Urolithin A: Can Better Mitochondrial Cleanup Help You Stay Stronger as You Age?
The evidence is more substantial than it is for most longevity supplements—but the details matter.
By the Bio Precision Aging Editorial Team
You can eat well, train consistently and still notice that recovery takes longer, endurance comes less easily and the energy you once took for granted is no longer automatic.
That does not always mean you need more motivation. It may mean the machinery inside your cells is becoming less efficient. Most of the cells in your body contain mitochondria—microscopic structures that convert nutrients into the usable energy required for movement, recovery, cognition, immune function and nearly every other biological process. Your muscles contain particularly large numbers of them because contracting muscle requires an enormous amount of energy.
But mitochondria do not last forever.
Like engines accumulating mileage, they become damaged over time. The body is supposed to identify the poorly functioning ones, dismantle them and recycle their usable parts. That cellular cleanup process is called mitophagy. With age, mitophagy becomes less efficient. Older, damaged mitochondria begin to accumulate, energy production becomes less reliable and inflammatory signals can increase. The result may be experienced as reduced endurance, declining muscle function, slower recovery and less resilience.
This is where Urolithin A becomes interesting. At Bio Precision Aging, we do not become enthusiastic about a supplement simply because its biological mechanism sounds impressive. The science must move through three gates:
Does the mechanism make sense?
Can researchers show that it changes human biology?
Do those biological changes translate into something people can actually feel or measure?
Urolithin A has moved further through those gates than most compounds marketed for longevity. It has been studied in animals, older adults, middle-aged adults and, more recently, human immune cells. The results are promising. They are also more nuanced than many supplement advertisements suggest.
What Is Urolithin A?
Urolithin A is not a vitamin, hormone or pharmaceutical drug. It is a postbiotic—a beneficial compound produced when certain intestinal bacteria metabolize polyphenols called ellagitannins.
Ellagitannins are found in foods including:
Pomegranates
Walnuts
Raspberries
Strawberries
Blackberries
However, eating these foods does not mean that your body will reliably produce meaningful amounts of urolithin A. Ellagitannins must first be broken down into ellagic acid. Specific gut bacteria must then complete a series of additional chemical steps that ultimately produce urolithin A [1].
The difficulty is that our microbiomes are not identical. Some people produce urolithin A efficiently, some produce very little and others appear to produce almost none. In one frequently cited human investigation, only about 40% of participants produced meaningful amounts after consuming the dietary precursors [2]. That leads to an important distinction:
Pomegranates are nutritious, but eating more pomegranate is not the same as taking a measured dose of urolithin A.
A purified supplement bypasses this microbiome lottery. In the first human clinical study, supplemental urolithin A was absorbed across the study population, with blood concentrations increasing in relation to the dose [2].
Mitophagy Without the Scientific Jargon
Think of your mitochondria as a network of power stations supplying energy to a city. Over time, some stations become outdated. They burn fuel inefficiently, produce more waste and deliver less dependable power. A well-run city removes the failing equipment and replaces it before the entire grid becomes unreliable. Mitophagy is the cellular version of that maintenance program.
When a mitochondrion loses its ability to function properly, proteins including PINK1 and Parkin help identify and tag it for disposal. The damaged mitochondrion is then broken down and recycled. Urolithin A appears to stimulate this cleanup pathway [1,3].
That is different from simply taking an antioxidant. An antioxidant may help neutralize some of the reactive molecules produced by a damaged mitochondrion. Mitophagy addresses the damaged mitochondrion itself. Urolithin A also influences pathways involved in energy regulation, fatty-acid metabolism and mitochondrial renewal. Researchers have observed changes in AMPK signaling, mitochondrial gene expression and proteins connected with the PINK1/Parkin system [2,4].
The proposed benefit is therefore not that urolithin A gives you energy like caffeine. It may help your cells maintain a healthier and more efficient population of mitochondria.
That is an important difference.
What the Research Actually Found
1. The Study That Established the Mechanism
The urolithin A story gained serious attention in 2016 when researchers published a landmark study in Nature Medicine [1]. The investigators first studied C. elegans, a microscopic worm frequently used in aging research. Urolithin A stimulated mitophagy, reduced the accumulation of dysfunctional mitochondria and helped the animals maintain movement as they aged. The worms also experienced an increase in median lifespan.
