Urolithin A vs NAD+ (and NR): How They Differ

Urolithin A and NAD+ precursors like nicotinamide riboside are often shelved side by side as cellular energy supplements, which makes them sound interchangeable. They are not. They work on different parts of the same system, and understanding that difference is the key to deciding whether you want one, the other, or an honest reason to consider both.

Two different jobs inside the mitochondria

Almost every cell in your body relies on mitochondria to convert food and oxygen into usable energy. Keeping that system running well involves two broadly separate challenges: having enough of the right molecular fuel and cofactors to run the chemistry, and clearing out the mitochondria that have become damaged so they do not drag down the rest. Urolithin A and NAD+ precursors each address one of these challenges, and largely not the other.

Put simply, NAD+ is about supply. Urolithin A is about renewal. That single distinction explains most of the differences that follow.

What NAD+ and NR actually do

NAD+ (nicotinamide adenine dinucleotide) is a coenzyme found in every cell. It is a workhorse of metabolism, shuttling electrons through the reactions that generate cellular energy and acting as a required cofactor for enzymes involved in DNA repair and in the activity of sirtuins, a family of proteins linked to metabolic regulation. Cellular NAD+ availability is understood to decline with age, which is the central rationale behind supplementing with NAD+ precursors.

Nicotinamide riboside (NR) and the related molecule nicotinamide mononucleotide (NMN) are precursors: the body takes them up and uses them to raise NAD+ levels through what is known as the salvage pathway. In other words, NR does not act directly; it is raw material the cell converts into more NAD+, topping up the coenzyme pool so that NAD+-dependent reactions have what they need. The theory is intuitive: if NAD+ falls with age and NAD+ drives energy metabolism, restoring it may support cellular function. Human research on NR is active but mixed. NR reliably raises blood NAD+ markers, yet its downstream effects on outcomes such as muscle mitochondrial content and physical performance have been inconsistent across trials, with some well-conducted studies finding little measurable change. NR raises the supply; whether that supply translates into the outcomes people hope for is still being worked out.

What urolithin A does differently

Urolithin A does not raise NAD+ and is not a coenzyme. It is a gut postbiotic, produced when gut bacteria metabolize the ellagitannins found in pomegranate, walnuts and certain berries, and notably only some people's microbiomes convert it well. Its defining action is to support mitophagy, the quality-control process that identifies worn-out mitochondria and recycles them so healthier ones can take their place. You can read the mechanism in plain language in our explainer on what mitophagy is.

The distinction is worth restating because it is the whole point. NR tries to give existing mitochondria more of the coenzyme they run on. Urolithin A tries to improve the quality of the mitochondrial population itself by clearing the damaged units. One is a fuel-and-cofactor strategy; the other is a maintenance-and-renewal strategy. They are not competing versions of the same idea. For a fuller picture of urolithin A on its own, see our complete urolithin A guide.

Comparing the evidence, honestly

Neither ingredient should be sold on hype, so here is where each actually stands.

Urolithin A human evidence (strongest first)

Andreux and colleagues (2019, Nature Metabolism) reported in a first-in-human study that urolithin A was safe and well tolerated up to 1,000 mg per day and produced a mitochondrial gene-expression signature. Liu, D'Amico and colleagues (2022, JAMA Network Open) found improvements in muscle endurance, measured as contractions before fatigue, in older adults over roughly four months. Singh and colleagues (2022, Cell Reports Medicine) reported benefits for muscle strength and exercise performance in middle-aged adults using 500 mg and 1,000 mg arms. A 2025 Nature Aging randomized trial found urolithin A supported immune-cell mitochondrial health in midlife adults over about 28 days. An 8-week randomized trial in resistance-trained men (Journal of the International Society of Sports Nutrition, 2024) examined endurance and recovery markers. A 2024 systematic review in Ageing Research Reviews fairly characterizes this as emerging evidence from short trials of modest size.

Urolithin A preclinical evidence (animal and cell, not human proof)

The foundational study by Ryu and colleagues (2016, Nature Medicine) showed urolithin A induced mitophagy, extended lifespan in C. elegans, and improved muscle function in rodents. These results generated the hypotheses that the human trials went on to test, but they are not themselves human proof.

NAD+ precursor evidence

NR has a solid track record for raising NAD+ blood markers in humans and a generally reassuring short-term safety profile in trials. Its effects on functional outcomes such as muscle performance and mitochondrial content have been less consistent, with several controlled studies reporting no significant change. Both ingredients, in short, are areas of active research rather than settled science, and anyone claiming otherwise is overreaching.

Do they compete, or complement?

Because they act on different steps, urolithin A and NAD+ precursors are best understood as potentially complementary rather than as substitutes. One is oriented toward the coenzyme supply that mitochondria use; the other toward recycling the mitochondria themselves. There is a coherent biological rationale for interest in both, and they are not known to work against each other. That said, complementary in theory is not the same as proven better together. There is no large human trial establishing that combining them outperforms either alone, so the sensible framing is mechanistic plausibility, not demonstrated synergy. This is educational information about how the compounds work, not medical advice, and it is not a treatment for any condition. If you take medications or have a health condition, talk to your doctor before adding either.

How to choose between them

If your primary interest is muscle endurance, strength and exercise-related outcomes, urolithin A is the ingredient with the more directly relevant human muscle data to date, and it is the one SOMA HEALTH makes. If you are drawn specifically to the NAD+ decline hypothesis and the sirtuin and DNA-repair angle, an NR or NMN product is the category built around that idea. Consider your goal, the dose actually used in studies, third-party testing, and format. For urolithin A specifically, the clinically studied range is 500 to 1,000 mg per day, which you can explore further in our notes on urolithin A dosage, and our comparison of the best 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. This guide is educational and is not a substitute for advice from a qualified healthcare provider.