Urolithin A

Urolithin A is a compound your gut bacteria make when they break down substances called ellagitannins, found in foods like pomegranates, walnuts, and berries. Only some people produce meaningful amounts naturally, which is why it is now sold directly as a supplement. It has genuine, registered human clinical trials behind it, including a well-known muscle-strength study, giving it one of the stronger human evidence bases among the compounds covered on this site, though the specific doses and populations studied are narrower than marketing often suggests.

Research snapshot

Peptide category	Small-molecule gut-microbiome metabolite (not a peptide), derived from dietary ellagitannins
Primary research interest	Mitochondrial function and muscle strength support (mitophagy-related mechanism)
Highest available evidence	Tier 1/2 — registered human clinical trials exist, including a well-known muscle-strength study; one of the stronger human evidence bases among compounds on this site, though studied doses/populations are narrower than marketing suggests
Human research available	Yes, registered human clinical trials
Development status	Commercialized supplement ingredient (notably the patented Mitopure brand); not a pharmaceutical drug candidate in active development identified in this review
Regulatory status	Not an approved pharmaceutical drug. FDA responded without objection to a 2018 GRAS notification for food-ingredient use within a specified content range — a food-safety determination, not approval of a health claim. Sold as an unregulated dietary supplement in the US

Technical identity

Primary name	Urolithin A
Alternative names	Marketed under the patented brand name Mitopure (licensed by Amazentis)
Peptide sequence	Not applicable — this is a small-molecule metabolite, not a peptide
Amino-acid length	Not applicable — this is a small-molecule metabolite, not a peptide
Molecular formula	Commonly cited as C13H8O4; not independently re-verified in this pass
Molecular weight	Commonly cited around 228.2 g/mol; not independently re-verified in this pass
CAS Registry Number	Commonly cited as 1143-70-0; not independently re-verified in this pass
PubChem CID	Not independently re-verified in this pass
Peptide class	Not applicable — a gut-microbial metabolite of dietary polyphenols (ellagitannins)
Primary biological target	Proposed to promote mitophagy (clearance of damaged mitochondria), supporting mitochondrial function
Developer or originator	Naturally occurring gut-bacterial metabolite; not synthetically invented, though commercialized as Mitopure by Amazentis
Development status	Commercialized dietary supplement ingredient; GRAS food-ingredient status for a specified range as of 2018

What it is

Urolithin A is not itself present in the foods you eat. It is a metabolite, meaning it is produced when gut bacteria break down ellagitannins, a class of polyphenol compounds found in pomegranates, walnuts, raspberries, strawberries, and certain other plants. Whether a given person produces meaningful amounts of Urolithin A after eating these foods depends heavily on their individual gut microbiome composition; research has found that a substantial portion of people are “low producers” or “non-producers” of Urolithin A even when consuming ellagitannin-rich foods, which is a major part of the rationale for selling Urolithin A directly as a supplement rather than simply recommending pomegranate consumption.

Scientific interest in Urolithin A grew from research into mitophagy, the cellular process of clearing out damaged mitochondria (the cell’s energy-producing structures) so they can be replaced with healthy ones. This research area was significantly advanced by academic groups including those at EPFL (École Polytechnique Fédérale de Lausanne) in Switzerland, and commercialized by the company Amazentis, which developed a purified, patented Urolithin A ingredient sold under the brand name Mitopure and licensed to various supplement companies. A substantial share of the published human clinical trial evidence for Urolithin A specifically involves this purified Mitopure ingredient rather than Urolithin A derived generically from food.

In 2018, the U.S. FDA responded favorably to a Generally Recognized As Safe (GRAS) notification for Urolithin A at specified levels in food products, which is a food-safety determination, not an approval of any health or efficacy claim.

How does it work?

Plain-English explanation

As cells age, some of their mitochondria (the tiny structures that produce energy) become damaged and less efficient. Normally, cells have a cleanup process that identifies and removes these damaged mitochondria so new, healthy ones can take their place, but this cleanup process, called mitophagy, becomes less efficient as we get older. Urolithin A is studied because it appears to help stimulate this cleanup-and-renewal process in muscle and other tissue, which is the proposed reason it has shown effects on muscle strength and endurance in some human and animal studies.