When researchers disabled key parts of the PINK1/Parkin mitophagy pathway, those benefits largely disappeared. That helped demonstrate that the results were tied to mitochondrial cleanup rather than a nonspecific antioxidant effect. The researchers then moved into mammals. Urolithin A improved exercise capacity in rodent models of age-related muscle decline and in young rats.
What this study tells us
It established a credible biological mechanism and showed that the mechanism could influence physical function across different animal models.
What it does not tell us
Worms and rodents are not humans. The study created a compelling reason to conduct human trials, but it did not prove that urolithin A would extend human lifespan or prevent age-related disease.
2. The First Human Trial: Could People Absorb It Safely?
In 2019, researchers published the first human clinical trial of urolithin A in Nature Metabolism[2]. Healthy, sedentary older adults received varying doses as either a single administration or daily supplementation for four weeks. The principal objective was safety—not whether people became stronger or lived longer.
Urolithin A was absorbed at the doses tested and did not produce a significant safety signal. After four weeks, participants receiving 500 or 1,000 mg per day showed changes in plasma acylcarnitines and skeletal-muscle gene expression. Acylcarnitines can accumulate when mitochondria are not efficiently processing fatty acids. Reductions in certain acylcarnitines were therefore interpreted as a sign of improved mitochondrial metabolism.
Muscle samples also showed changes in genes involved in mitochondrial function, fatty-acid oxidation and cellular cleanup.
What this study tells us
Supplemental urolithin A can reach the bloodstream regardless of whether someone’s gut naturally produces it. It also appears capable of changing measurable aspects of mitochondrial biology in humans.
What it does not tell us
The trial was short and was not designed to demonstrate improvements in strength, endurance, daily energy or long-term health. It showed that the biological switch could be moved. It did not yet show what moving that switch would mean in everyday life.
3. Older Adults: Better Muscle Endurance, but Not Every Outcome Improved
A 2022 randomized, double-blind, placebo-controlled trial published in JAMA Network Openenrolled 66 adults between 65 and 90 years old [3]. Participants received either 1,000 mg of urolithin A per day or a placebo for four months. Researchers measured several outcomes, including:
Six-minute walking distance
Muscle endurance in the hand and lower leg
The muscle’s maximum capacity to produce ATP
Blood markers associated with mitochondrial metabolism and inflammation
After two months, the urolithin A group performed significantly more repeated contractions before fatigue in both the hand and leg muscles than the placebo group. That is a meaningful finding. Muscle endurance is not simply an athletic metric. It affects your ability to climb stairs, carry groceries, work around the house and maintain physical independence.
But the study’s primary outcomes require a more careful reading. The urolithin A group improved its six-minute walking distance by approximately 61 meters. The placebo group also improved substantially—by approximately 43 meters. The difference between the two groups was not statistically significant.
The study also failed to find a significant difference in maximum ATP-production capacity. Blood testing was more encouraging. Urolithin A reduced several acylcarnitines and ceramides associated with inefficient mitochondrial metabolism. C-reactive protein, or CRP, also declined relative to placebo.
Our view
This was a positive trial, but not a clean sweep. The supplement improved specific measures of muscle endurance and several mitochondrial biomarkers. It did not significantly outperform placebo on the principal six-minute walk or ATP-production outcomes. The reasonable conclusion is not that urolithin A dramatically restores physical performance. It is that it may improve resistance to muscle fatigue while producing biological changes consistent with healthier mitochondrial metabolism.
4. Middle-Aged Adults: Encouraging Strength Results With Important Qualifications
A second 2022 randomized trial, published in Cell Reports Medicine, enrolled 88 adults between 40 and 64 years old [4].
Participants received:
500 mg of urolithin A per day
1,000 mg per day
A placebo
The intervention lasted four months. The headline finding was an approximately 10% to 12% improvement in two measurements of hamstring strength relative to placebo. Both the 500 mg and 1,000 mg groups improved. That result caught our attention because maintaining lower-body strength is one of the most consequential physical priorities in aging. Leg strength is closely connected with mobility, balance and independence.
