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Urolithin A

A compound the gut makes from substances in foods such as pomegranates, walnuts and raspberries. It has been studied for muscle, mitochondria and aging.

Explained simply · Last reviewed 2026-09-26

What it is

Urolithin A is a compound the gut makes from substances in some foods. According to a 2024 systematic review, plants such as pomegranate, walnut and raspberry are rich in substances called ellagitannins. These are broken down in the gut to ellagic acid and then to urolithins, of which urolithin A is one. A 2026 review of muscle trials describes urolithin A as a candidate for improving mitochondrial quality control and muscle function by activating mitophagy, the process by which cells clear out worn-out mitochondria, the parts of a cell that produce energy. It adds that the five small trials so far do not yet show that urolithin A meaningfully restores mitochondrial quality control in people.

More about Urolithin A

According to a 2024 systematic review, plants such as pomegranate, walnut and raspberry are rich in substances called ellagitannins. These are broken down in the gut to ellagic acid and then to urolithins, of which urolithin A is one. A 2026 review of muscle trials describes urolithin A as a candidate for improving mitochondrial quality control and muscle function by activating mitophagy, the process by which cells clear out worn-out mitochondria, the parts of a cell that produce energy. It adds that the five small trials so far do not yet show that urolithin A meaningfully restores mitochondrial quality control in people.

The 2024 review states that gut bacteria influence this conversion, and that the amount made varies between people and decreases with age. The 2026 review notes that this variation between people has motivated giving urolithin A directly as a supplement, to reach consistent levels in the body.

In 2018 the US Food and Drug Administration (FDA) responded to a notice from Amazentis, a company that makes urolithin A. According to the FDA's letter, the ingredient described in that notice is made by chemical synthesis.

The ratings below cover muscle, mitochondria, inflammation markers and lifespan.

At a glance

Safety: known risks and 3 groups who should avoid it or take extra care. See Safety ↓

Claims made about Urolithin A, and how strong the evidence is for each:

Improves muscle strength and enduranceEvidence rating: Limited
Improves the health of mitochondria, the energy-producing parts of cellsEvidence rating: Limited

Longevity and aging claims

Claims made about Urolithin A and aging, and how strong the evidence is for each. A change in a marker is not the same as a longer life.

Helps people live longerEvidence rating: Insufficient
Lowers blood markers of inflammationEvidence rating: Limited

Each rating follows our published rules and the sources cited for it. We don’t add our own medical judgment. How we rate

Safety

Read this before the ratings below.

Risks

A 2024 systematic review of five human studies in 250 healthy people, lasting from 28 days to 4 months, reports that "There were no serious adverse events attributed directly to UA reported in any of the studies". The adverse events seen, such as muscle aches and headaches, were mild to moderate and judged unrelated to urolithin A. None of the studies followed people up after they stopped taking it.
In a 4-month trial in 66 adults aged 65 to 90, adverse events did not differ significantly between urolithin A and placebo, no serious adverse events were reported, and there were no significant differences in vital signs, blood tests or urine tests. A 4-month trial in 88 middle-aged adults reported the same kind of safety tests with no significant differences from placebo. Both trials were funded by Amazentis, a company that makes urolithin A.
A 2026 systematic review of the trials notes that they lasted between 4 weeks and 4 months, so long-term safety cannot be inferred from them.
In 2018 the US Food and Drug Administration (FDA) responded to a notice from Amazentis, which concluded that its urolithin A is generally recognized as safe ("GRAS") as an ingredient in certain foods, such as protein shakes, nutrition bars and yogurts, at the levels the company described. FDA wrote that it had "no questions at this time" about that conclusion, and that its letter "is not an affirmation" that urolithin A is GRAS. The safety conclusion is the company's, and it covers use in those foods; the letter does not address supplements.

Who should avoid it or take extra care

People taking regular medicines: the 4-month trial in middle-aged adults excluded "those with chronic diseases that required medications (statins, blood thinners, steroid and thyroid medications)", and the 4-month trial in adults aged 65 to 90 required participants to be healthy. The 2024 systematic review states that concurrent drug use may lead to interactions with urolithin A that warrant "further exploration".
The examples of possible drug interactions that the 2024 systematic review gives come from laboratory studies, not people. In prostate cancer cells, the prostate cancer drug bicalutamide reduced one of urolithin A's effects. A laboratory study using molecular docking (computer modeling) suggested an added effect with the diabetes drug acarbose on an enzyme that digests carbohydrates.
None of the sources this page has read in full reports on use during pregnancy or breastfeeding.

