Urolithin A · evidence
Urolithin A benefits: better evidence than most, smaller effects than claimed
The urolithin A benefits seen in randomized trials came at 500 mg to 1,000 mg daily over up to 4 months (per the 2022 ENERGIZE trial): better muscle endurance and mitochondrial markers. The effect sizes deserve a close look, and the sponsor deserves naming.
What is urolithin A, and can your body make it?
Urolithin A benefits start in the gut: bacteria make the compound from food, and a company-linked review says only about 40% of people make much of it (per D'Amico et al., 2021). Nobody eats it directly. What you eat are ellagitannins, found in these foods:
- Pomegranates, the source most trials and reviews name first
- Walnuts
- Strawberries
- Raspberries
Gut bacteria turn those ellagitannins into the compound. That conversion varies widely between people depending on microbiome composition, which is the observation the entire supplement category is built on.[1] Any honest account of the compound starts here, because the case for a capsule rests on the idea that your own gut may not do the job.
A later estimate from the company's own medical lead sits far below the figure most product pages repeat. The gap between the two numbers is the point of the next section.
Where does the 40% converter figure come from?
From a review written by scientists affiliated with Amazentis, the firm that sells the ingredient, not from an independent population survey (per D'Amico et al., 2021). The line that only about 40% of people convert ellagitannins efficiently is the core sales argument: if your gut cannot make the compound, you need to buy it.
For your decision, treat the percentage as unverified. A stool test or a dietary trial of pomegranate says more about your own conversion than a figure chosen by the seller, and the company's medical lead has since quoted a far lower share.
- What this does not say
- Conversion does vary between people; the finding is about the provenance and independence of the headline figure, not a claim that everyone produces urolithin A.
Show the numbers as a table
| Measure | Value |
|---|---|
| D'Amico review, 2021 | about 40% |
| Company CMO, 2025 | 10 to 12% |
Why conversion differs from person to person
Reviews of the compound describe a chain with several weak links: gut bacteria must break down ellagitannins, the intermediate products must be absorbed, and the body then metabolizes what arrives.[3] Microbiome composition, diet and absorption all shift the result.
That is why a direct supplement bypasses the question of whether your gut is a good producer. It is also why no single converter percentage should be treated as settled.
Why does mitophagy matter for aging?
Mitophagy matters because mitochondrial dysfunction is on the field's standard list of the ways cells decline with age, and mitophagy is how cells clear damaged mitochondria before they accumulate.[2] A compound that stimulates that process is targeting a mechanism the field agrees matters, which is more than most supplements can say.
Preclinical work supports the mechanism in muscle specifically, with reviews describing effects on inflammation and muscle protection in animal models.[3]
What urolithin A benefits have human trials shown?
Early / mixed evidence Trials showed shifts in mitochondrial biomarkers and better muscle endurance, but not the primary muscle outcomes they set out to move. A randomized placebo-controlled trial in older adults reported favorable changes in mitochondrial gene expression and plasma biomarkers, without improvement in the primary muscle endpoint.[4]
A later trial, ENERGIZE, gave 66 older adults 1,000 mg a day for 4 months and missed both primary endpoints, walking distance and peak ATP production (per Liu et al., 2022).[5] The urolithin A supplement benefits it reported, better muscle endurance and lower inflammatory markers, were secondary findings.
What ENERGIZE measured, endpoint by endpoint
ENERGIZE enrolled adults aged 65 to 90 and compared the supplement against placebo on two primary and several secondary measures (per Liu et al., 2022).[5]
- 6-minute walk distance (primary): no significant improvement over placebo.
- Maximal ATP production in hand muscle (primary): no significant improvement.
- Muscle endurance (secondary): improved at 2 months.
- Plasma acylcarnitines, ceramides and C-reactive protein, or CRP (secondary): moved in a favorable direction.
The pattern matters because the product is sold on energy and mobility. Those are the outcomes the trial named in advance, and they did not move.
Show the numbers as a table
| When | Event | Detail |
|---|---|---|
| 2019 | First-in-human trial | Biomarkers moved |
| 2021 | Sponsor review | Source of 40% claim |
| 2022 | ENERGIZE trial | Primary endpoints missed |
| 2024 | Systematic review | Healthspan unproven |
A systematic review of human evidence concluded that the compound shows potential effects on inflammation and on muscle strength and endurance, while its impact on human healthspan remains unestablished.[6] That is a fair summary of urolithin A benefits: real measured effects, no outcome result.