Technical explanation

Urolithin A is proposed to induce mitophagy through mechanisms studied in preclinical models, including effects on mitochondrial membrane potential and interaction with autophagy-related signaling pathways; the precise, complete mechanistic pathway in human tissue is still being characterized in ongoing research rather than fully settled. It belongs to the urolithin class of compounds, which also includes related metabolites such as Urolithin B, and its formation from dietary ellagitannins proceeds through intermediate metabolites (including ellagic acid) via sequential gut bacterial metabolism, a process that varies substantially between individuals based on their specific gut microbial communities, commonly grouped in research into distinct “metabotype” categories reflecting different capacities to produce Urolithin A.

Potential benefits and research applications

Muscle strength and exercise performance in middle-aged and older adults

What is being investigated: whether Urolithin A supplementation improves muscle strength and physical performance measures. How the effect might occur: via enhanced mitophagy and improved mitochondrial health in muscle tissue. Evidence: a randomized, placebo-controlled human trial published in Cell Reports Medicine in 2022 studied 88 middle-aged and older adults (ages 40-64) given either 500 milligrams or 1,000 milligrams of Mitopure Urolithin A daily for four months, reporting improvements in hamstring and knee flexion muscle strength in both dose groups, along with biomarker improvements in mitochondrial health and reduced inflammation markers; the higher dose group also showed some improvements in aerobic endurance and six-minute walk test distance, though those specific measures were not reported as reaching statistical significance. Strength: has been shown in a registered, published, placebo-controlled human clinical trial, one of the stronger evidence bases among longevity compounds covered on this site. Limitation: this is one trial (plus a related earlier trial in older adults on muscle endurance) from a specific research and commercial program; broader replication across independent research groups is more limited, and effect sizes, while statistically significant for some measures, were moderate.

Muscle endurance and mitochondrial biomarkers in older adults

What is being investigated: whether Urolithin A supplementation improves muscle endurance and mitochondrial health biomarkers specifically in older adults. How the effect might occur: through the same proposed mitophagy-enhancing mechanism. Evidence: an earlier randomized clinical trial (published around 2022) in older adults reported improvements in muscle endurance measures and biomarkers associated with mitochondrial health following Urolithin A supplementation. Strength: published human randomized clinical trial evidence. Limitation: as with the strength trial, this remains a limited number of trials from a concentrated research program rather than a broad, independently replicated evidence base.

General cellular aging and mitochondrial health (“healthspan”)

What is being investigated: whether Urolithin A’s mitophagy-inducing effects translate into broader anti-aging or healthspan benefits beyond muscle-specific outcomes. How the effect might occur: by improving mitochondrial quality control across multiple tissue types, based on the compound’s core proposed mechanism. Evidence: extensive preclinical (cell and animal) research supports the mitophagy mechanism and shows benefits across various rodent models of aging and muscle function; human evidence to date is concentrated specifically in the muscle-strength and endurance trials described above rather than broader outcome measures like cognitive function, cardiovascular outcomes, or lifespan. Strength: is being investigated for broader healthspan benefits, but has been established specifically only for the muscle strength/endurance outcomes measured in the published human trials, not for broader anti-aging claims. Limitation: marketing for Urolithin A products sometimes extends the muscle-strength findings into broader “anti-aging” or “cellular health” claims that go beyond what the specific published human trials actually measured.

What dosage information circulates?

Figures in this section summarize amounts and schedules reported in published research or circulating online. Their inclusion documents what is reported and does not establish that a regimen is verified, safe, effective, or appropriate.

Amounts studied in human research

The 2022 Cell Reports Medicine randomized controlled trial in 88 middle-aged and older adults used oral doses of 500 milligrams or 1,000 milligrams per day of Mitopure (purified Urolithin A), taken daily for four months, with both doses showing improvements in muscle strength measures and the 500 milligram dose showing a numerically larger effect on hamstring strength in that particular trial (evidence category: published human clinical trial, randomized and placebo-controlled). An earlier published clinical trial in older adults, studying muscle endurance and mitochondrial biomarkers, used a broadly similar oral daily dosing approach with Urolithin A, though details of that specific protocol are reported in its own original publication. Earlier safety and tolerability studies in elderly and middle-aged human subjects, conducted prior to the efficacy trials, reported that oral Urolithin A was well tolerated across a range of tested doses.

Amounts studied in animal research

Preclinical rodent studies investigating Urolithin A’s mitophagy and muscle-function effects have used oral doses in various ranges reported across the literature, commonly on the order of tens of milligrams per kilogram of body weight per day in mouse studies, administered over periods of weeks to months depending on the specific research question; exact figures vary between individual published studies and research groups and are not standardized into one reference animal protocol (evidence category: published animal research).