Safety sources: Source [1]Source [2]Source [3]Source [4]Source [5]

What the evidence says

Each claim is rated on its own evidence. Ratings follow the scale on our methodology page.

Improves muscle strength and endurance Evidence rating: Limited
People take it hoping it will make their muscles stronger and give them more stamina.
A 2026 review found no significant gain in walking distance, at low certainty, and calls strength results exploratory; a 2024 review reports strength gains but no effect on physical function.
Two reviews reach different conclusions. A 2026 systematic review and meta-analysis found five small randomized trials in 236 people, lasting 4 weeks to 4 months. They were in older adults, middle-aged adults and trained athletes, one group of them teenage footballers. Only one outcome could be pooled: the distance people walked in six minutes, from two trials. The difference from placebo was not statistically significant, and the reviewers rated its certainty low.

Strength and endurance were measured too differently to pool. Individual trials reported some improvements, such as hand and leg muscle endurance in older adults and hamstring strength in middle-aged adults. The 2026 reviewers call these "exploratory and hypothesis-generating, not reproducible evidence of efficacy".

A 2024 systematic review of five studies in 250 healthy people concluded that urolithin A increased muscle strength and endurance. It reports hamstring strength gains in the middle-aged trial, with no effect on thigh (quadriceps) or grip strength. It reports better hand and leg muscle endurance after 2 months in the older-adult trial, an effect that was not significant at 4 months. It also concludes that current evidence "does not support the beneficial effects of UA on physical function", such as walking speed and the six-minute walk. It did not rate certainty.

The reviews also judged one trial differently. The 2024 review rated the middle-aged trial at "some concerns" for risk of bias, with high risk in how its reported results were selected. The 2026 review judged that trial low risk. Because the reviews disagree, this page takes the lower reading.

The trials' own papers state that the two main trials, in middle-aged and older adults, were funded by Amazentis, a company that makes urolithin A. The papers also disclose that several of their authors worked for or advised it. In both, the main pre-planned result was not statistically significant: walking distance and muscle energy production in the older adults, and peak power output in the middle-aged adults.

Sources: Source [1]Source [2]Source [3]Source [4]
Improves the health of mitochondria, the energy-producing parts of cells Evidence rating: Limited
People take it hoping it will keep the energy-making parts of their cells working well as they age.
A 2024 review reports shifts in some muscle genes and markers but no change in maximum muscle energy output; a 2026 review calls blood-marker findings preliminary and did not grade them.
The human results here are blood and muscle markers, not measures of health. A 2024 systematic review of five studies in 250 healthy people reports on a 28-day trial in healthy older adults. The review reports that, in that trial, urolithin A switched on sets of mitochondrial genes in thigh muscle. Urolithin A also raised some markers of autophagy (the cell's recycling process) and of fat burning, with different markers moving at different doses.

The review reports that markers of how many mitochondria were made showed only trends. In a separate trial in older adults, the maximum energy (ATP) muscle mitochondria could produce did not change. The review says why some autophagy markers rose at the lower dose but not the higher one "remains unclear". It did not rate certainty.

A 2026 review of five trials describes lower blood levels of acylcarnitines and ceramides in individual trials. It did not pool them, and calls these findings "preliminary and hypothesis-generating rather than as direct evidence of improved mitochondrial health". It states that the evidence does not yet show that urolithin A meaningfully restores mitochondrial quality control in clinical settings.

That review rated the certainty only of its walking-distance result, as low, and did not rate these markers. The low certainty recorded for this claim is that walking-distance rating, which the site's rules require a claim citing the review to carry. The 4-month trial in adults aged 65 to 90, funded by Amazentis, reported in its own paper that maximum energy production in hand and leg muscle did not differ significantly from placebo.

Sources: Source [1]Source [2]Source [3]

Longevity and aging

What the cited sources report about lifespan, death from any cause, and markers studied in connection with aging. A change in a marker is not the same as a longer life. Each outcome is rated on its own evidence, on the same scale as the claims above.

Helps people live longer Evidence rating: Insufficient
People take it hoping it will help them live longer.
A 2024 review found no human study of lifespan and calls the evidence on human aging very limited; longer lifespans have been reported in worms and in a small study of male mice.
No study cited here measured lifespan or death from any cause in people. A 2024 systematic review found five human studies of urolithin A, lasting 28 days to 4 months, and none of them measured either. It concludes that "There is very limited evidence on the effect of UA in human aging".

The lifespan results are in animals. The 2024 review reports that urolithin A extended the lifespan of the roundworm Caenorhabditis elegans in a 2016 laboratory study.