Reading the effect sizes
Read the effect sizes rather than the headlines. Endurance gains were measured in specific muscle groups under laboratory conditions, and the widely quoted strength percentage circulating in marketing does not correspond to a general improvement in daily function.
What this means for you: the measure that improved in ENERGIZE was a laboratory endurance test, while the walking and energy outcomes the trial named in advance did not change (per Liu et al., 2022). Judge any product claim against that split.
Does urolithin A actually work?
It depends on what "work" means, because it reliably changes mitochondrial and inflammatory biomarkers in trials, and it has moved some secondary muscle measures. It has not been shown to change walking ability, disease risk or lifespan.[6]
Who paid for the urolithin A trials?
The company that developed and sells the patented ingredient paid for the major human trials. This is normal in supplement research and it is not a scandal, since somebody has to pay for trials and nobody else was going to.
It does change how much weight a positive result carries. Sponsored trials are more likely to report favorable outcomes across all of medicine, and the appropriate response is to want independent replication rather than another study from the same source. For this compound, independent replication is thin.
What has urolithin A not been shown to do?
No effect on lifespan, no effect on age-related disease incidence, and no demonstration that the biomarker shifts translate into anything a person would notice. Cancer-related claims in circulation rest on laboratory work; institutional summaries treat the compound as investigational rather than established.[7]
Skin and appearance claims have essentially no trial support. Immune aging work is preliminary and mostly circulated through social media rather than through replicated trials.
How does urolithin A compare with other longevity supplements?
It has better human evidence than most of them, which is a low bar honestly stated. Compared with NAD precursors, where a trial raised tissue levels without improving function, urolithin A at least has functional endpoints that moved. Compared with spermidine, where supplementation barely raises plasma levels, it has demonstrated bioavailability.
Compared with exercise, which improves the same endurance measures by considerably more at no cost, it is a supplement. Our review of urolithin A products covers the commercial side, and the wider evidence review ranks it against the others.
Are urolithin A benefits worth paying for?
For some people: it has the most real human data in this category, including a 4 month trial in 66 older adults, but the gain that trial measured was a laboratory endurance test, not walking or energy (per Liu et al., 2022).[5] The mechanism targets a genuine hallmark, and tolerability is good at the doses studied.
What you are actually buying
What you are buying is a modest, laboratory-measured improvement in muscle endurance and some favorable biomarkers, from a literature funded largely by one company, at a price near the top of the category. That is a reasonable trade for some people and a poor one for others; the difference is expectations, not evidence.
Our dosage page covers the numbers used in those trials.
Frequently asked questions
How long did the trials run before anything changed?
In ENERGIZE, muscle endurance had improved at 2 months of a 4 month trial (per Liu et al., 2022). No trial in middle-aged or older adults has run for a year or longer, so nobody knows whether the change holds, grows or fades with continued use.
Can a test tell me whether my own gut makes it?
A stool test or a dietary trial of pomegranate says more about your own conversion than a population percentage chosen by the seller. A single result reflects your microbiome at one point in time, and diet can change it.
Did ENERGIZE hit the outcomes it named in advance?
No. It gave 66 adults aged 65 to 90 either 1,000 mg a day or placebo for four months and missed both primary endpoints, 6-minute walk distance and maximal ATP production in hand muscle (per Liu et al., 2022). Muscle endurance, a secondary measure, improved at 2 months.
Can food deliver the same dose as a capsule?
Nobody has shown it can. Food supplies ellagitannins, not urolithin A, and how much your gut makes depends on your microbiome. Even the seller's own estimates of good converters range from about 40% (per D'Amico et al., 2021) down to 10 to 12% (company medical lead, 2025), and no trial has compared pomegranate with a capsule.
Did the first human trial improve muscle?
Not on its primary muscle endpoint. The randomized placebo-controlled trial in older adults reported favorable changes in mitochondrial gene expression and plasma biomarkers without improving the main muscle measure (per Andreux et al., 2019). It showed the compound reaches its target, not that muscle works better.
Can urolithin A cause weight gain?
No evidence suggests it does. Body composition has been measured in some trials without a consistent finding in either direction.
