Partly. Urolithin A is a compound your gut bacteria make from foods like pomegranates and walnuts, and it switches on mitophagy, the cell's system for recycling worn-out mitochondria (the power plants inside your cells). In small human trials it improved signs of mitochondrial health, muscle endurance and leg strength. But in both main muscle trials, the result the researchers were primarily testing, walking distance in one and power output in the other, did not improve more than with a dummy pill. All of these trials were funded by the company that sells it. Promising, not proven.
- SymptomMuscles tire faster and recover slower with age
- Before thatMuscle cells produce less usable energy
- Before thatWorn-out mitochondria pile up inside them
- Before thatThe cell's recycling system for mitochondria slows down
- RootMitophagy declines with age
What urolithin A actually is
Pomegranates, walnuts, raspberries and strawberries contain plant compounds called ellagitannins. Your body can't use them directly. Instead, certain gut bacteria, the microbes living in your intestine, break them down into smaller molecules. One of those breakdown products is urolithin A.
So urolithin A isn't really in the fruit. It's made by your microbes from the fruit. That detail turns out to matter a lot.
Why anyone cares: the recycling problem
Your cells contain hundreds of mitochondria, the tiny power plants that turn food and oxygen into ATP, the energy molecule every cell runs on. Like any machine, mitochondria wear out. Healthy cells handle this with mitophagy, a recycling system that tags damaged mitochondria, breaks them down and reuses the parts. Think of it as a garbage truck that hauls away broken power plants so new ones can be built.
With age, that garbage truck comes less often. Worn-out mitochondria pile up, especially in muscle, and the cell makes less energy. Slower mitophagy is linked to two of the twelve hallmarks of aging, the main processes scientists agree drive aging. Our deep dive on what breaks inside mitochondria explains why this matters so much.
In 2016, researchers reported that urolithin A switches mitophagy back on. In tiny worms it extended lifespan, and in aging mice and in rats it improved exercise capacity.[1] That's animal evidence, grade C. The big question was whether anything similar happens in people.
What the human trials found
Before we look at results, one idea that most articles skip. Every good trial names its primary endpoint in advance: the single main result it's designed to test. Everything else is a secondary endpoint, interesting but less reliable, because the more things you measure, the more likely a few look good by chance. Keep that in mind.
Older adults, 4 weeks: safety and cell signals
A · Small trialIn the first human study, urolithin A was safe and well tolerated, and muscle samples showed a pattern of genes linked to healthier mitochondria. Blood markers of better mitochondrial fuel use also improved.[2] Encouraging, but these are biomarkers, measurable signals in the body, not changes people can feel.
Adults 65 to 90, 4 months: endurance up, walking not
A · 66 peopleThe primary endpoint, how far people could walk in six minutes, improved in both groups, and the difference between urolithin A and placebo (a dummy pill) wasn't statistically significant, meaning it could have been chance. But hand and leg muscles could contract more times before tiring, a secondary result that did beat placebo.[3]
Adults 40 to 64, 4 months: stronger legs, same power
A · 88 peopleThe primary endpoint, peak power on an exercise bike, didn't improve versus placebo. Neither did fitness or the six-minute walk. But leg muscle strength rose by roughly 10 to 12 percent, and blood markers of inflammation (the body's alarm-and-repair response, which drives aging when it never switches off) dropped, both secondary results.[4]
Adults 45 to 70, 4 weeks: immune cells
A · 50 people, shortThe newest trial looked at the immune system, the body's defense network against infections. People taking urolithin A had slightly more "fresh", ready-to-respond immune cells, the kind that usually dwindle with age.[5] Interesting, but it was short and measured cells in the blood, not fewer infections or better health.
Clinical trials prove urolithin A improves muscle and slows aging.
The trials missed their main goals but found real improvements in endurance, strength and cell markers. That's a promising signal, not proof. And no trial has tested aging itself.
