Urolithin A (Mitopure): Mitophagy, Muscle and Aging (2026 Evidence Review)

Key Takeaways

Urolithin A raised mitophagy-related proteins in human muscle in a controlled trial (Singh et al., 2022), which is unusual for a supplement. The evidence is still thin, though. A 2026 review counted five small muscle trials with 236 participants in total (Dao et al., 2026), and the two largest missed their primary endpoints while improving secondary measures such as strength and endurance (Singh et al., 2022; Liu et al., 2022). Most people cannot make much urolithin A from food: in a pomegranate-juice study only about 40% of participants converted the juice's precursors in meaningful amounts (Singh et al., 2022b). Two recent trials without industry ties add some independent data (Zhao et al., 2024; da Costa Pinaffi-Langley et al., 2026).

What is urolithin A?

Urolithin A is made by gut bacteria from ellagitannins, plant polyphenols found in pomegranates, walnuts and some berries. How much you make depends on your microbiome. In one study, 12% of participants had detectable urolithin A at baseline, and about 40% converted pomegranate-juice precursors into it after drinking the juice (Singh et al., 2022b).

That variability is why Amazentis developed a purified form, sold as Mitopure. In the same study, taking urolithin A directly raised plasma levels and gave more than six times the exposure that pomegranate juice did (Singh et al., 2022b). Amazentis scientists ran that study, and the same is true of most trials discussed below, so the funding question gets its own section.

On the regulatory side, Amazentis notified the FDA that it considers urolithin A generally recognized as safe (GRAS) for use in certain foods, and the agency replied that it had no questions about that conclusion (FDA, GRN 791). A "no questions" letter concerns safety under the stated conditions of use. It says nothing about health benefits.

How does urolithin A activate mitophagy?

Mitophagy is how cells break down worn-out mitochondria so they can be replaced. In worms, urolithin A induced mitophagy, stopped dysfunctional mitochondria from piling up with age and extended lifespan. In mice and rats it improved exercise capacity (Ryu et al., 2016).

Cells flag damaged mitochondria for disposal through signaling proteins, the best known being PINK1 and Parkin. With age the clean-up slows. Faulty mitochondria accumulate, make less ATP and leak more reactive oxygen species. The supplement is meant to restart the clean-up. That is a different job from adding fuel, as NAD+ precursors do, or mopping up oxidants, as antioxidants do.

The human evidence for the mechanism comes from blood and muscle samples. In the first human trial, 4 weeks at 500 mg or 1,000 mg a day shifted mitochondrial gene expression in skeletal muscle and lowered plasma acylcarnitines, markers of how fat is burned (Andreux et al., 2019). In a 4-month trial, proteins linked to mitophagy and mitochondrial metabolism rose significantly in muscle biopsies (Singh et al., 2022). Both trials came from Amazentis.

The 2016 paper that started the field was a collaboration between EPFL researchers and Amazentis scientists (Ryu et al., 2016). Worms and rodents generate hypotheses. They do not tell anyone how much a 55-year-old will benefit.

Why do only some people produce urolithin A naturally?

Converting ellagitannins into urolithin A takes particular gut bacteria, and many people do not carry enough of them. In the pomegranate-juice study, producers had higher gut microbiome diversity and a higher ratio of Firmicutes to Bacteroides than non-producers (Singh et al., 2022b).

Researchers sort people into urolithin "metabotypes" according to which urolithins their bacteria make. Hu and colleagues name this person-to-person variation as one reason trial results are hard to read: two people eating the same walnuts can end up with very different exposure (Hu et al., 2026).

Supplementing directly removes the microbiome from the equation, which is the whole commercial rationale. The same review flags a question that is still open. Urolithin A circulates in free and conjugated forms, and it is not settled which form does the work in tissue, or whether a capsule behaves exactly like urolithin A made in the gut (Hu et al., 2026).

What does the human trial evidence show?

The 2026 review by Dao and colleagues found five randomized trials, 236 participants in all, that measured muscle outcomes (Dao et al., 2026). The two largest missed their primary endpoints but improved secondary measures: muscle strength in middle-aged adults and muscle endurance in older adults (Singh et al., 2022; Liu et al., 2022).

Muscle strength and endurance

In a 4-month trial, middle-aged adults took Mitopure at one of two doses or placebo. Muscle strength rose by about 12%, and the authors described clinically meaningful gains in peak oxygen uptake and 6-minute walk distance. Peak power output, the primary endpoint, did not improve significantly. Plasma acylcarnitines and C-reactive protein fell (Singh et al., 2022).

A second 4-month trial gave 66 older adults, mean age 71.7, either 1,000 mg a day or placebo. Its primary endpoints were the change in 6-minute walk distance and maximal ATP production in a hand muscle. Neither differed significantly from placebo. Muscle endurance in a hand muscle and a leg muscle did improve, and several plasma markers, including C-reactive protein, came down (Liu et al., 2022).