Practitioner and community-reported protocols

Supplement vendors selling Urolithin A products, most of them licensing or referencing the Mitopure ingredient, commonly recommend daily doses in the range of 500 to 1,000 milligrams, which directly tracks the doses used in the published clinical trial described above rather than being an independently invented community figure. This is one of the more directly source-traceable dosage ranges among the compounds covered on this site, since the commercial dosing recommendation and the clinical trial dosing largely overlap (evidence category: vendor-reported, but directly aligned with published human clinical trial dosing rather than of unclear origin). Community longevity forums generally repeat this same 500 to 1,000 milligram daily range rather than promoting a substantially different figure.

Side effects, risks, and limitations

Published human trials, including safety studies in elderly subjects, have reported Urolithin A as generally well tolerated, with only mild side effects noted in the safety and efficacy trials reviewed for this entry. In vivo (animal) studies have not identified significant toxicity or specific adverse effects from dietary Urolithin A intake at the levels studied. That said, the total number of published human trials remains relatively small and concentrated around a specific research and commercial program (largely tied to Amazentis and the Mitopure ingredient), so broader long-term safety data across diverse populations and over multi-year use has not been established. As with other supplements, individual gut-microbiome-derived “natural” Urolithin A production varies enormously between people, and this variability itself has not been shown to create any specific safety concern, but it does mean that dietary intake alone (without direct supplementation) produces highly inconsistent Urolithin A exposure across individuals.

Regulatory and developmental status

Urolithin A is not an approved pharmaceutical drug. In 2018, the FDA responded without objection to a Generally Recognized As Safe (GRAS) notification covering Urolithin A use in food products within a specified content range (reported around 250 milligrams to 1 gram per serving in food-product contexts), which is a food-ingredient safety determination rather than an approval of any specific health claim. It is sold in the United States as an unregulated dietary supplement ingredient, most prominently under the patented Mitopure brand licensed by Amazentis to multiple supplement manufacturers, meaning individual products are not required to independently prove efficacy before sale even though some of the underlying research was conducted specifically on the Mitopure ingredient.

Frequently asked questions

What is Urolithin A?

Urolithin A is a compound produced when gut bacteria break down ellagitannins, plant compounds found in pomegranates, walnuts, and berries. Because not everyone’s gut bacteria produce meaningful amounts naturally, it is now also sold directly as a purified supplement.

How does Urolithin A work?

It is studied for its ability to promote mitophagy, the cellular process of clearing out damaged mitochondria so they can be replaced with healthier ones, particularly in muscle tissue.

What dosage has been studied in human trials?

A randomized, placebo-controlled trial in 88 middle-aged and older adults used 500 milligrams or 1,000 milligrams per day of Mitopure Urolithin A for four months and reported improvements in muscle strength at both doses.

What dosage information circulates for supplements?

Vendors selling Urolithin A supplements, primarily under the Mitopure ingredient brand, commonly recommend 500 to 1,000 milligrams per day, closely tracking the dose used in the published clinical trial.

Has Urolithin A been studied in humans?

Yes. It has one of the more substantial human clinical trial bases among longevity compounds, including a published randomized, placebo-controlled muscle-strength trial, though the number of independent trials remains relatively small overall.

Is Urolithin A FDA-approved?

It is not an approved drug. The FDA responded favorably to a GRAS (Generally Recognized As Safe) food-safety notification for Urolithin A in 2018, which addresses food safety, not efficacy for any health claim.

What foods contain Urolithin A?

No food contains Urolithin A directly. It is produced by gut bacteria after eating ellagitannin-rich foods like pomegranates, walnuts, raspberries, and strawberries, and production varies significantly between individuals based on their gut microbiome.

What remains unknown?

Whether Urolithin A produces broader anti-aging or healthspan benefits beyond the specific muscle-strength and endurance outcomes measured in published trials, and its long-term safety over years of continuous use in large, diverse populations, have not been established.

Bottom line

Urolithin A has one of the stronger human clinical trial foundations among the compounds covered on this site: a registered, published, placebo-controlled trial in middle-aged and older adults showed measurable muscle-strength benefits at doses of 500 and 1,000 milligrams per day. What the current evidence does not support is the broader “anti-aging” and general healthspan framing sometimes used in marketing, since published human trials have focused specifically on muscle strength, endurance, and mitochondrial biomarkers rather than aging or lifespan outcomes generally. It is GRAS-cleared for food use, not FDA-approved as a drug, and sold as an unregulated dietary supplement, most commonly under the patented Mitopure ingredient brand.