From Testing the amount of nicotinamide mononucleotide and urolithin A as compared to the label claim. The white numbers are the code numbers for the (unidentified) NMN and UA products purchased online and from pharmacies.
Half of the NMN You Buy Isn’t Really There: The Longevity Supplement Quality Scandal
Scientists at the National University of Singapore bought 18 nicotinamide mononucleotide (NMN) and 5 Urolithin A (UA) supplements from online stores, pharmacies, and manufacturers, then used a validated laboratory method (mass spectrometry) to measure the true active-ingredient content. The results were poor. Product content ranged from 28.6 percent more than the label claimed all the way down to nothing detectable at all (minus 100 percent). Most products contained less than advertised, and two NMN capsules and one UA product contained no measurable active ingredient despite what the label promised. The take-home is uncomfortable but simple. The geroprotective supplement market has a serious quality-control problem, and the number on the bottle is not a reliable guide to what you are actually swallowing.
The longevity field has spent a decade arguing about whether molecules like NMN and Urolithin A can slow aging. This study asks a more basic and more awkward question. Before we debate whether these compounds work, are consumers even getting the compounds at all?
The answer, disturbingly often, is no. A team led by Elena Sandalova and Andrea Maier at the National University of Singapore, alongside longevity researcher Brian Kennedy, assembled 23 real products, blinded and randomly coded them, and put each through high-performance liquid chromatography coupled to triple quadrupole mass spectrometry. This is the analytical gold standard, sensitive and specific enough to quantify tiny amounts of a molecule. The team also validated recovery, precision, accuracy, and matrix effects, so the finding cannot be waved away as a lab artifact.
Across the 18 NMN products, the measured content diverged wildly from the label. Some were close. Several were not. Two capsules contained no detectable NMN whatsoever. One so-called NMN powder held barely 13 percent of what it claimed. On average the NMN products fell short of their labels by roughly a quarter of the stated dose. The Urolithin A products were somewhat better but still inconsistent, with one softgel overshooting its label by nearly 30 percent and another running 15 percent short.
Why does this happen? The authors point to a regulatory vacuum. Under the US Dietary Supplement Health and Education Act, supplements are not tested for label accuracy before sale. Safety authorities check only for banned substances, not for whether the active ingredient is present in the promised amount. Some shortfalls likely reflect genuine chemical degradation over time, since NMN is unstable and hard to manufacture. Others suggest the ingredient was simply never added in full. A few products contained more than labeled, a practice called overage, where manufacturers deliberately overfill to survive shelf-life breakdown.
The bigger idea reaches beyond any single molecule. It exposes a structural weakness at the heart of the consumer longevity economy. Clinical trials that show a benefit almost always test a single, pure, correctly dosed compound. If the bottle in your cabinet does not match that dose, the trial evidence may not apply to you at all. The authors call for coordinated action between professional societies, industry, and regulators. Until that happens, the burden of verification falls on the buyer.