Three things to know before you buy
1. Who paid
All of the human trials above were funded by Amazentis, the company that developed and sells the urolithin A supplement Mitopure.[3][4] That's normal for a new ingredient, and it doesn't mean the results are wrong. It does mean we'd like to see independent trials before calling anything settled.
2. Your gut decides if food works
Because your microbes do the converting, people differ enormously. In one study, only about 40 percent of people made meaningful urolithin A after drinking pomegranate juice.[6] The rest made little or none. That's why researchers moved to giving urolithin A directly as a supplement, which bypasses the gut lottery.
3. Small and short
The biggest trial had 88 people, and none lasted more than four months. That's enough to spot a signal, not enough to know about long-term benefits or risks.
How it compares to other ways to restart mitophagy
Exercise
A · StrongestTraining is the most powerful natural signal for both clearing old mitochondria and building new ones, and it improves the things urolithin A trials struggled to move, like fitness and walking. Start with our guide to why you're tired after 40.
Urolithin A
A · Small, mixedReal effects on endurance, strength and cell markers in small, industry-funded trials; main goals missed. Possibly most interesting for people who can't exercise much, but that hasn't been tested.
Fasting
C · Mostly animalLow energy activates the cell's fuel gauge, which flags damaged mitochondria for recycling. Clear in animals and cells; direct human evidence for mitophagy is thin.
Eating pomegranates and walnuts
B · Depends on your gutHealthy foods either way. Whether they give you urolithin A depends on whether your gut bacteria can make it.
The bottom line
Urolithin A is one of the more scientifically interesting longevity supplements, because it targets a real, upstream problem, the cell's slowing recycling system, and has actual human trials behind it. But those trials are small, short, industry-funded, and missed their main goals. The honest summary: a real signal worth watching, not a replacement for training. If you exercise regularly, you're already switching on the same recycling system, for free.
Frequently asked questions
Can I get urolithin A from pomegranate juice?
Only if your gut bacteria can make it. In one study, only about 40% of people produced meaningful amounts after drinking pomegranate juice. Pomegranates, walnuts, raspberries and strawberries contain the raw materials, but your microbes do the conversion.
How much urolithin A was used in studies?
Human trials used 500 mg or 1,000 mg per day, usually for 4 weeks to 4 months. Benefits on muscle were measured after 2 to 4 months.
Is urolithin A safe?
In trials lasting up to 4 months, it was well tolerated, with side effects similar to placebo. Long-term safety data beyond that are limited. If you take medication or have a medical condition, talk to your doctor first.
Is urolithin A better than exercise?
No. Exercise is a powerful natural trigger for mitophagy and has far stronger evidence for energy, muscle and longevity. Urolithin A is at best a supporting act, and might be most interesting for people who can't exercise much, though that idea hasn't been properly tested yet.
Who funded the urolithin A studies?
The main human trials were funded by Amazentis, the company that developed and sells the urolithin A supplement Mitopure. Industry funding doesn't make results wrong, but it's a reason to want independent confirmation.
Sources
- Ryu D, et al. Urolithin A induces mitophagy and prolongs lifespan in C. elegans and increases muscle function in rodents. Nature Medicine, 2016.
- Andreux PA, et al. The mitophagy activator urolithin A is safe and induces a molecular signature of improved mitochondrial and cellular health in humans. Nature Metabolism, 2019.
- Liu S, et al. Effect of urolithin A supplementation on muscle endurance and mitochondrial health in older adults: a randomized clinical trial. JAMA Network Open, 2022.
- 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.
- Denk D, et al. Effect of the mitophagy inducer urolithin A on age-related immune decline: a randomized, placebo-controlled trial. Nature Aging, 2025.
- Singh A, et al. Direct supplementation with urolithin A overcomes limitations of dietary exposure and gut microbiome variability in healthy adults to achieve consistent levels across the population. European Journal of Clinical Nutrition, 2022.