There were also encouraging changes in aerobic performance. The 1,000 mg group improved peak oxygen consumption, cycling distance, gait speed and six-minute walking distance compared with its own baseline measurements. However, several of those outcomes were trends rather than statistically significant differences between urolithin A and placebo. The trial’s primary endpoint—peak cycling power—did not improve significantly compared with placebo.
The supplement also did not increase lean body mass as measured by DEXA. In other words, the strength changes were not the result of participants adding a measurable amount of muscle. Muscle biopsies provided some of the study’s most interesting evidence. Researchers found changes in proteins involved in mitochondrial metabolism and the PINK1/Parkin mitophagy pathway. CRP and other inflammatory signals also declined in portions of the supplemented groups.
Our view
This trial strengthened the case for a real physiological effect, particularly in hamstring strength.
It did not show that urolithin A builds muscle, replaces training or consistently improves every measure of aerobic performance. The practical interpretation is that urolithin A may help existing muscle function more effectively. It should not be confused with a muscle-building supplement or an alternative to progressive resistance training.
5. The Immune-Aging Study: Fascinating, but Still Early
In 2025, researchers published a randomized, double-blind trial in Nature Aging involving 50 healthy middle-aged adults [5]. Participants received either 1,000 mg of urolithin A per day or placebo for four weeks. The researchers were not testing strength or walking ability. They wanted to know whether improving mitochondrial quality could influence the aging immune system.
One of the most consistent features of immune aging is the gradual loss of naïve T cells. These are immune cells that have not yet encountered their target. You can think of them as fresh recruits capable of responding to new threats. After four weeks, the urolithin A group showed a modest but statistically significant increase in naïve-like CD8-positive T cells. Those cells also became better at using fatty acids for energy and showed evidence of greater mitochondrial biogenesis. Researchers observed additional changes in natural killer cells, nonclassical monocytes and several measures of immune-cell function.
Why this matters
Immune cells have enormous energy requirements. When their mitochondria become less effective, the immune system may become less adaptable and more prone to chronic inflammatory signaling. The study suggests that improving mitochondrial maintenance can shift certain immune cells toward a metabolically healthier, less exhausted state.
What remains unknown
The study lasted four weeks and included only 50 participants.
It did not demonstrate:
Fewer infections
Better vaccine responses
Reduced cancer risk
Faster recovery from illness
Longer life
Those are the outcomes that would establish clinical importance. For now, this is a compelling proof-of-concept study showing that urolithin A can alter human immune-cell biology. Calling it “immune-system rejuvenation” may make a good headline. Calling it a promising early signal is more scientifically accurate.
6. What About Brain Health?
The brain consumes a disproportionate amount of the body’s energy, making healthy mitochondria particularly important to neurons.
Mitochondrial dysfunction and impaired mitophagy have been observed in Alzheimer’s disease and other neurodegenerative conditions. Damaged mitochondria may increase oxidative stress, inflammation and neuronal vulnerability while interacting with amyloid and tau pathology [6].
Urolithin A has produced encouraging effects in laboratory and animal models, but that is not evidence that it prevents or treats Alzheimer’s disease in people. The registered CLARITY study is evaluating a nutritional product containing Mitopure urolithin A in approximately 650 adults. Participants are being studied for changes in self-reported cognitive function and related health outcomes over eight weeks [7].
As of this writing, the trial is active but no results have been published.
This distinction is essential:
There is a credible reason to study urolithin A for brain health. There is not yet credible human evidence that it improves cognition or prevents dementia.
The Evidence in One Sentence
Urolithin A consistently changes markers of mitochondrial biology and has produced encouraging improvements in selected measures of muscle endurance and strength—but it has not yet demonstrated that it slows aging, prevents disease or reliably improves whole-body performance. That may sound cautious. It should. Caution does not weaken good science. It separates a promising intervention from a marketing story.
Who Might Reasonably Consider Urolithin A?
The current evidence is most relevant to adults in midlife and beyond who are focused on maintaining:
Muscle strength
Resistance to fatigue
Exercise capacity
Mitochondrial health
Physical resilience with age
It may be particularly interesting for someone who notices declining endurance or recovery despite having already addressed the foundations of health.
