What is it?

Urolithin A is a postbiotic, a compound your gut bacteria produce when they break down certain foods. You've probably heard of probiotics, the live bacteria in yogurt and supplements that support gut health, and prebiotics, the compounds (often fibers) that feed those bacteria. A postbiotic is the next step: the byproduct your gut bacteria create after doing their job.

Urolithin A is produced when gut bacteria metabolize ellagitannins, plant compounds found most abundantly in pomegranates and in some berries like raspberries and strawberries. It is not found in food itself. Your body has to make it.

Does it occur naturally in the body?

Yes, but only if your gut microbiome has the right bacteria to produce it, and a significant portion of people don't. Studies suggest that even after consuming pomegranate juice, roughly 60 percent of people produce little or no urolithin A. There is currently no standard clinical test to determine which group you fall into.

What are the claims?

Urolithin A is marketed primarily as a mitochondrial health supplement. Mitochondria are the tiny energy-producing structures inside every cell. As we age, damaged mitochondria accumulate and the body becomes less efficient at clearing them out. This buildup is associated with age-related muscle loss, fatigue, and metabolic decline.

Urolithin A is claimed to activate the cellular process that identifies and removes damaged mitochondria, essentially helping the body clean house at the cellular level. Proponents also claim benefits for muscle strength, endurance, recovery, and immune resilience.

Does it work?

There are legitimate randomized, placebo-controlled human trials on urolithin A, which puts it ahead of most supplements. But the results are more complicated than the marketing suggests.

One of the larger muscle trials enrolled 66 adults between ages 65 and 90 taking 1,000 mg daily for four months. It improved some secondary measures, including local muscle endurance and blood markers related to inflammation such as C-reactive protein. But the outcomes the researchers set out to measure before the study began told a different story. Walking distance and the muscles' ability to produce energy did not improve significantly over placebo.

A second randomized trial in sedentary, overweight middle-aged adults found that 1,000 mg daily increased leg muscle strength and improved aerobic capacity and walking distance compared with where participants started, with modest advantages over placebo. But the main outcome the researchers had targeted before the trial began, peak power output, was not significantly better than placebo.

A 2025 systematic review examining muscle outcomes found only three eligible randomized controlled trials with 174 total participants. Of 12 measured outcomes, only four reached statistical significance.

That pattern is worth sitting with. The secondary signals are real. But the outcomes researchers set out to prove in advance often don't separate clearly from placebo. That distinction matters more than any individual result.

One additional note: many of the published human trials have been funded or supported by Amazentis, the company that makes Mitopure, the leading urolithin A supplement. That doesn't mean the results are wrong, but when the same company funds most of the research on its own product, independent studies from outside researchers become important. We don't have many of those yet.

What are the dangers?

Short-term safety over several months appears good. The FDA recognized urolithin A as generally safe for use in foods in 2018. Across the clinical trials conducted so far, adverse events were minimal and comparable to placebo. No serious product-related side effects have been reported. Long-term safety data in humans does not yet exist.

The Bottom Line

Urolithin A has a real and growing human evidence base, and the science behind its mechanism is compelling. But the clinical results are mixed. Secondary measures often improve while primary endpoints fall short of statistical significance, the trial base is still small, and most of the research has been funded by the company selling the product.

Here's the practical wrinkle: urolithin A doesn't exist in food. Your gut bacteria have to make it, and if yours can't, no amount of pomegranates will help. For a significant portion of people, the supplement may be the only way to get meaningful amounts at all. The dosing used in trials runs 500 to 1,000 mg daily, and the supplement costs $75 to $100 per month.

For older adults noticing declines in endurance or recovery who already have the basics covered (training, protein, sleep, and diet quality), urolithin A is worth a conversation with your doctor or nutritionist.

Larger independent trials are underway. If those results hold up, this recommendation may look different in a few years. For now, we consider urolithin A a watch list supplement rather than a must-have.

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Reference Links:

Targeting aging with urolithin A in humans: A systematic review

Ajla Hodzic Kuerec, Xuan K. Lim, Anderson LY. Khoo, Elena Sandalova, Lihuan Guan, Lei Feng, Andrea B. Maier
Ageing Research Reviews, Published online 11 July 2024, Version of Record 16 July 2024

Click Here for the Study: https://doi.org/10.1016/j.arr.2024.102406

 

Direct supplementation with Urolithin A overcomes limitations of dietary exposure and gut microbiome variability in healthy adults to achieve consistent levels across the population

Anurag Singh, Davide D’Amico, Pénélope A. Andreux, Gillian Dunngalvin, Timo Kern, William Blanco-Bose, Johan Auwerx, Patrick Aebischer & Chris Rinsch
European Journal of Clinical Nutrition volume, Published 11 June 2021

Click Here for the Study: https://doi.org/10.1038/s41430-021-00950-1

 

Effect of the mitophagy inducer urolithin A on age-related immune decline: a randomized, placebo-controlled trial

Dominic Denk, Anurag Singh, Herbert G. Kasler, Davide D’Amico, Julia Rey, Lucía Alcober-Boquet, Johanna M. Gorol, Christoph Steup, Ritesh Tiwari, Ryan Kwok, Rafael J. Argüello, Julie Faitg, Kathrin Sprinzl, Stefan Zeuzem, Valentina Nekljudova, Sibylle Loibl, Eric Verdin, Chris Rinsch & Florian R. Greten
Nature Aging, Published 31 October 2025

Click Here for the Study: https://doi.org/10.1038/s43587-025-00996-x

 

Urolithin A improves muscle strength, exercise performance, and biomarkers of mitochondrial health in a randomized trial in middle-aged adults

Anurag Singh, Davide D’Amico, Pénélope A. Andreux, Andréane M. Fouassier, William Blanco-Bose, Mal Evans, Patrick Aebischer, Johan Auwerx, Chris Rinsch
Cell Reports Medicine, Published May 17, 2022

Click Here for the Study: https://doi.org/10.1016/j.xcrm.2022.100633

 

Effect of Urolithin A Supplementation on Muscle Endurance and Mitochondrial Health in Older Adults

Sophia Liu, Davide D’Amico, Eric Shankland, Saakshi Bhayana, Jose M. Garcia, Patrick Aebischer, Chris Rinsch, Anurag Singh, David J. Marcinek
JAMA Network Open, Published Online: January 20, 2022

Click Here for the Study: https://jamanetwork.com/journals/jamanetworkopen/fullarticle/2788244#248183557

 

Links for More Info

We at WeBeFit DO NOT recommend ANY supplements to ANY of our clients. ONLY a licensed Nutritionist or Medical Doctor can make those recommendations based on your individual needs.

This is being provided for INFORMATIONAL and EDUCATIONAL purposes only.

CAUTION: These supplements have not been evaluated by the Food and Drug Administration (FDA) for safety, effectiveness or purity. There may be unknown risks associated with taking any supplements. There are no regulated manufacturing standards for companies that make supplements. There have been instances where herbal or health supplements have been sold that were contaminated with toxic substances. If you should choose to purchase herbal or health supplements, please only purchase them from a reliable source to minimize the risk of contamination.

If you should decide to use ANY supplement, ALWAYS consult your doctor or Nutritionist first.

9/28/2008