Eight NMN products, one lab

In December 2025 we purchased, at standard retail prices, eight nicotinamide mononucleotide (NMN) products from the eight largest US-market sellers. We anonymised the samples, sent them to an ISO-17025 accredited contract laboratory in Basel, and asked for two readouts: identity confirmation by HPLC against a USP-grade NMN reference standard, and quantitation of NMN content per stated serving by validated UV-detection method.

Headline numbers

Two of the eight products failed identity testing — meaning the contract lab could not confirm that the major peak in the assay corresponded to NMN. Three additional products passed identity but failed quantitation by more than the USP-allowed 90–110% of label claim. Three products met both identity and quantitation. The failure rate of 5 in 8 (62.5%) is consistent with the failure rates reported by independent assay desks in the broader supplement category, but is on the high end for a category that markets itself on biochemical precision.

Why this happens

NMN is unstable. It hydrolyses to nicotinamide and ribose-5-phosphate in the presence of moisture and heat. The compound that arrives at the formulator's loading dock is not necessarily the compound that exits the bottle six months later, particularly in capsules formulated without a desiccant or in bottles shipped through warm warehouses in the US south. A product that passed identity at the point of manufacture can fail identity at the point of sale.

There is also an upstream problem. Pharmaceutical-grade NMN is expensive; food-grade NMN is cheaper; mislabelled nicotinamide riboside (NR) is cheaper still. We did not detect any NR substitution in this round, but we have detected it in two of the last four rounds. We will continue to test.

What we are publishing and what we are not

We are not publishing the brand names of the failing products. Two reasons. First, we have a single-round sample size of n=1 per brand; it is statistically inappropriate to brand-name a product on a single failed batch. Second, the legal landscape around naming a failing supplement is hostile in a way that consumes resources we would rather spend on more testing. We will publish brand names only when a brand fails three independent rounds of testing across at least two purchase batches.

We are publishing the methodology, the failure rate, the broad failure modes, and the names of the three brands that passed both identity and quantitation. Those three brands are listed on the Vitaei Index page for NMN, ranked by analytical performance and unit price. We have no commercial relationship with any of them.

Practical guidance

• Buy NMN in opaque, desiccated, sealed packaging. Avoid clear bottles.
• Buy from a manufacturer that publishes a Certificate of Analysis (CoA) per batch, with the lot number on the bottle matched to a CoA on the manufacturer's website. Do not accept a generic 'representative' CoA.
• Refrigerate the bottle once opened. NMN degrades roughly 5x faster at room temperature than at 4°C.
• Replace the bottle every 90 days, even if servings remain. Discard the remaining capsules.
• If you cannot satisfy these conditions, consider switching to nicotinamide riboside, which is more stable in the bottle, even though it is biochemically one step further from the NAD+ molecule.