Is it true only 40 percent of people can make it?
That figure is widely repeated and originates in review literature written by authors affiliated with the company commercializing the compound. The underlying observation, that gut microbiome composition determines conversion from dietary precursors, is real. The precise percentage is a marketing-friendly number worth treating carefully.
What foods contain the precursors?
Pomegranates, walnuts, strawberries and raspberries contain ellagitannins, which gut bacteria convert into urolithin A. Whether your microbiome performs that conversion efficiently varies between individuals.
How much do the muscle improvements matter?
Honestly, modestly. The endurance findings are statistically real and small in absolute terms, and they were measured in specific muscle groups under laboratory conditions rather than as an improvement in daily function.
Are the trials independent?
Largely not. The major human trials were sponsored by the company that developed and sells the patented ingredient. That does not invalidate them, and it does mean independent replication carries more weight than another sponsored study would.
What is mitophagy?
The selective recycling of damaged mitochondria, a subtype of autophagy. Its decline is part of the mitochondrial dysfunction listed among the hallmarks of aging, which is why a compound that induces it attracts serious attention.
Is it safe?
Trials have reported good tolerability at 500 mg and 1,000 mg daily over months, with no serious adverse events. As with everything in this category, that covers months rather than years.
Does it help with anything other than muscle?
Inflammatory markers have improved in some trials, and there is preliminary work on immune aging. Both are biomarker findings rather than clinical outcomes, and they need independent replication before they mean much.
Is it worth the price?
It is among the more expensive supplements in the category, and it has better human trial data than most of them. Whether modest endurance gains and biomarker shifts justify the cost is a judgment the evidence cannot make for you.
References
7 sources, all link-checked; oldest check
- The mitophagy activator urolithin A is safe and induces a molecular signature of improved mitochondrial and cellular health in humans. Andreux PA et al. Nature Metabolism 2019;1:595–603.First-in-human; authors affiliated with Amazentis (Timeline); note conflict.Verified Sep 15, 2026
- Effect of urolithin A supplementation on muscle endurance and mitochondrial health in older adults: a randomized clinical trial. Liu S et al. JAMA Network Open 2022;5(1):e2144279 (ENERGIZE; cited 249).66 older adults, 1,000 mg/day for 4 months. Both primary endpoints missed: 6-minute walk distance and maximal ATP production showed no significant treatment effect. Secondary endpoints positive: muscle endurance at 2 months, plasma acylcarnitines, ceramides and C-reactive protein all improved.Publisher blocks automated checks · last tried Sep 15, 2026
- Targeting aging with urolithin A in humans: a systematic review. Kuerec AH et al. Ageing Research Reviews 2024 (cited 84).Systematic review of human trials; potential effects on inflammation, muscle strength and endurance, with impact on healthspan not established.Publisher blocks automated checks · last tried Sep 15, 2026
- Impact of the natural compound urolithin A on health, disease and aging. D'Amico D et al. Trends in Molecular Medicine 2021 (cited 475).Review by authors affiliated with the company commercializing the compound; source of the widely repeated claim that only about 40% of people convert dietary precursors efficiently.Publisher blocks automated checks · last tried Sep 15, 2026
- Pharmacological effects of urolithin A and its role in muscle health and performance. Zhao H et al. 2023 (cited 77).Review of the mechanism and muscle-performance literature.Verified Sep 15, 2026
- Definition of urolithin A supplement. NCI Drug Dictionary, National Cancer Institute.Neutral government definition: a dietary supplement that may modulate mitochondrial activity, with potential antioxidant and anti-inflammatory effects.Verified Sep 15, 2026
- Hallmarks of aging: an expanding universe. López-Otín C et al. Cell 2023;186(2):243–278.Updated framework: twelve hallmarks.Publisher blocks automated checks · last tried Sep 15, 2026
Every link above is re-requested on a schedule by an automated checker; the date shown is when it last answered. Publishers that block automated requests are marked as such rather than reported broken. Our editorial standards explain how a source gets cited here in the first place.
Filed by the Rapamycin.store evidence desk. Each source is re-checked when the page is reviewed.
Own a longevity or health brand?
Rapamycin.store publishes sponsored and guest posts on an aged, topically-relevant domain, and offers display advertising. Tell us what you want to promote and we'll send our current options.