When the 2026 review pooled the two trials that measured walking distance, urolithin A added an average of 17 meters over placebo, a difference that was not statistically significant (p = 0.135). The review rated the certainty of that evidence as low (Dao et al., 2026).

A smaller 8-week trial in resistance-trained young men, run without industry ties, found significant gains over placebo in maximal isometric strength and repetitions to failure. One-rep max bench press and squat did not differ from placebo (Zhao et al., 2024).

Team sport performance

In elite academy soccer players, six weeks of urolithin A during preseason improved distance on the Yo-Yo intermittent recovery test by 239 meters more than placebo (p = 0.048) and countermovement jump height by 3.3 cm. Sprint speed, jump power and other jump measures did not differ. Antioxidant activity in saliva fell over the preseason in the placebo group but held steady with urolithin A (Monsalve Acevedo et al., 2025). The margin on the main outcome was narrow, and the team was small, so this is a lead worth testing again rather than a settled result.

Exercise recovery

In well-trained runners, urolithin A did not improve 3,000 m time-trial performance. It did lower perceived exertion and post-race creatine kinase, a muscle damage marker, compared with placebo. VO2max rose 5.4% within the urolithin A group, but the difference between groups was not significant. Muscle biopsies showed mitochondrial pathways turned up and inflammatory pathways turned down (Whitfield et al., 2025). Amazentis funded the study.

Immune function

A 2025 trial in Nature Aging gave 50 healthy middle-aged adults 1,000 mg a day or placebo for 4 weeks. Urolithin A expanded naive-like, less exhausted CD8+ T cells, the primary outcome, and increased their capacity to burn fat for fuel (Denk et al., 2025). These are measurements of immune cells, not of how often people got sick. Amazentis funded the trial and supplied the product.

Blood flow in the brain

A 2026 JAMA Network Open trial gave 50 middle-aged adults with obesity urolithin A or placebo for 28 days. Endothelial function in the arm did not change. Task-evoked blood-flow responses in the brain rose more with urolithin A than with placebo, while task performance stayed the same (da Costa Pinaffi-Langley et al., 2026). The authors reported no conflicts of interest.

Why does mitophagy matter for aging muscle?

Muscle runs on mitochondria, and the system that clears damaged ones slows with age. A 2024 review by Amazentis scientists describes declining mitophagy as one way aging erodes skeletal muscle performance (Faitg et al., 2024).

Cells keep their mitochondria healthy in three ways: building new ones, constantly splitting and merging existing ones, and removing the damaged ones through mitophagy. When removal falls behind, faulty mitochondria pile up, and muscle, with its heavy energy demand, feels it first (Faitg et al., 2024). That is the logic behind trying to restart mitophagy with urolithin A.

The review's authors work for the company that sells Mitopure, so read it as a statement of the hypothesis, not as independent confirmation. The independent evidence that mitophagy drives age-related muscle decline in people, and that boosting it reverses the decline, is still being built.

Why should you be cautious about urolithin A claims?

The trials are few, small and short, the biggest ones missed their primary endpoints, and most were sponsored by the company selling the product. The 2026 review counted 236 participants across five muscle trials and called the evidence limited (Dao et al., 2026).

A 2026 translational review, written by authors with no commercial ties, lists the open problems: how much urolithin A people make on their own, the difference between free and conjugated forms, unclear exposure-response relationships, large variation in who responds, and weaknesses in trial design. Its authors conclude that clinical usefulness depends on solving those problems first (Hu et al., 2026).

None of this makes urolithin A useless. Muscle biopsies show it changes mitochondrial biology in people (Singh et al., 2022; Andreux et al., 2019). Whether those changes add up to something you would notice, such as walking farther or recovering faster, is what the trials have not yet shown convincingly.

Who funded the urolithin A research?

Mostly Amazentis. The first-in-human trial, the 4-month middle-aged muscle trial and the immune trial list Amazentis employees among the authors or name the company as sponsor, and the running trial was funded by Amazentis (Andreux et al., 2019; Singh et al., 2022; Denk et al., 2025; Whitfield et al., 2025). Two recent trials, in trained young men and in adults with obesity, report no conflicts of interest (Zhao et al., 2024; da Costa Pinaffi-Langley et al., 2026).

Industry sponsorship does not make a result wrong. These are randomized, placebo-controlled trials in mainstream journals. The concern is narrower: when nearly all the positive data come from one source, nobody outside that source has yet confirmed the main muscle findings.

The two independent trials help a little. One found strength gains in trained men; the other found brain blood-flow changes but no vascular benefit in the arm (Zhao et al., 2024; da Costa Pinaffi-Langley et al., 2026). Both were small and short. What would settle the question is a larger independent trial, with a functional primary endpoint such as walking speed or strength, run for longer than 4 months.

How much urolithin A should you take?

