EvidenceCLimitedStudies in people with real weaknesses: small, short or conflicting trials, or observational studies only.
Urolithin A may add a little muscle strength and endurance in middle-aged and older adults. Walking distance and peak power didn't clearly improve, and we don't know yet whether it matters in daily life.
Who it's for
Middle-aged and older adults wanting more muscle endurance; no group has a clear benefit.
What to expect
About 12% more leg strength in one 4-month trial; walking gains unclear.
Watch out for
Nothing notable reported; trials were small and short.
Urolithin A may add walking distance, but results are uncertain
A dot with a line shows the extra distance walked in 6 minutes on urolithin A versus placebo, and the line shows the range that could include no effect.
← WorseBetter →
No difference
Pooled result, both doses combined17.03 (−5.33 to 39.4)No clear difference
Pooled result, placebo split18.8 (−3.24 to 40.85)No clear difference
02040
metres in 6-minute walk, vs. placebo
Urolithin A may add walking distance, but results are uncertain
A review of five small randomized trials People are assigned by chance to the treatment or a comparison, so a difference in results is likely caused by the treatment itself. (236 people) found the strength, endurance and blood-marker results varied too much to combine. The authors call them early signals, not proven effects4Systematic review · 2026 · 236 peopleEffects of Urolithin A supplementation on muscle health outcomes in humans from randomized controlled trials.The currently available randomized human evidence is limited to five small, short-term trials in clinically heterogeneous populations. Quantitative pooling was feasible for a single outcome (6MWT) based on two trials and showed a directionally favorable but statistically inconclusive effect with low GRADE certainty.…Front Nutr.
Only the 6-minute walk could be pooled, from two trials. Urolithin A groups walked about 17 metres farther than placebo A dummy treatment that looks like the real one, so people can't tell which they got. groups. The true effect could be anything from a small loss to about 39 metres of gain, so chance can't be ruled out4Systematic review · 2026 · 236 peopleEffects of Urolithin A supplementation on muscle health outcomes in humans from randomized controlled trials.The currently available randomized human evidence is limited to five small, short-term trials in clinically heterogeneous populations. Quantitative pooling was feasible for a single outcome (6MWT) based on two trials and showed a directionally favorable but statistically inconclusive effect with low GRADE certainty.…Front Nutr.
A 4-month trial in middle-aged adults tested two doses against a dummy pill (placebo). Leg strength rose about 12% on urolithin A. Peak power, the main goal of the trial, didn't improve significantly1Randomized trial · 2022Urolithin A improves muscle strength, exercise performance, and biomarkers of mitochondrial health in a randomized trial in middle-aged adults.We also examine expression of proteins linked to mitophagy and mitochondrial metabolism in skeletal muscle and find a significant increase with Urolithin A administration. This study highlights the benefit of Urolithin A to improve muscle performance.Cell Rep Med.
Walking and aerobic fitness were described as meaningfully better in that trial, and blood markers of inflammation were lower1Randomized trial · 2022Urolithin A improves muscle strength, exercise performance, and biomarkers of mitochondrial health in a randomized trial in middle-aged adults.We also examine expression of proteins linked to mitophagy and mitochondrial metabolism in skeletal muscle and find a significant increase with Urolithin A administration. This study highlights the benefit of Urolithin A to improve muscle performance.Cell Rep Med.
A trial of 66 adults aged 65 to 90 gave 1,000 mg a day for 4 months. Muscle endurance in a hand muscle and a leg muscle improved at 2 months compared with placebo. The 6-minute walk and muscle energy production did not differ significantly2Randomized trial · 2022 · 66 peopleEffect of Urolithin A Supplementation on Muscle Endurance and Mitochondrial Health in Older Adults: A Randomized Clinical Trial.This randomized clinical trial found that urolithin A supplementation was safe and well tolerated in the assessed population. Although the improvements in the 6-minute walk distance and maximal ATP production in the hand muscle were not significant in the urolithin A group vs the placebo group, long-term urolithin A…JAMA Netw Open.
In a trial of 20 trained men, 1 g a day for 8 weeks improved some endurance and force measures versus placebo. Bench press and squat gains were not significant6Randomized trial · 2024Assessment 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.After 8 weeks of UA supplementation at 1 g/day, resistance-trained male athletes showed improvements in muscle strength and endurance. Additionally, UA supplementation was also associated with reduced oxidative stress levels and a decrease in inflammation response levels.J Int Soc Sports Nutr.
A separate review of five studies in 250 healthy people found more strength and endurance, but no effect on physical function or heart measures3Systematic review · 2024 · 250 peopleTargeting aging with urolithin A in humans: A systematic review.Unrelated adverse events were mild or moderate. Further research across more physiological systems and longer intervention periods is required.Ageing Res Rev.
