Best Urolithin A for Endurance & Stamina

Reviewed by SOMA HEALTH's Medical Research Team

Endurance is, at its root, a cellular question: how well your working muscles keep producing energy when the demand does not stop. Urolithin A is a gut-derived postbiotic being studied for its role in supporting mitochondrial quality, the very machinery that powers sustained aerobic effort. This guide explains what the human research actually shows, where the evidence is still preclinical, and how a runner or cyclist might think about it, all in structure/function terms.

Why endurance begins in the mitochondria

Every stride, pedal stroke, and sustained push is paid for in ATP, the chemical energy currency your cells spend to contract muscle. The overwhelming majority of that ATP is produced inside mitochondria through oxidative phosphorylation, a process that uses oxygen to extract energy from fats and carbohydrates. This is why endurance physiology is so tightly linked to mitochondria: trained endurance athletes characteristically carry a higher density of mitochondria and greater oxidative capacity in their muscle fibers than untrained people, and maximal oxygen uptake tracks closely with muscle oxidative capacity. When those mitochondria are plentiful and working efficiently, a muscle can keep resynthesizing ATP aerobically for longer before fatigue forces a slowdown.

Over time and under repeated stress, individual mitochondria wear out. Damaged mitochondria become less efficient and can leak reactive byproducts. The body's housekeeping answer is mitophagy, a targeted form of cellular recycling that identifies worn-out mitochondria and clears them so healthier ones can take their place. Supporting that quality-control process is the biological rationale behind urolithin A.

What urolithin A is, and how it works

Urolithin A is not something most foods contain directly. It is a postbiotic: your gut microbiome produces it from ellagitannins, the polyphenols found in pomegranate, walnuts, and certain berries. Here is the catch that makes a supplement interesting. Only some people carry the gut bacteria needed to convert ellagitannins into meaningful amounts of urolithin A, so eating pomegranate is no guarantee your body actually makes it. A defined dose bypasses that lottery.

Mechanistically, urolithin A has been studied as a compound that supports mitophagy, the recycling of worn mitochondria described above. The working idea is that by helping clear damaged mitochondria, the cell can maintain a healthier, more efficient mitochondrial pool, which is exactly the quality that endurance depends on.

The human evidence, strongest first

The first-in-human work, Andreux and colleagues in Nature Metabolism (2019, HUMAN), established that urolithin A was safe and well tolerated at doses up to 1,000 mg per day and, importantly, that it produced a measurable mitochondrial gene-expression signature in people. That study is about safety and biological plausibility rather than race times, but it is the foundation everything else builds on.

For performance specifically, Singh and colleagues in Cell Reports Medicine (2022, HUMAN) tested 500 mg and 1,000 mg daily in middle-aged adults over four months and reported effects on muscle strength and exercise performance. Liu, D'Amico and colleagues in JAMA Network Open (2022, HUMAN) ran a roughly four-month trial in older adults and observed improvements in muscle endurance, a measure that sits very close to what a stamina-focused athlete cares about. More recently, an eight-week randomized controlled trial in resistance-trained men, published in the Journal of the International Society of Sports Nutrition (2024, HUMAN), examined urolithin A in an already-trained population, and a 2025 trial in distance runners (HUMAN) extended this line of research into an explicitly endurance-oriented group.

Newer human signals

A 2025 randomized controlled trial in Nature Aging (HUMAN, roughly 28 days) reported that urolithin A supported the mitochondrial health of immune cells in midlife adults, part of the emerging conversation around age-related low-grade inflammation. This is relevant to endurance indirectly: recovery and sustained training capacity are shaped by more than muscle alone. Still, a 2024 systematic review in Ageing Research Reviews is candid that the human evidence base, while growing and encouraging, is still emerging. Trials vary in size, duration, and population, and no one should expect a single supplement to substitute for the base-building miles that actually drive endurance adaptation.

The preclinical foundation (label this clearly)

Much of the early excitement came from animal and cell work that should be read as mechanism, not proof of human benefit. Ryu and colleagues in Nature Medicine (2016, PRECLINICAL) showed that urolithin A induced mitophagy, extended lifespan in the roundworm C. elegans, and improved muscle function in rodents. Separately, D'Amico and colleagues in Aging Cell (2022, PRECLINICAL) explored joint and cartilage outcomes in osteoarthritis models, which is of passing interest to endurance athletes who care about durable joints, but again, those results are preclinical. Treat them as the reason researchers ran the human trials, not as a promise about your next long run.

How endurance athletes think about using it

The human trials have used 500 to 1,000 mg per day, with 1,000 mg representing the top of the studied range. SOMA HEALTH Urolithin A Gummies deliver 1,000 mg per four-gummy daily serving, which matches that upper studied dose in a raspberry, sugar-free, third-party-tested format. Because urolithin A works by supporting a slow biological housekeeping process rather than by acute stimulation, consistency matters more than timing. It is not a pre-workout; you take it daily and let it accumulate. For a realistic sense of the runway involved, see our note on how long urolithin A takes to work, and for the mechanism itself, our explainer on what mitophagy is.

Honest limitations

Urolithin A is not a stimulant and will not make a hard effort feel easier the way caffeine can. It does not replace training, sleep, or fueling, and the human endurance-performance literature is still young. If persistent fatigue, breathlessness, or a genuine drop in exercise tolerance is your concern, that is a matter for a qualified healthcare provider, not a supplement decision: this product is intended to support normal cellular and mitochondrial function, not to treat any medical condition. For the wider picture, our urolithin A guide and roundup of the best urolithin A gummies put this endurance angle in context.

*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.