Those foundations still come first:
Progressive resistance training
Regular aerobic and higher-intensity exercise
Adequate protein and total nutrition
Consistent sleep
Healthy body composition
Appropriate management of metabolic and cardiovascular risk
No supplement can compensate for neglecting those fundamentals.
Urolithin A is best viewed as a potential addition to a well-designed health strategy—not the strategy itself. There is not currently enough human evidence to recommend it specifically for Alzheimer’s prevention, frequent infections, poor vaccine response or the treatment of an inflammatory disease.
What Doses Have Actually Been Studied?
Human trials have most frequently evaluated 500 mg and 1,000 mg per day.
500 mg per day
This dose changed mitochondrial biomarkers in the first human study and improved selected strength measurements in the middle-aged-adult trial [2,4].
1,000 mg per day
This was the dose used in:
The four-month older-adult muscle-endurance trial [3]
One arm of the middle-aged strength trial [4]
The four-week immune-aging trial [5]
It therefore has the largest body of repeated human evidence, although “most studied” does not automatically mean “necessary for everyone.”
2,000 mg per day
This amount was included in early safety testing, but it has not been established as a superior long-term dose for strength, endurance or healthy aging.
We would not extrapolate from short-term safety testing and assume that taking more produces better results.
How Long Does It Take?
The published studies provide a practical timeline:
Four weeks: Changes in mitochondrial and immune-cell biomarkers
Two months: Improvements in certain muscle-endurance tests
Four months: Strength, endurance and metabolic outcomes assessed in the major muscle trials
A reasonable evaluation period is therefore approximately eight to 16 weeks.
That does not mean everyone will feel a noticeable difference. Several study outcomes required specialized testing, and some participants may experience biological changes without a dramatic subjective increase in energy.
How Should You Measure Whether It Is Working?
Specialized acylcarnitine panels and immune-cell profiling are useful research tools, but they are not necessary for most people.
A more practical approach is to establish a baseline and repeat the same measurements after eight to 16 weeks:
Grip strength
Six-minute walking distance
Repetitions or time to fatigue during a standardized exercise
Recovery between training sessions
Consistent cycling, rowing or treadmill performance
hsCRP when already being monitored for appropriate clinical reasons
Do not change your training program halfway through the evaluation and then attribute every improvement to the supplement. Consistency matters if you want meaningful data.
DEXA can remain useful for monitoring body composition, but urolithin A did not increase lean mass in the four-month middle-aged-adult trial [4]. It should not be evaluated as though it were a muscle-building agent.
Our PURE Encapsulations Option
For readers who prefer a practitioner-quality formulation, PURE Encapsulations offers RENUAL, which combines:
Mitopure urolithin A
Trans-resveratrol
CoQ10
Two capsules provide 250 mg of urolithin A, and the manufacturer suggests taking two capsules once or twice daily. At label dosing, that provides 250 to 500 mg per day.
That is important context. RENUAL at its suggested dose does not provide the 1,000 mg used in the older-adult endurance trial or the immune-aging trial. It does, however, provide an amount within the range that produced biomarker and strength findings in other human research.
Because RENUAL contains three active ingredients, results from studies of isolated urolithin A cannot automatically be attributed to the finished combination product.
Bio Precision Aging members can purchase through PURE Patient Direct and save 20% using provider code 329237: Access PURE Patient Direct here. After creating your account with the provider code, search for RENUAL and add it to your cart.
Use the product according to its label or the guidance of your healthcare professional. Do not increase the serving simply to reproduce a research dose without discussing it with a qualified provider.
Safety and Limitations
Across the published human studies, urolithin A was generally well tolerated, with no meaningful difference in overall adverse-event rates compared with placebo [2–5].
That is reassuring, but the evidence has boundaries.
Most controlled supplementation studies lasted between four weeks and four months. We do not yet have extensive multi-year safety data.
Additional limitations include:
No comprehensive drug-interaction studies
No established safety during pregnancy or breastfeeding
No meaningful pediatric evidence
Limited evidence in people with serious chronic illness
No established therapeutic role for neurodegenerative or immune disease
Anyone taking prescription medication—particularly anticoagulants, immunomodulatory drugs, cancer therapies or medications with narrow safety margins—should discuss supplementation with a physician or pharmacist. Supplement quality also matters. The human clinical trials used the branded Mitopure form of urolithin A. Consumers should look for clearly stated doses, reputable manufacturing and credible third-party quality testing rather than assuming that every product labeled “urolithin A” is equivalent.
