Urolithin A: 5 Breakthrough Discoveries About the Molecule That Renews Your Cells by Jayney Goddard MSc, PG Dip Ed, FCMA, FRSM, Founder and President, The Complementary Medical Association
Urolithin A is a compound your gut bacteria can make from pomegranates, walnuts and berries, and it switches on mitophagy – the housekeeping process that clears out worn-out mitochondria so your cells can build fresh ones. Because failing mitochondria sit at the heart of how we age, urolithin A has become one of the most carefully studied molecules in longevity science, with a growing run of human trials behind it. Here is what the evidence actually shows, and where I think a little healthy scepticism is still wise.
I have watched a great many “miracle molecules” arrive with fanfare and leave without a trace. Urolithin A is more interesting than most, partly because the science is unusually well-organised, and partly because there is a genuine surprise tucked inside it: most of us cannot make worthwhile amounts of it at all. Let me walk you through it.
What is urolithin A, and why does it matter?
Urolithin A is what scientists call a postbiotic – a beneficial compound produced when friendly gut bacteria ferment something in your food. In this case the raw material is a family of plant polyphenols called ellagitannins, which are abundant in pomegranates, walnuts, pecans, raspberries and strawberries. You eat the pomegranate; your microbiome does the clever chemistry; urolithin A is the result.
What makes it worth your attention is the job it does once it reaches your cells. Urolithin A is one of the most reliable natural triggers of mitophagy, and mitophagy may be one of the unsung heroes of healthy ageing. Forgive me – that word is on my banned list, so let me say it plainly instead: mitophagy is one of the most underrated processes in the whole of cellular biology.
Mitophagy: your cells’ recycling crew
Every cell you own is powered by mitochondria, the tiny structures that turn food and oxygen into usable energy. Your muscles are crammed with them; so are your brain, heart and immune cells. The trouble is that mitochondria wear out, and a damaged mitochondrion is worse than useless – it leaks, it generates harmful free radicals, and it stokes the low-grade inflammation that researchers now call “inflammaging”.
Mitophagy is the disposal system that identifies these clapped-out power stations, dismantles them and recycles the parts, making room for healthy replacements. In youth it runs briskly. With age it slows, damaged mitochondria pile up, and cellular energy falls. This is why so much of the longevity field has converged on a single question: can we coax mitophagy back into action? Urolithin A is one of the few natural compounds that appears to do exactly that.
Discovery 1: It extended lifespan in worms and rebuilt muscle in animals
The modern story begins in 2016, when researchers at the École Polytechnique Fédérale de Lausanne identified urolithin A as a “first-in-class” natural inducer of mitophagy.1 In the nematode worm C. elegans – a workhorse of ageing research – urolithin A extended lifespan by roughly 45 per cent and kept the animals mobile and active for longer.1 In ageing mice and rats it improved running endurance and muscle function.1
Now, I am always wary of worm-and-mouse headlines, because the graveyard of nutrition science is full of compounds that dazzled in a Petri dish and disappointed in people. So the animal data, on its own, would not have persuaded me. What changed my mind was what came next.
Discovery 2: The first human trial confirmed it was safe and biologically active
In 2019, the first-in-human study was published in Nature Metabolism.2 Healthy older adults took urolithin A, and the researchers found it was well tolerated, absorbed properly into the bloodstream, and – crucially – that it shifted gene activity in skeletal muscle in a direction associated with improved mitochondrial health.2 In other words, the molecule was not merely safe; it was doing something measurable inside human cells. That is a meaningful step up from a worm study, and it is where urolithin A earned a place on my “worth watching” list.
Discovery 3: It improved muscle strength in middle age
The trial that turned heads landed in Cell Reports Medicine in 2022.3 Middle-aged adults took urolithin A for four months, and those on the active compound gained around 12 per cent in muscle strength compared with the start of the study, alongside improvements in aerobic endurance and walking performance.3 Their blood showed lower levels of acylcarnitines and C-reactive protein, markers that point to more efficient mitochondria and less inflammation.3
Here is the honest footnote that the breathless wellness accounts tend to omit: the study did not hit its pre-specified primary endpoint, which was peak power output.3 The strength and endurance gains were genuine and statistically robust, but in research terms, missing your primary target matters. I mention this not to dampen your enthusiasm but to model the habit of reading the small print – something I wish more of the longevity world would do.
Discovery 4: It boosted muscle endurance in older adults
A separate randomised trial, published in JAMA Network Open, tested urolithin A in adults aged 65 to 90.4 After four months, the supplemented group showed improved muscle endurance – measurably more contractions before fatigue – together with favourable changes in mitophagy-related biomarkers in the blood and muscle.4 For a population in whom muscle loss is one of the strongest predictors of frailty, falls and lost independence, that is a result worth taking seriously.
Discovery 5: The newest frontier is your ageing immune system
The most recent and, to my mind, most exciting development arrived in late 2025 in Nature Aging.5 In a placebo-controlled trial, 50 healthy middle-aged adults took 1,000 mg of urolithin A daily for four weeks.5 The supplemented group developed more “naive-like”, less exhausted immune cells – the kind of versatile T cells that decline as we age – and these cells showed greater capacity to burn fat for fuel, a sign of metabolic youthfulness.5 The researchers framed it as evidence that urolithin A may help counter immune ageing and inflammaging.5
This is early work and the trial was short, but it widens the story considerably. If mitophagy can be nudged in our immune cells as well as our muscles, we are talking about a mechanism that touches several of the core hallmarks of ageing at once.
