Does everyone make Urolithin A? A deep dive into gut health and microbial metabolism

December 25, 2025 •

4 min read

In a 2021 clinical study, only 40% of healthy adults produced measurable levels of urolithin A after consuming pomegranate juice. This surprising fact reveals that the body's ability to create this beneficial metabolite is not universal and depends heavily on the unique composition of your gut microbiome.

Quick Summary

The production of urolithin A is a metabolic process performed by specific gut bacteria from dietary polyphenols. Individual microbiomes vary, meaning many people are non-producers and miss out on potential health benefits. Supplementation can bypass this microbial barrier.

Key Points

Not a Universal Process: A significant portion of the population lacks the specific gut bacteria required to produce Urolithin A from food precursors.
Microbiome Matters: Your individual gut microbiome composition, not just diet, is the determining factor in whether you can produce Urolithin A naturally.
Health Benefits: Urolithin A is a potent postbiotic linked to improved mitochondrial health, muscle strength, and reduced inflammation.
Non-Producers Exist: Studies identify different urolithin 'metabotypes,' including a significant group that produces little to no Urolithin A (Metabotype 0).
Supplementation Bypasses Barriers: For non-producers, direct supplementation is a viable way to achieve clinically relevant levels of Urolithin A and gain its benefits.
Dietary Precursors: Consuming foods like pomegranates, walnuts, and berries provides the raw material (ellagitannins) needed for production, but only if you have the right microbes.
Age is a Factor: The ability to produce Urolithin A can also decline with age, making supplementation a more reliable option for older adults.

What is Urolithin A and How Is It Produced?

Urolithin A (UA) is a potent postbiotic, a beneficial compound created by gut microbes, and not something found directly in food. It is formed in the colon through a multi-step process involving the breakdown of polyphenols called ellagitannins and ellagic acid, found in certain foods.

The journey of Urolithin A production begins when you eat foods rich in ellagitannins, such as pomegranates, walnuts, and specific berries.

Initial Breakdown: In the stomach and small intestine, digestive enzymes start to break down ellagitannins into ellagic acid.
Microbial Conversion: The ellagic acid travels to the large intestine, where it encounters the gut microbiota. Here, specific bacterial strains, including Gordonibacter and Enterocloster bolteae, convert the ellagic acid into various urolithins, with Urolithin A being the most potent.
Absorption and Metabolism: Once produced, Urolithin A is absorbed through the intestinal wall, enters the bloodstream, and is transported to different tissues. It undergoes further metabolism in the liver and circulates as conjugated derivatives before being excreted.

Why Doesn't Everyone Produce Urolithin A?

The central reason not everyone makes urolithin A is the highly individual nature of the human gut microbiome. Just as our fingerprints are unique, so is the bacterial community living within our gut, and not everyone possesses the necessary bacterial species to complete the conversion process. Studies have categorized individuals into different "metabotypes" based on their urolithin production:

Metabotype A (UA producers): These individuals produce only Urolithin A.
Metabotype B (mixed producers): These individuals produce a mix of urolithin A and other related compounds, such as isourolithin A and urolithin B.
Metabotype 0 (non-producers): These people are unable to produce any urolithins, even when consuming foods rich in ellagitannins.

A 2021 study highlighted this variation by demonstrating that out of 100 participants given pomegranate juice, only 40% produced detectable levels of Urolithin A. This means a significant majority—around 60% in that cohort—were non-producers, with their lack of production stemming from their microbial composition, not their diet. Factors like age, poor gut health, and antibiotic use can also negatively affect urolithin-producing bacteria.

Health Implications for Non-Producers

Since Urolithin A is an active metabolite with key health benefits, non-producers may miss out on its effects. The benefits of UA are primarily linked to its ability to induce mitophagy, a cellular housekeeping process that recycles and clears out damaged mitochondria—the energy powerhouses of our cells.

