Urolithin A is a compound produced when gut bacteria metabolize ellagitannins: polyphenols found in pomegranates, walnuts, and certain berries. Because not everyone’s microbiome converts these precursors efficiently, urolithin A supplements have attracted attention as a way to deliver the compound directly. Over the past few years, researchers have begun examining whether it can meaningfully support exercise performance and muscle health.
The biological rationale centers on mitophagy: a cellular housekeeping process that clears out damaged mitochondria so healthier ones can take their place. Mitochondria power muscle contractions, and their quality declines with age and heavy training loads. Urolithin A appears to activate this renewal pathway, which has led researchers to ask whether supplementation might translate into measurable gains in endurance, strength, or recovery, not just in older adults, but in trained athletes as well.
Key Takeaways
- Urolithin A activates mitophagy: a cellular process that clears damaged mitochondria and supports renewal of more efficient ones, which is the leading proposed mechanism for its effects on muscle health.
- A company-funded randomized trial in middle-aged adults missed its primary endpoint, peak power output; some secondary measures such as hamstring strength favoured urolithin A, but peak VO2 versus placebo was not significant (p = 0.058) [1].
- Evidence in trained athletes is more limited and less consistent; highly trained individuals may have less headroom for additional mitochondrial adaptation from a supplement [2].
- Preliminary data in athletes are mixed: one 8-week trial improved isometric force and repetitions to failure, a soccer pilot found no group differences in saliva antioxidant assays, and highly trained runners did not improve their time trial. Most trials are small and short-term [3][4][2].
- Individual responses likely vary based on gut microbiome composition, which affects how much urolithin A a person naturally produces from food.
The Mitochondrial Mechanism Behind Urolithin A
Mitochondria are the primary energy source for working muscles, but they accumulate damage over time. The cell has a built-in quality-control system called mitophagy: essentially, a selective recycling process that tags dysfunctional mitochondria for removal and replacement. When mitophagy slows down, damaged mitochondria accumulate, energy production becomes less efficient, and muscle fatigue sets in sooner.
Urolithin A is one of a small number of naturally occurring compounds shown to stimulate this mitophagy pathway. By promoting the clearance of worn-out mitochondria, it may help cells maintain a healthier, more efficient mitochondrial pool. This mechanism is distinct from antioxidants that simply neutralize free radicals; urolithin A acts more upstream, influencing the renewal process itself. A 2025 review summarizing the emerging sports nutrition evidence described this mitochondrial activation as the central rationale for investigating urolithin A in athletic populations [5].
Effects on Endurance Performance in Middle-Aged Adults
One of the more rigorous studies to date enrolled healthy middle-aged adults in a randomized, placebo-controlled trial testing urolithin A supplementation over four months. The pre-specified primary endpoint, peak power output on a cycling test, did not change significantly versus placebo. Peak VO2 rose within the 1,000 mg group but not significantly against placebo (p = 0.058), and plasma acylcarnitines fell at 500 mg but not at 1,000 mg [1].
Research note: In the urolithin A trial in 20 academy soccer players, the authors say the confidence limits on the primary and secondary findings were broad, and call for larger, well-powered confirmatory trials [4].
Hamstring strength, a secondary endpoint, rose 12% and 9.8% in the two dose groups, but the placebo group fell by 9.8%, so these are changes from baseline rather than a clean gain over placebo (p = 0.027 and p = 0.029) [1]. Notably, participants did not follow a structured exercise program during the study, suggesting these effects were not simply the result of increased training volume. Researchers interpreted the findings as a signal that urolithin A may support mitochondrial health in sedentary or lightly active middle-aged adults, but the trial was sponsored by Amazentis SA, the maker of Mitopure, and missed its primary endpoint [1]though it is not clear whether the magnitude of benefit would be similar in people who already train regularly [1].
Evidence in Trained Athletes: Distance Runners
Studies in middle-aged non-athletes raise a separate question: does urolithin A offer anything to people whose mitochondria are already being stressed and adapted through regular training? A 2025 randomized trial addressed this directly by recruiting highly trained male distance runners and measuring the effects of urolithin A supplementation on running performance, recovery markers, and mitochondrial biomarkers [2].