Trials have used 500 mg and 1,000 mg a day (Andreux et al., 2019; Singh et al., 2022). The older-adult muscle trial and the immune trial both used 1,000 mg (Liu et al., 2022; Denk et al., 2025). No published analysis shows that the higher dose works better for a functional outcome.

The 2026 review combined the 500 mg and 1,000 mg arms of the middle-aged trial instead of comparing them, because the numbers were small (Dao et al., 2026). Trial lengths ran from 4 weeks to 4 months. If you try it, give it at least that long, and judge it by something you can measure, such as a timed walk or a grip-strength test.

Is urolithin A safe?

In the short term, it appears to be. The first human trial reported a favourable safety profile (Andreux et al., 2019), the 4-month older-adult trial found no difference in adverse events compared with placebo (Liu et al., 2022), and the 2026 obesity trial described it as well tolerated (da Costa Pinaffi-Langley et al., 2026).

Long-term data do not exist. No trial has run past 4 months, so the effect of years of stimulated mitophagy is unknown. Results on inflammation are also not uniform. C-reactive protein fell with urolithin A in two Amazentis trials (Singh et al., 2022; Liu et al., 2022), but rose within the urolithin A group over 8 weeks in the independent trial in trained men (Zhao et al., 2024). Heavy training may explain that, but it is a reminder that the picture is not settled.

Pregnant or breastfeeding women and people managing a serious illness have not been the focus of any trial. Talk to a doctor before adding it in those situations.

Does topical urolithin A work for skin?

Early results say possibly. In randomized, placebo-controlled studies, urolithin A applied to the skin reduced the depth of wrinkles around the eyes after 8 weeks and dampened redness after UVB exposure (D'Amico et al., 2026).

The same 2026 paper tested urolithin A in lab-grown human skin models and donated skin samples. It increased mitochondrial respiration and mitophagy markers, lowered inflammatory and aging-related markers, and raised proteins involved in the skin's structural matrix. A repeat patch test in people found no safety problems (D'Amico et al., 2026).

The research came from the Mitopure team, and topical use is a different product from the capsules discussed elsewhere in this article. Results for skin creams do not tell you anything about what swallowing urolithin A does for your muscles, or the reverse.

Can you get urolithin A from pomegranate juice?

Only if your gut bacteria cooperate. In the pomegranate-juice study, about 40% of participants converted its ellagitannins into urolithin A in meaningful amounts (Singh et al., 2022b). Most people cannot count on juice for a reliable dose.

Direct supplementation produced more than six times the exposure that juice did in the same study (Singh et al., 2022b). Pomegranates, walnuts and berries are still worth eating for their own sake. As a route to urolithin A, they are unreliable for the majority of people.

How does urolithin A compare with other mitochondrial supplements?

It works on a different step. CoQ10 carries electrons in the energy-producing chain, NMN raises NAD+, astaxanthin protects membranes from oxidation, and urolithin A targets the disposal of damaged mitochondria. No trial has tested any combination.

On strength of evidence the order is clear. CoQ10 has a 420-patient heart failure trial with fewer cardiovascular deaths (Mortensen et al., 2014). Creatine has the deepest muscle data of any supplement. For urolithin A, the record so far is human biomarker data plus a handful of small functional trials. For someone picking one thing to start with, creatine or CoQ10 will usually make more sense, with urolithin A as a later addition.

Our review of the hallmarks of aging places mitophagy alongside the other biological processes that decline with age, and ranks interventions by the quality of their human evidence.

Who might reasonably try urolithin A?

Adults who already cover the better-supported basics, exercise regularly, and want to target mitophagy while accepting that functional benefits are unproven. Trial participants so far have been middle-aged and older adults, trained young men and adults with obesity (Singh et al., 2022; Liu et al., 2022; Zhao et al., 2024; da Costa Pinaffi-Langley et al., 2026).

Buy the version that was studied. Most published trials used Mitopure, and generic urolithin A products have not been tested in published trials. Before starting, pick one outcome you can measure, such as 6-minute walk distance, grip strength or soreness after a standard workout, and re-test after 2 to 4 months.

Roughly 60% of people in the juice study did not convert ellagitannins well (Singh et al., 2022b). Those non-producers have the strongest theoretical case for supplementing, but no consumer test reliably tells you which group you are in.

What comes next for urolithin A research?

Bigger and longer trials with functional primary endpoints, more independent funding, and better ways to identify who responds. The 2026 translational review calls for metabotype-guided trials, better formulations and standardized biomarkers (Hu et al., 2026).

Two threads stand out. The immune findings, if confirmed with clinical outcomes, would matter well beyond muscle (Denk et al., 2025). The brain blood-flow signal in adults with obesity also deserves follow-up (da Costa Pinaffi-Langley et al., 2026). Each needs outcomes people actually experience, such as infection rates or cognitive change over time, before it means much for an individual.

Frequently Asked Questions

References

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