The plot twist: most of us cannot make enough of it
Here is the detail that I find genuinely fascinating, and that reshapes the whole “just eat more pomegranates” advice. Whether your body produces urolithin A from food depends entirely on which bacteria live in your gut, and people fall into three “metabotypes”: some convert ellagitannins efficiently, some produce related compounds, and a sizeable group produce essentially none.
In one detailed study, only 12 per cent of participants had detectable urolithin A in their blood at the outset, and even after drinking pomegranate juice, only around 40 per cent converted the precursors into meaningful amounts.6 That implies the majority of us – perhaps 60 per cent in some Western populations – are poor producers, regardless of how virtuously we eat.6 It is a humbling reminder that the “diet–microbiome–health” axis is deeply personal, and that two people eating the identical pomegranate may extract entirely different benefits from it.
So how do you actually get urolithin A?
There are two routes, and they are not equal.
Through food. Eating ellagitannin-rich plants – pomegranate, walnuts, pecans, raspberries, strawberries, cloudberries – gives your microbiome the raw material. This is the approach I favour as a foundation, because these foods bring fibre, polyphenols and a host of other benefits whether or not you are a urolithin A producer. For a plant-based eater, it slots in beautifully. The honest caveat is that the amounts of urolithin A generated from food are far below the doses used in the trials, and only if you are a producer in the first place.
Through a supplement. The clinical studies used purified urolithin A (sold by a variety of supplement producers globally) at 500 to 1,000 mg per day, which sidesteps the microbiome lottery entirely and delivers a consistent dose to producers and non-producers alike.6 If you are drawn to the supplement route, that is a reasonable conversation to have with a knowledgeable practitioner, with two things kept firmly in view.
My honest take – with the confidence levels flagged
I want to be straight with you, because that is the whole point of this blog.
What I hold with reasonable confidence: urolithin A is a real biological actor, it switches on mitophagy in humans, and it has a clean safety record across several trials. That is a stronger evidence base than most “longevity” compounds can claim.
What I hold more loosely: the human benefits demonstrated so far are encouraging rather than dramatic – modest gains in strength, endurance and immune markers over a few months. We do not yet have long-term data showing it extends human healthspan, and a good deal of the research has been funded by the company that produces the supplement, which is a reason for measured rather than breathless enthusiasm.
My settled view is this: urolithin A is one of the more credible newcomers in the longevity space, and a thoroughly plant-friendly one. But it is a supporting act, not the headliner. The headliner – still, and probably always – is resistance training, which switches on mitophagy powerfully and for free. Eat your pomegranates and walnuts with pleasure. Consider a supplement thoughtfully if it suits you. And keep lifting things, because no molecule yet discovered replaces what your muscles do for your mitochondria.
Did you know… you don’t have to navigate your health journey alone?
The wellness world is full of noise, and knowing what you can genuinely trust is harder than it should be. That’s exactly where I come in. My Concierge Service offers one-to-one, personalised, evidence-based natural health guidance – tailored entirely to you, your goals and your circumstances. You receive compassionate, considered, science-informed support drawn from more than three decades in integrative medicine – so rather than second-guessing conflicting advice, you can make confident, well-founded decisions about your own healthy ageing, with someone knowledgeable alongside you.
If that’s the kind of support you’ve been looking for, I’d love to hear from you.
Frequently asked questions:
Is urolithin A safe?
Across the published human trials to date, urolithin A has been well tolerated at doses up to 1,000 mg per day, with a clean safety profile.2,3,4,5 As with any supplement, anyone who is pregnant, breastfeeding, taking medication or managing a health condition should check with a qualified practitioner first.
Can I get enough urolithin A from food alone?
Possibly, but only if your gut microbiome can convert it – and most people convert it poorly.6 Eating pomegranate, walnuts, pecans and berries is worthwhile regardless, but the amounts produced are far lower than the doses used in clinical trials.
Does urolithin A actually slow ageing?
It targets a core mechanism of ageing – mitochondrial decline – and improves several relevant markers in humans.3,4,5 However, there is no evidence yet that it extends human lifespan or healthspan, so it is best viewed as a promising tool rather than a proven anti-ageing treatment.
How is urolithin A different from a probiotic?
A probiotic is a live beneficial bacterium. Urolithin A is a postbiotic – the finished compound that certain bacteria produce from plant polyphenols. Supplementing with urolithin A delivers the end product directly, bypassing the need for the right gut bacteria.
Should I take it instead of exercising?
No. Resistance and aerobic exercise are the most powerful, best-proven activators of mitophagy, and they remain the foundation of healthy ageing. Urolithin A is at most a complement to an active life, never a substitute.
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. DOI: 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;1:595–603. DOI: 10.1038/s42255-019-0073-4
- 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. DOI: 10.1016/j.xcrm.2022.100633
- 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. DOI: 10.1001/jamanetworkopen.2021.44279
- Denk D, 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. DOI: 10.1038/s43587-025-00996-x
- Singh A, D’Amico D, Andreux PA, et al. Direct supplementation with urolithin A overcomes limitations of dietary exposure and gut microbiome variability in healthy adults to achieve consistent levels across the population. Eur J Clin Nutr. 2022;76(2):297–308. DOI: 10.1038/s41430-021-00950-1
Further reading:
The 7 Lifestyle Adjustments to Slow Your Biological Age
Sedentary Lifestyles and Ageing
About the author
Jayney Goddard MSc, PG Dip Ed, FCMA, FRSM is a leading authority on integrative medicine, healthy ageing and longevity science. President of The Complementary Medical Association, she has spent more than three decades translating cutting-edge research into practical, evidence-informed guidance. Her work bridges rigorous science and genuine warmth, with a particular focus on plant-based living, mitochondrial health and helping people thrive across a long, vital lifespan.
