The finding, in one paragraph
An independent lab in Germany assayed DoNotAge's Pure NMN capsules and reported around 99% purity, with the measured content slightly above the labelled dose. That is the strongest single piece of physical, non-marketing evidence we came across for any product in this comparison, and it is one of the reasons DoNotAge's NMN scores where it does on our page.
Why this is unusual in the category
Most longevity supplement pages tell you they are "tested by independent lab". Very few link the actual certificate of analysis. When we asked ourselves how many products in the four brands we cover here (DoNotAge, IM8, NOVOS, Thorne) have a physical, independent lab result that a reader can read for themselves, the answer was: this one.
Every brand says "tested by independent lab". This is the only brand where an independent lab published the number.
What it does prove
- The capsule contains what the label claims it contains, at the labelled dose or slightly higher.
- There is no meaningful contamination or filler substituting for NMN in the batch tested.
- DoNotAge's cold-chain and manufacturing process, for that batch, held up to independent analysis.
What it does not prove
- It does not prove that NMN taken orally raises meaningful markers of biological age in humans. That is an ingredient question, not a product question, and the ingredient-level answer is still "promising but not settled".
- It does not prove other batches meet the same purity. Batch-to-batch variance is a genuine industry issue.
- It does not exempt DoNotAge from the regulatory picture. NMN is currently an FDA-excluded ingredient in the U.S. and has an unresolved novel-food status in several EU member states.
How we use it in scoring
The German lab report lives in Tier A of DoNotAge Pure NMN's external-source hierarchy. It contributes to the product's Transparency component, which is 20% of the overall score, because a linkable independent lab result is the strongest transparency signal we can find. It does not affect the Dose × Evidence component, because that measures the underlying clinical literature on NMN as an ingredient, not the physical purity of any single brand's capsule.