The 3,000 m time trial was not significantly improved in either group, and aerobic capacity did not differ significantly from placebo (interaction p = 0.138). Urolithin A did lower perceived exertion (p = 0.02) and creatine kinase after the time trial, and the authors concluded it did not further enhance performance in highly trained endurance athletes [2]. This pattern is not unusual in sports nutrition research: athletes who already train at high volumes have already driven substantial mitochondrial adaptation through exercise itself, which may leave less room for a supplement to produce an additional measurable effect. The authors noted that longer supplementation periods or different dosing strategies might be needed before conclusions can be drawn for elite endurance athletes [2].
Worth knowing: the distance-runner trial was supported by research funding from Amazentis SA, which also sponsored the middle-aged trial. The 20-athlete resistance-training trial was independently funded, and its authors reported no adverse events [2][1][3].
Muscle Endurance, Strength, and Recovery in Resistance-Trained Athletes
A 2024 double-blind, placebo-controlled trial examined urolithin A’s effects specifically in male athletes engaged in resistance training over eight weeks. The study measured muscle endurance, maximal strength, markers of inflammation, oxidative stress, and protein metabolism. Participants taking urolithin A improved on isometric force (p = 0.048) and repetitions to failure (p = 0.011) versus placebo, but 1RM bench press and squat gains were not significant, and the authors state the study did not show improved muscle strength [3].
In 20 male athletes, 8 weeks of urolithin A raised repetitions to failure but did not show a strength gain
20 resistance-trained men
1 g of urolithin A or placebo daily for 8 weeks, randomized and double-blind.
Isometric force and reps to failure
Maximum voluntary isometric contraction +43.50 N-m (p = 0.048) and repetitions to failure +2.00 (p = 0.011).
1RM bench press and squat
Gains of +3.50 kg and +2.55 kg did not reach significance (p = 0.462 and p = 0.710).
CRP rose in the treated group
C-reactive protein rose by 0.71 mg/L from baseline within the urolithin A group (p = 0.001).
Strength not shown to improve
No adverse events were reported, and the authors state the study did not show improved muscle strength.
A very small trial with a muscle endurance signal, no strength gain and no recovery benefit shown.
Randomized, double-blind, placebo-controlled trial in resistance-trained male athletes in China; effects are versus placebo unless stated. Source: Zhao et al., Journal of the International Society of Sports Nutrition 2024.
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C-reactive protein, an inflammation marker, rose by 0.71 mg/L from baseline within the urolithin A group (p = 0.001), and the researchers were careful to note that [3] the sample size was limited and that these findings should be considered preliminary. The eight-week window may not be sufficient to capture the full scope of adaptations that mitophagy-driven mitochondrial renewal could theoretically produce, particularly for strength outcomes that typically require longer training cycles to manifest [3].
Antioxidant Status and Team Sport Applications
A 2025 pilot randomized controlled trial tested urolithin A in academy soccer players during a preseason training block: a period characterized by high training loads and elevated oxidative stress. The Yo-Yo endurance test, the primary outcome, improved 239 m more on urolithin A than placebo (95% CI 20 to 454 m, p = 0.048), a wide interval from a 20-player single-blind trial. There were no group-by-time differences in sprint speed, jump power or saliva antioxidant assays [4].
The pilot design means these findings are exploratory rather than definitive, and the small sample limits how confidently results can be generalized. Still, the preseason context is interesting because it represents a scenario where training-induced oxidative stress and incomplete recovery are common challenges. The authors suggested that urolithin A’s apparent support for antioxidant defenses might be particularly relevant during high-load training phases, warranting larger confirmatory trials [4].
Where the Evidence Currently Stands
A 2025 narrative review of urolithin A in sports nutrition drew together findings from both preclinical and clinical studies, noting that the compound’s mechanistic rationale (mitophagy activation, mitochondrial renewal, downstream effects on muscle energy metabolism) is well-supported at the cellular level [5]. The translational picture for athletes, however, is still forming. Most human trials involve relatively small samples, short durations, and heterogeneous populations, making it difficult to draw firm conclusions about the size of any benefit or which athletes are most likely to respond.
It is also worth noting that not all people produce urolithin A from dietary sources at comparable rates. Gut microbiome composition influences how efficiently ellagitannin precursors are converted, which means baseline urolithin A status likely varies considerably among individuals: a factor that could affect supplement responsiveness but that most trials have not measured or stratified by [5]. Separately, research into related autophagy-activating pathways in skeletal muscle aging suggests that the mitophagy mechanism may be especially relevant as muscle quality declines with age, reinforcing the case for studying this compound across different age groups [6].
