Urolithin A for Muscle: Strength, Endurance & Recovery

Of everything studied about urolithin A, its effect on skeletal muscle rests on the strongest human evidence. This is a look at what the muscle trials actually measured, the mitochondrial mechanism underneath, who is most likely to notice a difference, and what realistic expectations look like.

Why muscle is the best-studied outcome for urolithin A

Skeletal muscle is unusually dependent on mitochondria. Each contraction is paid for in ATP, the cell's energy currency, and muscle fibers are packed with mitochondria to keep that supply flowing. As we age, or after long periods of low activity, mitochondrial quality tends to decline: worn units accumulate, the cell's ability to recycle them slows, and muscle output and stamina can suffer. That makes muscle a natural place to look for a compound whose entire proposed mechanism is mitochondrial housekeeping.

Urolithin A is a gut postbiotic. It is not present in food directly. Instead, your gut microbiome produces it from ellagitannins, compounds found in pomegranate, walnuts, and certain berries. Only some people carry the microbial species needed to make meaningful amounts, which is one reason a consistent, standardized dose is useful rather than relying on diet alone. Once produced, urolithin A supports mitophagy, the process by which cells identify and recycle worn-out mitochondria so healthier ones can take their place.

The human evidence, organized by strength

Muscle strength and exercise performance (human)

The most directly relevant strength data comes from Singh and colleagues, published in Cell Reports Medicine in 2022. In middle-aged adults taking either 500 mg or 1,000 mg per day over four months, the trial reported improvements in measures of muscle strength and exercise performance. Both dose arms were examined, which is part of why the clinically studied range is described as 500 to 1,000 mg per day, with 1,000 mg sitting at the top of that range.

Muscle endurance (human)

A separate randomized trial by Liu, D'Amico and colleagues, published in JAMA Network Open in 2022, studied older adults over roughly four months. Here the standout finding was muscle endurance, specifically the number of muscle contractions participants could perform before reaching fatigue. Endurance and strength are different qualities, and it is meaningful that urolithin A has been associated with movement on both in separate human populations.

Newer human work in trained and athletic populations

Two more recent human trials extend the picture beyond older and middle-aged adults. An 8-week randomized controlled trial in resistance-trained men, published in the Journal of the International Society of Sports Nutrition in 2024, looked at endurance and recovery markers in people who were already training hard. And a 2025 trial in distance runners examined performance-related outcomes in a competitive endurance population. These are smaller and newer than the foundational strength and endurance studies, but they suggest interest in urolithin A is not limited to sedentary or aging groups.

The foundational science (preclinical, not human proof)

The original demonstration that urolithin A drives mitophagy came from Ryu and colleagues in Nature Medicine in 2016. That work, conducted in the roundworm C. elegans and in rodents, showed improved mitochondrial recycling, extended lifespan in the worm model, and improved muscle function in animals. This is important mechanistic groundwork, but it is animal and cell research. It explains why researchers expected muscle benefits in people; it does not, on its own, prove them. The human trials above are what carry that weight.

How the mechanism connects to what you feel

It helps to separate two ideas. A stimulant like caffeine changes how alert you feel within an hour by acting on the nervous system. Urolithin A does something structurally different and slower: it supports the cellular machinery that produces energy in the first place. By promoting mitophagy, it helps clear damaged mitochondria so the remaining population is, on average, healthier and more efficient. In muscle, a healthier mitochondrial pool is what underlies sustained output, the ability to keep contracting without fatiguing as quickly.

Because this is a housekeeping process rather than a stimulant effect, it is foundational and gradual. The human muscle trials ran for roughly four months, not four days. That timeline is a realistic anchor: this is something taken consistently to support an underlying system, not a pre-workout you feel acutely.

Who is most likely to notice a difference

Based on the populations actually studied, the people with the most relevant data are middle-aged and older adults, and more recently trained athletes. Several factors make someone a reasonable candidate: being past their thirties, having gone through a stretch of reduced activity, or simply not being an efficient natural producer of urolithin A from diet. Because conversion from dietary ellagitannins varies so widely between individuals, a standardized supplemental dose removes that variability. To go deeper on the underlying biology, see our guide to mitophagy and our overview of mitochondrial health.

Honest limitations

The muscle evidence is genuinely among the strongest in this field, but it should be read with care. A 2024 systematic review in Ageing Research Reviews, examining urolithin A for aging in humans, concluded that the evidence is still emerging: trials so far have been relatively short and modest in size. Effects reported in the strength and endurance studies were measurable but not dramatic, and results can vary between individuals. Urolithin A supports muscle and mitochondrial function; it is not a substitute for the two things with the deepest evidence base for muscle, which are resistance training and adequate protein. It works best alongside them, not instead of them. If you have a muscle-related medical condition or unexplained weakness, this is not a treatment for that condition, and you should see your doctor.

Practical guidance

The studied daily amount is 500 to 1,000 mg. SOMA HEALTH Urolithin A Gummies are formulated at 1,000 mg per 4-gummy serving, the upper end of that range. Take it consistently every day, pair it with your training and protein intake, and judge it over months rather than days. For more on timing and routine, see how to take urolithin A and how long it takes to work. For the full picture, read our complete urolithin A guide, and to compare products, our roundup of the best urolithin A gummies.

*These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease. This guide is educational and is not a substitute for advice from a qualified healthcare provider.