Mitochondrial Health: UA stimulates mitophagy, which improves mitochondrial function and is crucial for energy production. Impaired mitophagy is associated with age-related decline.
Muscle Performance: Supplementation with UA has been linked to improvements in muscle strength and endurance, especially in middle-aged and older adults.
Reduced Inflammation: UA has antioxidant and anti-inflammatory properties that help reduce systemic inflammation.
Other Potential Benefits: Research suggests potential benefits in cardiovascular health, brain function, and joint health by protecting cells from damage.

Non-producers may not receive these advantages from diet alone, underscoring why supplementation is often considered.

Can Non-Producers Boost Urolithin A Levels?

If your gut microbiome doesn't have the right bacteria, simply increasing your intake of pomegranate or berries will not trigger Urolithin A production. For non-producers, there are two primary options:

Direct Supplementation: Taking a Urolithin A supplement provides a pre-formed, bioavailable dose that bypasses the need for microbial conversion entirely. Clinical trials show that supplementation can raise UA levels significantly, regardless of an individual's microbiome.
Support Gut Health: While not a direct solution for non-producers, supporting overall gut health with prebiotic fibers can help nourish a diverse microbiome. For those with some production capacity, this might optimize their output.

Comparison: Natural Production vs. Supplementation


Feature	Natural Production (Dietary)	Supplementation (Direct UA)
Source	Gut microbiome conversion of ellagitannins from foods like pomegranates, walnuts, and berries.	Manufactured Urolithin A delivered in capsules or powder.
Consistency	Highly variable and dependent on individual microbiome composition. Many are non-producers.	Consistent, pre-measured dose. Bypasses the microbial bottleneck.
Bioavailability	Dependent on the gut's metabolic efficiency. Levels can fluctuate.	Higher bioavailability, resulting in significantly higher and more reliable plasma levels.
Cost	Cost of food sources.	Cost of supplement product.
Effectiveness	Inconsistent for a large portion of the population; benefits may be missed.	Effective for everyone, including non-producers, delivering a clinically relevant dose.

Conclusion

The question of "Does everyone make Urolithin A?" is definitively answered with a resounding no. The capacity to produce this valuable postbiotic from dietary sources is not universal and hinges on the specific bacterial makeup of an individual's gut microbiome. The resulting variation means that many people, even those with a healthy diet, may be missing out on Urolithin A's benefits for mitochondrial function, muscle health, and longevity. For those who are non-producers or have poor conversion efficiency, direct supplementation offers a reliable and effective way to achieve clinically meaningful levels and unlock these potential health advantages. The science is clear: personalized nutrition and recognizing the role of your unique microbiome are key to accessing all the health benefits that postbiotics like Urolithin A have to offer.

Optional Outbound Link: For a deeper look into the mechanism and a key clinical trial, explore the study: Urolithin A improves muscle strength, exercise performance, and biomarkers of mitochondrial health in a randomized trial in middle-aged adults.

Frequently Asked Questions

The main reason is that their gut microbiome lacks the specific strains of bacteria necessary to metabolize ellagitannins from food into Urolithin A. These strains, like Gordonibacter species, are essential for the conversion process.

Not necessarily. While pomegranate is rich in ellagitannins (the precursors), consuming more won't help if your gut microbiome is not capable of the conversion. In fact, studies show only about 40% of people produce measurable UA from pomegranate juice.

The only way to know for certain is through a specialized gut health test that analyzes the composition of your microbiome. Companies like Tiny Health offer tests to determine your urolithin-producing capacity.

If your gut doesn't produce it, your best option is direct supplementation. Urolithin A supplements deliver a consistent and bioavailable dose that bypasses the need for microbial conversion.

Urolithin A's primary benefits come from stimulating mitophagy, the process of clearing out dysfunctional mitochondria. This supports cellular health, improves muscle strength and endurance, and has anti-inflammatory effects.

Research suggests Urolithin A can support healthy aging by improving mitochondrial function and addressing age-related decline. It helps improve muscle function, endurance, and overall cellular health, particularly in middle-aged and older adults.

Clinical trials have shown Urolithin A supplementation to be safe and well-tolerated at studied dosages (e.g., 500-1000 mg/day). As with any supplement, it's wise to consult a healthcare provider, especially if you have existing health conditions.