🛒 Where to Buy Urolithin A
- Timeline Mitopure SoftgelsClinically studied
softgels, 500 mg/day: The clinically studied form (Amazentis); used in the human trials. - Pure Encapsulations Renual
caplique capsules, 250 mg Mitopure Urolithin A/serving (with resveratrol + CoQ10): adds resveratrol and CoQ10, a combination the published urolithin A trials did not test. - ProHealth Longevity Urolithin A
capsules, 500 mg: Longevity-focused brand, often higher dose. - Double Wood Urolithin A
capsules, 250-500 mg: Budget-friendly, widely available, COA on request.
As an Amazon Associate we earn from qualifying purchases. Prices and availability vary; verify dose and third-party testing before buying.
A Note on the Evidence
The human evidence base for urolithin A and exercise performance is still early: most trials are small, short, and not yet independently replicated at scale, so it is too soon to make strong claims about the size or consistency of any benefit. This article is for informational purposes only and does not constitute medical advice; anyone with a health condition, those taking medications, or those considering supplementation during pregnancy or competitive sport should consult a qualified healthcare professional before starting.
Frequently Asked Questions
How does urolithin A actually affect muscles at the cellular level?
Urolithin A stimulates mitophagy, the process by which cells identify and break down dysfunctional mitochondria so they can be replaced by healthier ones. Because mitochondria generate the energy that powers muscle contractions, maintaining a high-quality mitochondrial pool is important for sustained performance. A 2025 review described this mitochondrial activation as the central rationale for investigating urolithin A in athletic populations [5].
Has urolithin A been shown to improve exercise performance in humans?
The most-cited human evidence is a company-funded randomized trial in middle-aged adults that missed its primary endpoint; secondary measures such as hamstring strength favoured urolithin A after four months [1]. Results in trained athletes have been more modest and less consistent, suggesting that effects may vary by baseline fitness level and training status [2].
Does urolithin A help with recovery after training?
Some evidence suggests it may. In an 8-week resistance training trial, C-reactive protein rose within the urolithin A group [3], and a soccer pilot found no group-by-time differences in saliva antioxidant assays [4]. In highly trained runners, urolithin A lowered perceived exertion and creatine kinase after a time trial [2]. All three studies were small and preliminary [3][4][2].
Do you need to supplement, or can you get enough from food?
Urolithin A is not present in food directly: it is produced by gut bacteria that metabolize ellagitannins from foods like pomegranates and walnuts. Conversion efficiency varies considerably between individuals based on microbiome composition, meaning that dietary intake does not reliably translate into meaningful urolithin A levels for everyone. This variability is part of why supplements have been studied as a more direct delivery method [5].
Is urolithin A only relevant for older adults?
Early research focused on older adults because mitophagy slows with age and mitochondrial quality is a key factor in age-related muscle decline. However, more recent trials have enrolled younger trained athletes, including distance runners and soccer academy players, exploring whether the compound offers anything to people who already exercise regularly [2][4]. Evidence in younger athletic populations is still limited.
What doses have been used in the research?
Clinical trials have generally used doses in the range of 500 mg to 1000 mg per day, though protocols differ across studies. The 2022 randomized trial in middle-aged adults tested 500 mg and 1,000 mg daily for four months and missed its primary endpoint [1]. Most trials have been too short and too small to establish an optimal dose with confidence, and dosing guidance for athletic populations specifically remains an open question [5].
References
- 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). PMID 35584623
- 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 (Auckland, N.Z.) (2025). PMID 40839339
- Zhao H et al. Assessment of Urolithin A effects on muscle endurance, strength, inflammation, oxidative stress, and protein metabolism in male athletes with resistance training: an 8-week randomized, double-blind, placebo-controlled study. Journal of the International Society of Sports Nutrition (2024). PMID 39487653
- Monsalve Acevedo A et al. Effects of Urolithin A supplementation on performance and antioxidant status in academy soccer players during preseason: a pilot randomised controlled trial. Frontiers in nutrition (2025). PMID 41245402
- Wang M et al. Emerging evidence of Urolithin A in sports nutrition: bridging preclinical findings to athletic applications. Frontiers in nutrition (2025). PMID 40453722
- Park SH et al. A Natural Autophagy Activator Castanea crenata Flower Alleviates Skeletal Muscle Ageing. Journal of cachexia, sarcopenia and muscle (2025). PMID 39873130
These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure, or prevent any disease. Content is for informational purposes only and is not medical advice; consult a qualified healthcare provider before starting any supplement. As an Amazon Associate we earn from qualifying purchases.