What it means
Urolithin A is not found in food. It is made by gut bacteria from ellagitannins in pomegranate, walnuts and berries — and only about 40% of people have the bacteria to make it in useful amounts. It induces mitophagy, the mitochondria-specific branch of autophagy, clearing damaged mitochondria so that new ones can be made.
It is sold as a direct supplement (500–1,000 mg per day) under the Mitopure trade name and in generics, which bypasses the microbiome variability.
Why it matters for longevity
Mitochondrial quality declines with age and is the proximate cause of much of the fall in endurance and muscle function. A compound that restores mitophagy, if it worked in people, would address that directly. Urolithin A is the candidate that has gone furthest through proper trials.
What the evidence says
Ryu 2016 (Nature Medicine): urolithin A extended lifespan in worms by 45% and improved muscle function in old mice. Andreux 2019: first human trial, 60 older adults, four weeks, safe, improved mitochondrial gene expression in muscle.
Liu 2022 (JAMA Network Open): 66 adults aged 65–90, 1,000 mg/day for four months, placebo-controlled; improved hand-grip and leg-muscle endurance (number of contractions before fatigue) by about 10–15%, no change in six-minute walk or VO2max. Singh 2022: 88 middle-aged adults, 500–1,000 mg for four months; improved leg endurance and peak power, lower hs-CRP, no change in VO2max. Nothing on lifespan or disease outcomes.
How to measure or use it
- Whether you make it naturally can be tested (urine urolithin A after pomegranate), but direct supplementation sidesteps the question.
- The endpoints the trials used — muscle endurance to fatigue, grip, hs-CRP — are the fair ones to judge it on, over four months.
- Training does the same job with a larger effect: twelve weeks of intervals raised mitochondrial capacity by 69% in older adults (Robinson 2017).
Related
- Mitochondria and energy — the training comparison
- Supplements that have evidence — where it ranks
- Muscle mass and ageing — muscle endurance in context
Frequently asked questions
Can I get urolithin A from pomegranate?
Only if your gut bacteria convert ellagitannins to it; roughly 40% of people do so efficiently. A supplement bypasses that.
How big is the effect?
About 10–15% more muscle-endurance contractions before fatigue over four months, with no change in VO2max or walking distance.
Is it safe?
Four-month trials at 1,000 mg/day found no safety signal. Long-term data do not exist.
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