How Urolithin A Is Made: From Pomegranate Ellagitannins to a Standardized Supplement
Key takeaways
- You cannot eat urolithin A. It is a metabolite — a by-product your gut microbiome creates from plant precursors called ellagitannins.
- The conversion runs in three steps: ellagitannins are hydrolyzed to ellagic acid, which specific gut bacteria then transform through intermediate urolithins into urolithin A.
- Whether you produce meaningful urolithin A depends on your “metabotype.” A substantial share of people make little or none, no matter how many pomegranates they eat.
- Standardized urolithin A delivers the finished molecule directly, so the result does not depend on your personal gut bacteria. Human trials confirm direct intake raises blood levels reliably.
- “Standardized” on a label means a defined, verified amount of the identified compound — the single most useful thing to look for in a quality product.
If you have read that pomegranates are a source of urolithin A, that is a useful shorthand — but it is not quite how the biology works. Pomegranates do not contain urolithin A at all. What they contain are the raw materials. Turning those raw materials into urolithin A is a job handled entirely by the trillions of bacteria living in your large intestine, and not everyone’s microbiome is up to the task. Understanding how urolithin A is actually made explains why a food-first strategy is unreliable for many people, and why standardized supplements exist in the first place.
Why can’t you just eat urolithin A?
Urolithin A belongs to a class of molecules called postbiotic metabolites. A postbiotic is a compound produced by gut bacteria as they ferment something you’ve eaten, rather than a compound present in the food itself. In this case, the food supplies ellagitannins — large polyphenols concentrated in pomegranates, walnuts, pecans, and certain berries such as raspberries and strawberries.
Ellagitannins are far too large and complex to be absorbed intact in any meaningful quantity. They pass through the stomach and small intestine largely untouched and arrive in the colon, where the real chemistry begins. This is why no amount of pomegranate juice puts urolithin A directly into your bloodstream: the fruit delivers a precursor, not the active metabolite. Reviews of ellagic acid metabolism describe this precursor-to-postbiotic journey as the defining feature of the whole urolithin family (Ellagic Acid and Gut Microbiota, 2025).
The three-step conversion, explained
From plant to postbiotic, urolithin A is built in a short but demanding sequence. Each step depends on the one before it, and the final step depends on having the right bacteria present.
| Step | What happens | Where |
|---|---|---|
| 1. Ellagitannins | Large polyphenols from food are hydrolyzed (broken apart by water and enzymes) into smaller units. | Stomach & upper gut |
| 2. Ellagic acid | The released ellagic acid is poorly absorbed on its own and travels onward to the colon. | Small intestine → colon |
| 3. Urolithins | Specific gut bacteria cleave and reduce ellagic acid through a series of intermediate urolithins (M5, M6, C, D) to reach urolithin A. | Large intestine (colon) |
That third step is the bottleneck. Laboratory work has shown that ellagic acid will sit essentially unchanged unless the right microbial species are present to run the conversion — researchers have reproduced the full ellagic-acid-to-urolithin-A pathway in vitro only when they supply gut bacteria from people who are natural producers (Applied Microbiology & Biotechnology, 2024, PRECLINICAL). Members of the Gordonibacter and Ellagibacter genera, among others, have been identified as key players in generating the different urolithin end-points (Journal of Agricultural & Food Chemistry, 2023).
Why your gut bacteria are the deciding factor
Because the last step is microbial, the amount of urolithin A you make from a given meal depends on which bacteria you happen to host. Researchers classify people into urolithin metabotypes:
| Metabotype | What it produces | Practical meaning |
|---|---|---|
| Metabotype A | Primarily urolithin A | Efficient producers of the molecule most studied for cellular benefits |
| Metabotype B | Urolithin A plus urolithin B and isourolithin A | Mixed output; variable urolithin A levels |
| Metabotype 0 | Little or no urolithin production | Eating the precursors yields essentially no urolithin A |
Studies of metabotype distribution consistently find that a large minority of adults fall outside efficient urolithin A production — and metabotype can shift with age, diet, and gut health (Urolithins in Clinical Translation, 2025). In other words, two people can eat the identical bowl of walnuts and berries and end up with very different urolithin A levels in their blood. This is the core limitation of relying on food alone, and it is the problem standardized supplements were designed to solve.
How supplement-grade urolithin A is made
Rather than hoping your microbiome performs the three-step conversion, a standardized supplement supplies the finished urolithin A molecule directly. The compound is manufactured to a defined chemical specification and verified for identity and purity, so each dose contains a known, consistent amount regardless of who is taking it. Because the molecule is delivered ready-made, it does not need the Gordonibacter-type bacteria that natural production requires — the converter-status lottery is bypassed entirely.
Does delivering it directly actually raise urolithin A in the body? Human data say yes. In a first-in-human study, direct oral urolithin A was well tolerated and reliably increased plasma urolithin A, while also shifting a molecular signature associated with mitochondrial function (Andreux et al., Nature Metabolism, 2019, HUMAN). Later randomized trials in middle-aged and older adults used the same direct-delivery approach and measured urolithin A exposure along with muscle and mitochondrial biomarkers (Singh et al., Cell Reports Medicine, 2022, HUMAN; Liu et al., JAMA Network Open, 2022, HUMAN). The broader translational literature frames this “skip the conversion” logic as the central reason direct supplementation is studied at all (Health Benefits & Mechanisms of Urolithin A, 2025).
What “standardized” actually means on a label
Standardization is a quality concept, not a marketing word. A standardized urolithin A product states a specific milligram amount of identified urolithin A and is tested to confirm the material matches that claim. That is different from a vague “pomegranate complex” or “ellagic acid blend,” which supplies precursors and leaves the hard conversion step to your gut. If your goal is urolithin A itself, the label should name urolithin A and a dose — not just its plant precursors.
SOMA Urolithin A gummies take exactly this approach: a defined 1,000 mg dose of standardized urolithin A per serving, so the amount you take doesn’t depend on your personal microbiome.
Frequently asked questions
Is urolithin A natural if it’s made in a lab?
Urolithin A is a naturally occurring human metabolite — your own gut bacteria make it. Supplement-grade material is the same identified molecule, produced to a consistent specification so the dose is reliable. The difference is consistency and verification, not the identity of the compound.
If I eat a lot of pomegranate, do I still need a supplement?
It depends entirely on your metabotype. Efficient producers (metabotype A) may generate some urolithin A from food, while metabotype 0 individuals make essentially none regardless of intake. Because you can’t easily know your status, a standardized dose removes the guesswork.
Can I change my gut bacteria to become a producer?
Metabotype can shift somewhat with diet and gut health over time, but it is not a switch you can reliably flip, and the research here is still early. For a predictable amount of urolithin A, direct supplementation is the more dependable route.
Why is dosing listed in milligrams of urolithin A?
Because urolithin A is the studied compound, reputable products specify milligrams of standardized urolithin A — not milligrams of pomegranate extract or ellagic acid, which are precursors and don’t translate one-to-one into urolithin A.
Does cooking or juicing pomegranate create urolithin A?
No. Processing can affect ellagitannin content, but the conversion to urolithin A happens only in your colon via bacteria — not in the kitchen.
Support your cellular health, every day
SOMA delivers a high-potency 1,000 mg dose of Urolithin A in one simple daily gummy — no guesswork, no converter-status lottery.
Shop SOMA Urolithin A Gummies →These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.