Supplement: Urolithin A

What It Is

Urolithin A is a small molecule that your own gut bacteria produce when you eat certain plants. It is a metabolite: it is not present in the food itself but is made downstream. Bacteria in the large intestine break down ellagitannins, found in pomegranate, walnuts, strawberries, raspberries and some other fruits, into ellagic acid and then into urolithins. Urolithin A is the one that has drawn the research, because it stimulates mitophagy, the process a cell uses to recycle its worn-out mitochondria, the structures that turn food and oxygen into usable energy. That single action is why it is studied for muscle, energy and aging.

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 starting material, not the finished compound.

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, and 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

Urolithin A has reached published, randomized human trials, which is unusual for a compound in the longevity conversation. The evidence sits at three levels, and they do not carry equal weight.

The sturdiest level is preclinical. In cells, worms and rodents, urolithin A activates mitophagy, and that is the mechanism the human work was built to test. Above the animal data but below any settled human outcome sit the biomarkers: in people, urolithin A reliably shifts muscle mitochondrial genes and blood markers toward healthier mitochondria. A marker moving is not the same as a person feeling better, so these results support the mechanism without proving a benefit anyone would notice.

The human functional results are the ones the marketing leans on, and they need the most care. The strength gain in middle-aged adults, about 12%, and the endurance gain in adults aged 65 to 90 were both secondary measures. Each of the two largest trials missed its pre-registered primary endpoint: peak power output in one, and 6-minute walk distance plus muscle ATP production in the other. Nearly every human trial was funded or co-authored by the company that sells the supplement. None of that makes the results wrong, and it is why they read as emerging signals and why regular training stays the strongest lever for the same goals, with urolithin A a possible addition to it.

No human trial has measured aging, lifespan or any outcome over years; the claim that urolithin A renews your cells and adds years rests on worms and mice.

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

Underneath every claim on this page is one mechanism: mitophagy. Mitochondria wear out, and a cell that cannot clear the damaged ones fills with machinery that makes energy poorly and leaks stress signals. Mitophagy is the quality-control step that tags a spent mitochondrion and recycles it, freeing room for healthy replacements. It is a specialized form of autophagy, the cell's general recycling process, aimed at mitochondria. Urolithin A raises the rate of this cleanup, and the preclinical evidence for that is the strongest part of the case: in worms and rodents it induced mitophagy, extended lifespan in C. elegans, and improved muscle function in aged animals.

Muscle is dense with mitochondria, and its capacity depends on their quality, which is covered in depth on mitochondria and energy. Clearing damaged mitochondria leaves older muscle with a healthier population of them, which would predict better endurance and strength where the cleanup has slowed. That is the chain the human trials set out to test, and it is why urolithin A sits next to exercise, protein and muscle, and resistance training.

Getting It Right

Ways to Do It

Urolithin A can come from food precursors, from the direct supplement, or both, and the right approach depends partly on whether your own gut makes much of it. The studied form and dose are stated below as fact, so you can weigh any product against them. 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 comes with the fiber and other nutrients a capsule leaves out.

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, stated plainly$$Easy

The human trials used direct urolithin A, sold under the branded form Mitopure, which sidesteps the conversion step entirely. The doses studied were 500 mg and 1,000 mg a day, taken for four weeks to four months. This is a factual description of what was tested, so you can compare any product against the trial evidence.

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 is you, the muscle and endurance signals are the part of the evidence that applies. A young, healthy, well-converting person eating these fruits already has less obvious room for the supplement to add.

5

Match expectations to the evidenceFreeEasy

The trials support modest gains in muscle strength and endurance and healthier mitochondrial markers over months. They do not reach a longevity or anti-aging result; that rests on animal data. Treat it as a possible edge on muscle and energy, keep training as the proven lever, and review whether it is doing anything for you.

Go Deeper

• Mitochondria and energy: the machinery urolithin A acts on, why mitochondrial quality sets muscle capacity, and why building mitochondria through training rests on far stronger evidence than any supplement.
• The biology of aging: where mitochondrial decline sits among the hallmarks of aging, and why the anti-aging molecules, urolithin A among them, are earlier than the marketing suggests.
• Protein and muscle: the dietary foundation for holding onto muscle, the outcome urolithin A is most studied for.
• Resistance training: the lever with the strongest evidence for muscle strength and healthy aging, which urolithin A can add to.

