What Is Ellagic Acid? (And Its Link to Urolithin A)

Ellagic acid is a plant polyphenol found in pomegranates, walnuts, and berries. On its own it is interesting, but its most talked-about role is upstream: it is the raw material your gut can transform into urolithin A, the postbiotic behind much of today's mitochondrial-health research.

What ellagic acid actually is

Ellagic acid is a naturally occurring polyphenol — a class of protective compounds that plants make in large amounts. In most foods it does not travel around as free ellagic acid. Instead it is bound up in larger molecules called ellagitannins, a family of hydrolyzable tannins that are especially concentrated in pomegranate, walnuts, chestnuts, and berries such as raspberries, strawberries, and blackberries. When you eat these foods, digestive enzymes and gut conditions slowly release ellagic acid from those tannins.

Chemically, ellagic acid is a compact, four-ringed structure with several hydroxyl groups. Those groups are what give it its well-documented antioxidant behavior in the laboratory: they can neutralize reactive molecules and bind certain metals. That same tightly packed structure, however, is also why ellagic acid is famously hard for the human body to absorb on its own. It is poorly soluble, and only a small fraction of what you swallow crosses into the bloodstream intact.

How ellagic acid works in the body

There are really two stories here, and keeping them separate is the key to understanding ellagic acid honestly.

1. Direct antioxidant activity

In cell and test-tube studies, ellagic acid behaves as an antioxidant — it helps neutralize free radicals and supports the body's own defenses against oxidative stress. This is the property most often highlighted on supplement labels. It is genuine chemistry, but most of it has been demonstrated in preclinical settings (cells and animals), and because absorption of free ellagic acid is low, how much of this activity translates to a meaningful effect in people from diet alone is still being studied.

2. The gut-conversion story: from ellagic acid to urolithins

This is where ellagic acid becomes far more interesting. Once ellagitannins and ellagic acid reach the colon, resident gut bacteria can metabolize them into a family of compounds called urolithins — the most studied of which is urolithin A. In other words, ellagic acid is best understood as a precursor: the tap water that your microbiome may or may not turn into something more bioavailable and biologically active.

The catch is individuality. Only some people carry the specific gut bacteria needed to convert ellagitannins efficiently into urolithin A. Research on “urolithin metabotypes” suggests a meaningful share of adults produce little or none, even when they eat plenty of pomegranate or walnuts. That single fact explains why two people can eat the same handful of berries and end up with very different levels of the downstream postbiotic.

Ellagic acid, urolithin A, and mitophagy

The reason the ellagic-acid-to-urolithin pathway matters for healthy aging comes down to mitochondria — the tiny structures that generate most of your cells' energy. Over time, mitochondria wear out, and cells rely on a housekeeping process called mitophagy to identify and recycle the worn-out ones so fresh, efficient mitochondria can take their place. When mitophagy slows with age, damaged mitochondria accumulate.

Urolithin A — the gut-made product of ellagic acid — is the molecule shown to support mitophagy. The foundational work here is preclinical: Ryu et al. (2016, Nature Medicine) demonstrated that urolithin A induced mitophagy, extended lifespan in C. elegans, and improved muscle function in rodents. That is animal and worm data, not human proof, and it is important to label it as such. What it does establish is a plausible mechanism, and it points to why researchers moved from studying dietary ellagitannins to studying purified urolithin A directly.

What the human research on urolithin A shows

Because ellagic acid's most compelling role is as a urolithin A precursor, it is worth being precise about what has actually been tested in people — using purified urolithin A, not ellagic acid.

Proven in human trials

The first-in-human safety study, Andreux et al. (2019, Nature Metabolism), found urolithin A was safe and well tolerated up to 1,000 mg per day and produced a mitochondrial gene-expression signature in older adults. A randomized trial in older adults (Liu and D'Amico et al., 2022, JAMA Network Open) reported improvements in muscle endurance — measured as the number of muscle contractions before fatigue — over roughly four months. Singh et al. (2022, Cell Reports Medicine) studied middle-aged adults over four months with 500 mg and 1,000 mg arms and reported benefits to muscle strength and exercise performance.

Newer human research

A 2025 randomized trial in Nature Aging (roughly 28 days) reported that urolithin A supported the mitochondrial health of immune cells in midlife adults, a line of work relevant to age-related low-grade inflammation. An 8-week randomized trial in resistance-trained men (Journal of the International Society of Sports Nutrition, 2024) looked at endurance and recovery markers, and a 2025 trial explored effects in distance runners.

Honest limitations

A 2024 systematic review in Ageing Research Reviews — “Targeting aging with urolithin A in humans” — concluded that the human evidence is still emerging, with relatively short trials and modest sample sizes. The muscle findings are the most consistent; other areas remain early. For a fuller breakdown, see our clinical studies overview.

Food sources of ellagic acid

If you want to raise your dietary intake of ellagitannins and ellagic acid, the richest sources are consistent across the research: pomegranate (juice and arils), walnuts, and berries — particularly raspberries, blackberries, and strawberries. Chestnuts and some oak-aged foods contribute smaller amounts. Whole fruit and nuts also deliver fiber and other polyphenols, so they are a sensible addition to most diets regardless of the urolithin question. You can read more in our guide to foods high in urolithin A.

The honest limitation of the food-first approach is the one already noted: eating the precursor does not guarantee you make the active compound. That depends on your individual microbiome.

Safety and who should be cautious

Ellagic acid consumed as part of normal foods — berries, pomegranate, walnuts — is generally regarded as safe and has a long history of dietary intake. Concentrated supplements are a different matter: they are less standardized, and high-dose polyphenol extracts can interact with medications and vary widely in quality. This is a good moment for the important disclaimer: ellagic acid is not a treatment for any disease. If you are managing a metabolic condition, take prescription medication, are pregnant or breastfeeding, or have a chronic health issue, talk to your doctor before adding any concentrated ellagic acid or polyphenol supplement — this article is educational and not medical advice.

For those who supplement urolithin A directly, the human safety data is more defined: it has been well tolerated in trials up to 1,000 mg per day. Details on tolerability are covered in our side effects guide.

Ellagic acid vs. urolithin A: which should you focus on?

Think of it as a supply chain. Ellagic acid is upstream raw material; urolithin A is the finished, studied product. If your microbiome converts efficiently, ellagitannin-rich foods may be enough. If it does not — and many people's does not — then supplementing urolithin A directly bypasses the uncertainty entirely. That is exactly why SOMA HEALTH formulated a urolithin A product rather than an ellagic acid one. To weigh formats and doses, see our roundup of the best urolithin A gummies and our dosage guide.

*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. This guide is educational and is not a substitute for advice from a qualified healthcare provider.