September 29, 2026
Urolithin A is a compound made by gut bacteria from polyphenols in pomegranates, berries and walnuts. It switches on mitophagy, the process cells use to recycle damaged mitochondria. Human trials link it to better muscle endurance and strength in middle-aged and older adults, which is why it is one of the few longevity ingredients with solid clinical data.
Key facts
- Mitochondria produce most of your cellular energy, and their quality declines with age.
- Urolithin A extended lifespan in worms and improved muscle function in aged mice (Ryu et al., Nature Medicine, 2016).
- Randomized human trials used 500-1,000 mg daily for up to four months.
- Only a minority of people make meaningful urolithin A from food, because it depends on specific gut bacteria.
What is urolithin A?
Foods like pomegranate, raspberries, strawberries and walnuts contain ellagitannins and ellagic acid. When you eat them, certain gut microbes convert these compounds into urolithins. Urolithin A is the most studied.
The catch is that conversion varies enormously.
Many people lack the right bacteria and produce little or none, no matter how much pomegranate they eat. Researchers estimate only around 40% of people are strong producers.
Taking urolithin A directly bypasses that step.
How does urolithin A work? Mitophagy explained
Each cell contains hundreds of mitochondria. Over time some become damaged.
They produce less energy and leak reactive oxygen species. Healthy cells tag these broken mitochondria and digest them, a process called mitophagy. New mitochondria replace them.
Mitophagy slows with age. Damaged mitochondria accumulate, especially in muscle, which is one reason energy and endurance decline.
Urolithin A activates the mitophagy machinery, helping cells clear old mitochondria and maintain a healthier population.
Mitophagy is one branch of autophagy, the cell’s wider recycling system. Spermidine is another compound studied for autophagy, mostly in yeast, worms, flies and mice; our guide to the spermidine evidence explains where that evidence stops.
What does the research show?
In animals. In 2016, Dongryeol Ryu, Johan Auwerx and colleagues at EPFL published in Nature Medicine that urolithin A extended the lifespan of C. elegans worms and improved exercise capacity in aged mice. It induced mitophagy in both.
First human study. In 2019, Pénélope Andreux and colleagues reported the first human trial in Nature Metabolism. Sixty older adults took 250, 500 or 1,000 mg for four weeks. Urolithin A was safe and well tolerated. At 500 and 1,000 mg it increased the expression of mitochondrial genes in muscle and improved markers of mitochondrial function in the blood.
Muscle endurance in older adults. A 2022 randomized trial by Sophia Liu and colleagues in JAMA Network Open gave 66 adults aged 65-90 either 1,000 mg or placebo for four months. The urolithin A group improved endurance in a hand muscle and showed lower blood levels of acylcarnitines, a marker of poor mitochondrial fuel use. Walking distance did not differ significantly from placebo.
Muscle strength in middle age. Also in 2022, Anurag Singh and colleagues published a trial of 88 adults aged 40-65 in Cell Reports Medicine. Over four months, 500 and 1,000 mg doses improved leg muscle strength by roughly 12% compared with placebo, along with some measures of exercise performance.
Immune aging. Newer research is exploring whether urolithin A supports immune cells, which also depend on healthy mitochondria. Early human results suggest effects on T-cell populations (Denk et al., Nature Aging, 2025).
How much urolithin A should you take?
The functional benefits in human trials came at 500-1,000 mg per day. The 250 mg dose was tested for safety in the 2019 study and was well tolerated, but it did not produce the same mitochondrial gene changes as the higher doses.
Ares contains 500 mg as part of a six-ingredient formula designed to support several aging pathways together rather than maximize any single one. That dose sits at the low end of the 500-1,000 mg range that showed effects in human trials. It is the lower of the two doses that increased mitochondrial gene expression in the 2019 study and improved leg strength in the 2022 trial in middle-aged adults, and half the 1,000 mg used in the trial of adults aged 65-90. We want you to know how that compares with the trials so you can decide what's right for you.
Is urolithin A safe?
In human studies up to 1,000 mg daily for four months, urolithin A was well tolerated, with side effects similar to placebo. It has a GRAS notification with the FDA for use in foods. Long-term data beyond several months is limited. Pregnant or nursing women and anyone on medication should talk to a doctor first.
The bottom line
Urolithin A has one of the stronger evidence bases among longevity ingredients: a clear mechanism, animal lifespan data, and multiple randomized human trials showing effects on muscle. See how it fits with the other five ingredients in My Longevity Stack, or compare it with other options in Longevity Supplements That Actually Have Human Data.
FAQ
Can I get urolithin A from pomegranate juice? Only if your gut bacteria can convert it. Many people produce little urolithin A from food, which is why direct supplementation is used in trials.
How long does urolithin A take to work? Human trials measured changes after four weeks for mitochondrial markers and around four months for muscle strength and endurance.
What is mitophagy? Mitophagy is how cells find and recycle damaged mitochondria. It declines with age, and urolithin A helps activate it.
Is urolithin A the same as ellagic acid? No. Ellagic acid is the dietary precursor. Gut bacteria convert it into urolithin A, the compound that reaches your tissues.
Published by the SciRouter Editorial Team for general educational purposes. Last updated September 2026.
Educational disclaimer. This article is for educational and informational purposes only and is not medical advice. It summarizes published scientific research and does not endorse any specific product, supplement, drug, or treatment. These statements have not been evaluated by the Food and Drug Administration, and any products mentioned are not intended to diagnose, treat, cure, or prevent any disease. Always consult a licensed physician before starting, stopping, or changing any supplement or medication, especially if you are pregnant, nursing, have a medical condition, or take prescription medication.