The Chinese Medicine View

Urolithin A was described only in this century, so it has no place in the classical Chinese pharmacopoeia. There is no channel it enters, no temperature or flavour a historical text assigned to it, and no traditional preparation. What follows places it inside the framework as a lens, and it invents no classical words about a compound the tradition did not see.

Two of the tradition's ideas sit near where urolithin A acts. The first is the theme of renewal and clearing the old to make room for the new. Chinese medicine reads health partly as the free turnover of what the body no longer needs, and the accumulation of the stale and stagnant as the root of many patterns. Mitophagy, the clearing of spent mitochondria so healthy ones can take their place, is a close version of that idea at the level of the cell.

The second idea is the Kidney and its store of Jing, the essence, thought of as the deep constitutional reserve drawn down across a lifetime. The classical signs of declining Jing, waning vitality, weakening bones, and loss of strength, are close to what a modern account calls aging, and this is the same territory covered on the biology of aging. A substance associated with cellular renewal and muscular vigor maps naturally onto the Kidney and Jing in this framing.

A practitioner would not treat urolithin A as a classical tonic, and the tradition's own caution applies. The framework does not hold that more of a supporting substance is better, and it would read the whole-food route, pomegranate and walnuts and berries as part of a varied diet, as more in keeping with nourishing life than a concentrated extract taken on its own. The mapping is a bridge to the rest of the library. The compound draws no authority from the tradition; its evidence stands on the trials.

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 company that makes the supplement. That does not make the findings wrong. Small sponsored trials are where effects tend to look largest, and two of the studies missed their main pre-registered endpoint, so read the muscle numbers as emerging.

Long-term use has not been studied

The trials ran for weeks to a few months. Urolithin A was well tolerated over those periods, and what happens with daily use over years has not been measured. A reasonable stance is to set a review point every few months and decide again then.

Pregnancy and breastfeeding are untested

There is no trial data on urolithin A supplements during pregnancy or breastfeeding. Getting the food precursors from pomegranate, walnuts and berries is part of a normal diet; a concentrated supplement in these periods is a question for your clinician.

It is not a longevity guarantee

The lifespan results come from worms and mice. In people, urolithin A has shifted mitochondrial biomarkers and shown modest muscle signals, and it has not been shown to slow aging or extend life. Regular training remains the lever with the strongest evidence for the same goals.

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

What is urolithin A?

Urolithin A is a compound your gut bacteria make when you eat foods rich in ellagitannins, such as pomegranate, walnuts and berries. It is not in the food itself; bacteria in the large intestine convert the plant compounds into it. Its notable action is stimulating mitophagy, the cellular process that clears out damaged mitochondria so healthier ones can take their place, which is why it is studied for muscle, energy and aging.

Does urolithin A build muscle?

The early human evidence points that way, modestly. In a four-month trial in middle-aged adults, muscle strength rose about 12% and aerobic endurance improved, and in a trial in adults aged 65 to 90, muscle endurance improved. Both trials missed their main pre-chosen goal while succeeding on secondary measures, both were small, and company scientists were involved, so the muscle benefit is graded emerging. It is best thought of as a possible addition to training, which stays the proven lever.

Can I get urolithin A from food like pomegranate?

Sometimes, and it depends on your gut. Pomegranate, walnuts and berries provide the precursors, and whether you turn them into much urolithin A depends on the bacteria you carry. Many people convert well; a minority make very little, and there is no simple home test. Eating those foods is worthwhile regardless, and if you convert well they are a free, steady source. Low conversion is the situation the direct supplement was designed to address.

Is urolithin A safe?

In the trials so far, yes, over the short term. Safety was the main goal of the first human study, which found it well tolerated, and a four-month trial in older adults saw no more side effects than placebo at up to 1,000 mg a day. Long-term data over years is missing, and there is no trial evidence in pregnancy or breastfeeding, so those situations call for a clinician's input.

Does urolithin A slow aging or extend life?

That has not been shown in people. The lifespan evidence comes from worms and mice; in humans, urolithin A has moved mitochondrial biomarkers and muscle measures over months, which is not the same as slowing aging or adding years. The anti-aging framing is an extrapolation from animal and mechanistic work. If longer, healthier life is the goal, the levers with the strongest evidence remain training, muscle and the ordinary daily habits, with urolithin A a promising early addition whose longevity benefit is not established.