They do not reach a longevity result; that rests on animal data. Treat it as a possible edge on muscle and energy, and keep training as the lever with the strongest evidence for the same goals.

Go Deeper

Related topics:

• Mitochondria and energy, the organelles the cleanup targets.
• The biology of aging, how mitochondrial quality fits the wider process.
• Protein and muscle, the raw material muscle is built from.
• Resistance training, the direct way to build strength.

The Chinese Medicine View

Urolithin A was described only this century, so the classical pharmacopoeia never assigned it a channel, a temperature or a flavour, and it has no traditional preparation. The tradition can still offer a lens, and two of its ideas map onto what the compound does.

Chinese medicine treats stagnation, the buildup of what the body should have cleared, as a root of many disease patterns. Mitophagy is the cellular version of that idea.

The tradition also ties aging to the Kidney and its store of Jing, the deep constitutional reserve drawn down across a lifetime. Classical signs of declining Jing (waning vitality, weakening bones, lost strength) track closely with what a modern account calls aging. A substance tied to cellular renewal and muscular vigor maps naturally onto Kidney and Jing.

A practitioner would not treat urolithin A as a classical tonic. The framework does not hold that more of a supporting substance is better. It would read the whole-food route (pomegranate, walnuts and berries in a varied diet) as squarely in keeping with nourishing life. The compound draws no authority from the tradition; its evidence stands on the trials.

Five limits temper the muscle findings.

Cautions For This Practice

Extra restraint

Everything to be aware of is here, in one place. This practice suits most healthy people; a few situations call for real care.

No more side effects than placebo at up to 1,000 mg a day for 4 months

Safety was the pre-set primary outcome of the first-in-human trial (Andreux 2019, Nature Metabolism), where urolithin A was found safe and bioavailable at doses up to 1,000 mg. In the 4-month older-adult trial (Liu 2022, JAMA Network Open), no statistical difference in adverse events was seen between urolithin A and placebo, and the compound was described as safe and well tolerated. Both were short trials in small groups.Andreux 2019, Nature MetabolismLiu 2022, JAMA Netw Open

Early and often industry-funded evidence

The human trials to date are small, and several were run or co-authored by the maker of Mitopure. That does not make the findings wrong. Small sponsored trials are where effects tend to look largest, so treat the muscle numbers as early rather than settled.

Long-term use has not been studied

The trials ran for weeks to a few months. Urolithin A was well tolerated over those periods; what happens with daily use over years has not been measured.

Pregnancy and breastfeeding are untested

There is no trial data on urolithin A supplements during pregnancy or breastfeeding. Getting its food precursors is part of a normal diet; a concentrated supplement during these periods is a question for your clinician.

It is not a longevity guarantee

In people, urolithin A has shown no effect on aging or lifespan. Any anti-aging promise on a label runs past what the human trials have measured.

Medication and condition interactions are not characterized

Formal interaction studies with common medications are lacking. If you take prescription drugs or manage a chronic condition, a word with your pharmacist or clinician before adding a concentrated supplement is sensible.

Start slow, be smart, read the research, and consult a professional if you have any concerns. This is here to inform your choice, not make it for you.

Common Questions

How is urolithin A different from taking pomegranate extract?

Pomegranate extract gives you ellagitannins and ellagic acid, the precursor. Your gut still has to convert that into urolithin A, and a minority of people do so poorly. Direct urolithin A, the Mitopure form used in the trials, is the finished compound, so it skips the conversion step.

Does urolithin A build muscle?

Modestly. Trials found small gains in strength and endurance. If muscle is the aim, resistance training and enough protein are what actually build it, and urolithin A is at most a small addition.

Can I get urolithin A from food like pomegranate?

Yes, if your gut converts it. The food gives your bacteria the raw material. How much becomes urolithin A depends on the bacteria you carry, and a minority produce very little. There is no simple home test.

Is urolithin A safe?

Over the short term, yes. Safety was the main goal of the first human study, which found the compound well tolerated. A four-month trial in older adults saw no more side effects than placebo at up to 1,000 mg a day. The open questions are long-term use and pregnancy, both untested.

Does urolithin A slow aging or extend life?

No, the lifespan gains are in worms and rodents. Those results make urolithin A worth testing further in people, but the marketing runs well ahead of the human evidence.