Urolithin A vs NMN: Which Should You Take?

Urolithin A and NMN are two of the most talked-about compounds in cellular health, and they are often framed as rivals. They are not really competitors — they work on different parts of the same problem. Understanding the mechanisms makes the choice much clearer.

Same goal, different machinery

Both compounds are studied in the context of the mitochondria — the structures inside your cells that turn food and oxygen into usable energy. Mitochondrial function tends to decline with age, and both urolithin A and NMN aim to support it. But they approach the mitochondria from opposite directions. One is about quality control; the other is about fuel supply. Knowing which is which is the key to the whole comparison.

How urolithin A works: mitochondrial quality control

Urolithin A is a gut postbiotic — your microbiome makes it from ellagitannins found in pomegranate, walnuts and berries, although only some people convert it efficiently (more in our urolithin A guide). Its central mechanism is supporting mitophagy: the cell’s process for identifying worn-out, underperforming mitochondria and recycling them so healthier ones can take over. Think of it as maintenance rather than fuel — clearing out the damaged units instead of pouring in more energy. Our explainer on mitophagy walks through this in detail.

The human evidence, organised by strength:

Established human findings

Andreux et al. (2019, Nature Metabolism) ran the first-in-human study, showing urolithin A was safe and well tolerated up to 1,000 mg/day and produced a measurable mitochondrial gene-expression signature. Singh et al. (2022, Cell Reports Medicine) tested 500 and 1,000 mg arms in middle-aged adults over four months and reported effects on muscle strength and exercise performance. The Liu/D’Amico team (2022, JAMA Network Open) found improved muscle endurance — more contractions before fatigue — in older adults.

Newer human findings

A 2024 Journal of the International Society of Sports Nutrition RCT in resistance-trained men looked at endurance and recovery markers over eight weeks. A 2025 Nature Aging RCT reported support for immune-cell mitochondrial health in midlife adults over roughly 28 days. A 2024 systematic review in Ageing Research Reviews is candid that the human evidence, while promising, is still emerging — the trials are relatively short and modest in size.

Preclinical origins

The foundational work — Ryu et al. (2016, Nature Medicine) — was in worms and rodents, where urolithin A improved mitophagy and muscle function. That is animal and cell research, not human proof, and it is best read as the origin of the hypothesis the human trials have since begun testing.

How NMN works: refilling the NAD+ tank

NMN (nicotinamide mononucleotide) takes a different route. It is a direct precursor to NAD+, a coenzyme every cell uses to run energy metabolism and to power repair enzymes such as the sirtuins. NAD+ levels fall with age, and the logic of NMN supplementation is straightforward: supply the building block, and the cell can top up its NAD+ pool. Where urolithin A is about clearing out damaged mitochondria, NMN is about keeping the energy-and-repair currency stocked. It is fuel-supply and signalling, not quality control.

The human evidence for NMN is also still maturing. Clinical trials to date have generally focused on safety and on early markers — areas such as insulin sensitivity, aerobic capacity and physical measures — with results that are encouraging but not yet definitive, and trial sizes that remain modest. As with urolithin A, much of the deeper mechanistic work sits in animal models.

One practical wrinkle worth knowing: the regulatory status of NMN as a dietary supplement has been unsettled in the United States, because it has been examined in the context of drug investigation. That situation has shifted more than once, so availability and labelling can vary — check the current status where you buy. This is a regulatory point, not a safety verdict.

Head to head

Mechanism. Urolithin A supports mitophagy — recycling damaged mitochondria. NMN supports NAD+ levels — the coenzyme behind energy metabolism and repair signalling. Different jobs.

Source. Urolithin A is a gut-derived postbiotic from dietary polyphenols. NMN is a nucleotide the body also makes internally as part of NAD+ recycling.

Human evidence. Both are early-stage. Urolithin A has a growing set of RCTs pointing specifically at muscle endurance, strength and mitochondrial and immune-cell measures. NMN has human safety data and early metabolic and performance signals. Neither has long, large, definitive outcome trials yet — honesty matters here.

Convertibility. Urolithin A production from food is a lottery — many people convert poorly — which is a strong argument for a standardised dose. NMN is delivered directly as the molecule.

Do they compete — or complement?

Because they act on different mechanisms — quality control versus fuel supply — they are not mutually exclusive in principle, and some people use both. There is no requirement to choose one as if the other were wrong. That said, we would offer two honest caveats. First, there is no large body of human research on taking the two together, so any combined use is reasoning from mechanism, not from trial data. Second, more compounds is not automatically better — it is sensible to start with one, at a studied dose, and understand how you respond before stacking. If you do consider combining supplements, especially alongside medication, that is a conversation to have with your doctor.

How to choose

Match the tool to the goal. If your interest is squarely in the mitophagy pathway — clearing worn mitochondria to support muscle endurance, strength and cellular health — urolithin A has the more directly relevant human trials for those specific outcomes, and it sidesteps the conversion problem when taken as a standardised supplement. If your interest is broad NAD+ support, NMN is built for that role, with the regulatory caveat above. Many people also value that urolithin A has been studied at a clearly defined dose range, which makes it easy to match what the research used. To go deeper on that, see our dosage guide, the best urolithin A gummies roundup, and our benefits overview.

A scope note, because energy, metabolism and muscle are health-adjacent topics: both compounds are studied to support normal cellular function, not to diagnose, treat or cure any disease. Neither is a treatment. If you have a medical condition or take medication, talk with your doctor before starting either one.

*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.