A 2023 study fed urolithin A in alternate weeks to male mice from 3 months of age. It reported that "The median lifespan at 80th percentile mortality was extended 18.75%". Its figure legend gives the number of mice as 5, and its authors call for follow-up studies with more mice of both sexes. The 2024 review describes this result as an 18.5% lifespan extension in "middle-aged mice", although the study started feeding at 3 months of age.

Results in worms and a small group of mice do not show whether people live longer.

Sources: Source [1]Source [2]
Lowers blood markers of inflammation Evidence rating: Limited
People take it hoping it will lower inflammation in their body as they get older.
Two reviews report lower blood inflammation markers in some company-funded trials, but the results are mixed, the reviews disagree on one trial, and a 2026 review calls them preliminary.
The inflammation results in people are blood markers. A 2024 systematic review of five studies in 250 healthy people set out to assess whether urolithin A protects against aging. It concludes that urolithin A decreased inflammatory markers, but the results it reports are mixed.

The 2024 review reports that, in the 4-month middle-aged trial, the lower dose reduced interleukin-1 beta but not C-reactive protein (CRP), interferon-gamma or TNF-alpha. The higher dose reduced CRP, interferon-gamma and TNF-alpha but not interleukin-1 beta. Neither changed interleukin-6 or interleukin-13. The review calls the effect on interleukins inconsistent.

The sources disagree about the 4-month trial in adults aged 65 to 90. The 2024 review reports that CRP did not change compared with placebo. That trial's own report describes a significant fall in CRP from baseline in the urolithin A group but not the placebo group. A 2026 review lists lower CRP in both trials, did not pool these results, and calls its marker findings preliminary. Both trials' papers state that they were funded by Amazentis. Because the sources disagree about the older-adult trial, this page takes the lower reading.

The 2026 review rated the certainty only of its walking-distance result, as low, and did not rate CRP. The low certainty recorded for this claim is that walking-distance rating, which the site's rules require a claim citing the review to carry. A lower inflammation marker is not the same as slower aging or a longer life, and none of these sources reports lifespan or death from any cause in people.

Sources: Source [1]Source [2]Source [3]Source [4]

Sources

Effects of Urolithin A supplementation on muscle health outcomes in humans from randomized controlled trials
Frontiers in Nutrition, 2026 · Meta-analysis · Primary source · Certainty: low
Targeting aging with urolithin A in humans: A systematic review
Ageing Research Reviews, 2024 · Systematic review · Primary source
Effect of Urolithin A Supplementation on Muscle Endurance and Mitochondrial Health in Older Adults: A Randomized Clinical Trial
JAMA Network Open, 2022 · Randomized controlled trial · Supporting source
This source discloses industry funding.
Some of its authors disclose ties to industry.
Urolithin A improves muscle strength, exercise performance, and biomarkers of mitochondrial health in a randomized trial in middle-aged adults
Cell Reports Medicine, 2022 · Randomized controlled trial · Supporting source
This source discloses industry funding.
Some of its authors disclose ties to industry.
Urolithin A reduces amyloid-beta load and improves cognitive deficits uncorrelated with plaque burden in a mouse model of Alzheimer's disease
GeroScience, 2023 · Animal or laboratory study · Supporting source
GRAS (GRN) Notice 791 Agency Response Letter
U.S. Food and Drug Administration, 2018 · Health authority summary · Primary source

Page history

Show all 5 changes to this page

2026-09-28 — Rewritten to the content style guideline; ratings and sources unchanged.
2026-09-26 — Source audit. Removed two studies that could not be read in full: a 2019 trial in older adults and the 2016 laboratory study in worms and rodents. The worm lifespan result and the muscle mitochondrial gene findings are now reported as the 2024 systematic review describes them. Details found only in the two removed studies were cut, including blood acylcarnitine results from the 2019 trial, the rodent exercise results and the 2016 study's authors' company ties. The list of foods now follows the 2024 review. No rating or certainty changed.
2026-09-25 — Published. The rated claims, the longevity outcomes, the safety section and every source went through the site's source and wording reviews, and the owner approved the final pregnancy and breastfeeding wording. Its funding judgments are recorded in docs/08-open-decisions.md.
2026-09-25 — Updated from the full text of the 2024 systematic review, which had been read only as an abstract. The summaries now report its detailed findings, including mixed inflammation results and a risk-of-bias judgment that differs from the 2026 review. The lifespan summary now includes a 2023 study reporting longer median lifespan in a small group of male mice. The safety section adds the review's note on possible drug interactions from laboratory studies. No rating or certainty changed.
2026-09-25 — Drafted. Muscle strength and endurance, mitochondrial health, and lowering blood markers of inflammation rated limited; living longer rated insufficient.