An Important Note About Research Independence
Several of the major human studies were sponsored by Amazentis, the company that developed Mitopure, and a number of study authors were employees, board members or scientific advisers.
That does not invalidate randomized, placebo-controlled research. The trials were peer reviewed and published in respected journals.
It does mean that independent replication would materially strengthen the evidence.
This is part of the standard we established for Bio Precision Aging: disclose the relationship, evaluate the study design and examine the actual outcomes—not simply accept or dismiss research based on who funded it.
The Bottom Line
Urolithin A is one of the more scientifically credible compounds in the longevity-supplement category. The biological case is coherent:
Mitochondrial quality declines with age.
Impaired mitophagy contributes to that decline.
Urolithin A stimulates pathways involved in mitochondrial cleanup.
Human studies show changes in mitochondrial biomarkers.
Randomized trials have found improvements in selected measures of muscle strength and endurance.
Early research suggests that the same mechanism may influence immune-cell aging.
But the evidence does not support calling urolithin A a cure for fatigue, an exercise replacement, an Alzheimer’s preventive or a proven way to slow human aging.
We believe the most accurate description is this:
Urolithin A is a promising mitochondrial-support intervention with real human clinical evidence, measurable biological activity and encouraging—though not universal—functional results.
It has earned a place in an evidence-based healthy-aging conversation.
It has not earned a halo.
That is exactly the kind of distinction Bio Precision Aging was created to make: separating genuine scientific signal from exaggeration, explaining what the research means and helping you decide how—or whether—it belongs in your own health strategy.
References
Ryu D, Mouchiroud L, Andreux PA, et al. Urolithin A induces mitophagy and prolongs lifespan in C. elegans and increases muscle function in rodents. Nat Med. 2016;22(8):879-888. PMID: 27400265.https://doi.org/10.1038/nm.4132
Andreux PA, Blanco-Bose W, Ryu D, et al. The mitophagy activator urolithin A is safe and induces a molecular signature of improved mitochondrial and cellular health in humans. Nat Metab. 2019;1(6):595-603. PMID: 32694802.https://doi.org/10.1038/s42255-019-0073-4
Liu S, D’Amico D, Shankland E, et al. Effect of urolithin A supplementation on muscle endurance and mitochondrial health in older adults: a randomized clinical trial. JAMA Netw Open.2022;5(1):e2144279. PMID: 35050355.https://doi.org/10.1001/jamanetworkopen.2021.44279
Singh A, D’Amico D, Andreux PA, et al. Urolithin A improves muscle strength, exercise performance, and biomarkers of mitochondrial health in a randomized trial in middle-aged adults. Cell Rep Med. 2022;3(5):100633. PMID: 35584623.https://doi.org/10.1016/j.xcrm.2022.100633
Denk D, Singh A, Kasler HG, et al. Effect of the mitophagy inducer urolithin A on age-related immune decline: a randomized, placebo-controlled trial. Nat Aging. 2025;5(11):2309-2322. PMID: 41174221.https://doi.org/10.1038/s43587-025-00996-x
Jayatunga DPW, Hone E, Khaira H, et al. Therapeutic potential of mitophagy-inducing microflora metabolite, urolithin A, for Alzheimer’s disease. Nutrients. 2021;13(11):3744. PMID: 34836000.https://doi.org/10.3390/nu13113744
ClinicalTrials.gov. Impact of a Novel Brain Longevity Supplement Containing the Postbiotic Urolithin A (Mitopure) on Cognitive Function and Related Health Outcomes—CLARITY. Identifier NCT07060898.https://clinicaltrials.gov/study/NCT07060898
Disclaimer: This article is intended for educational purposes for Bio Precision Aging members and does not constitute individualized medical advice. Clinical decisions should be made in consultation with a qualified healthcare provider. Dietary supplements are not intended to diagnose, treat, cure or prevent disease. Always verify supplement quality through credible manufacturing and third-party testing standards.
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