Reviews that describe clear benefit come largely from the same few trials5Review · 2021Impact of the Natural Compound Urolithin A on Health, Disease, and Aging.In humans, benefits of UA supplementation in the muscle are supported by recent clinical trials in elderly people. Here, we review the state of the art of UA's biology and its translational potential as a nutritional intervention in humans.Trends Mol Med,10Review · 2024Mitophagy Activation by Urolithin A to Target Muscle Aging.The natural postbiotic Urolithin A has been shown to promote mitophagy, mitochondrial function and improved muscle function across species in different experimental models and across multiple clinical studies. In this review, we explore the biology of Urolithin A and the clinical evidence of its impact on promoting…Calcif Tissue Int.
Key studies
Study
Who
What it found
Review of 5 trials, 20264Systematic review · 2026 · 236 peopleEffects of Urolithin A supplementation on muscle health outcomes in humans from randomized controlled trials.The currently available randomized human evidence is limited to five small, short-term trials in clinically heterogeneous populations. Quantitative pooling was feasible for a single outcome (6MWT) based on two trials and showed a directionally favorable but statistically inconclusive effect with low GRADE certainty.…Front Nutr
236 adults
Walk gain unclear; other results too varied to pool
Trial, 20221Randomized trial · 2022Urolithin A improves muscle strength, exercise performance, and biomarkers of mitochondrial health in a randomized trial in middle-aged adults.We also examine expression of proteins linked to mitophagy and mitochondrial metabolism in skeletal muscle and find a significant increase with Urolithin A administration. This study highlights the benefit of Urolithin A to improve muscle performance.Cell Rep Med
Middle-aged adults, 4 months
Leg strength up about 12%; peak power unchanged
Trial, 20222Randomized trial · 2022 · 66 peopleEffect of Urolithin A Supplementation on Muscle Endurance and Mitochondrial Health in Older Adults: A Randomized Clinical Trial.This randomized clinical trial found that urolithin A supplementation was safe and well tolerated in the assessed population. Although the improvements in the 6-minute walk distance and maximal ATP production in the hand muscle were not significant in the urolithin A group vs the placebo group, long-term urolithin A…JAMA Netw Open
66 adults aged 65 to 90
Better muscle endurance; walk distance not significantly better
Trial, 20246Randomized trial · 2024Assessment 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.After 8 weeks of UA supplementation at 1 g/day, resistance-trained male athletes showed improvements in muscle strength and endurance. Additionally, UA supplementation was also associated with reduced oxidative stress levels and a decrease in inflammation response levels.J Int Soc Sports Nutr
20 resistance-trained men
Some strength and endurance gains; lifts not significant
Safety
Trials of 28 days to 4 months reported mild or moderate side effects unrelated to the supplement3Systematic review · 2024 · 250 peopleTargeting aging with urolithin A in humans: A systematic review.Unrelated adverse events were mild or moderate. Further research across more physiological systems and longer intervention periods is required.Ageing Res Rev. In the older-adult trial, side effects did not differ from placebo2Randomized trial · 2022 · 66 peopleEffect of Urolithin A Supplementation on Muscle Endurance and Mitochondrial Health in Older Adults: A Randomized Clinical Trial.This randomized clinical trial found that urolithin A supplementation was safe and well tolerated in the assessed population. Although the improvements in the 6-minute walk distance and maximal ATP production in the hand muscle were not significant in the urolithin A group vs the placebo group, long-term urolithin A…JAMA Netw Open. Trials used 10 to 1,000 mg a day3Systematic review · 2024 · 250 peopleTargeting aging with urolithin A in humans: A systematic review.Unrelated adverse events were mild or moderate. Further research across more physiological systems and longer intervention periods is required.Ageing Res Rev. Long-term safety is untested.
What we don't know
Whether the gains last, or make people stronger in daily life, since trials were short and small.
Whether results hold in more diverse groups; the older-adult trial was mostly white women2Randomized trial · 2022 · 66 peopleEffect of Urolithin A Supplementation on Muscle Endurance and Mitochondrial Health in Older Adults: A Randomized Clinical Trial.This randomized clinical trial found that urolithin A supplementation was safe and well tolerated in the assessed population. Although the improvements in the 6-minute walk distance and maximal ATP production in the hand muscle were not significant in the urolithin A group vs the placebo group, long-term urolithin A…JAMA Netw Open.
Written by AI from the studies listed, without review by a clinician, and graded with the GRADE method. It can be wrong, so check the studies it cites. Education, not medical advice.