How to Verify NMN Purity: A Buyer Checklist

Why Purity Verification Matters

The NMN market has grown faster than regulatory oversight. A COA showing 98% NMN can be generated by many different analytical methods — some rigorous, some not.

The Essential COA Checklist

1. HPLC Assay (Primary Purity)

The assay percentage should be determined by HPLC, not UV spectrophotometry alone. Look for: column type, mobile phase composition, reference standard, and run date. A COA listing only "Assay ≥98%" without the method is a red flag.

2. Water Content (Karl Fischer)

NMN is hygroscopic. Water content above 2.0% indicates improper drying or packaging. Acceptable: ≤1.0% for pharmaceutical grade.

3. Specific Rotation

NMN is a chiral molecule. Confirm you have the correct β-isomer. Acceptable range: [α]D²⁵ = +40° to +46°.

4. Heavy Metals

Must specify individual limits for Pb (≤0.5 ppm), As (≤0.5 ppm), Hg (≤0.1 ppm), Cd (≤0.5 ppm) per USP <232>/<233> or EP 2.4.20.

5. Residual Solvents

Common solvents to check: ethanol, methanol, acetonitrile, isopropanol. ICH Q3C Class 2 limits apply for pharmaceutical applications.

6. Microbiology (oral products)

Total Aerobic Count ≤1000 CFU/g, Yeast & Mold ≤100 CFU/g, absence of E. coli and Salmonella per USP <61>/<62>.

Red Flags

• COA from manufacturer internal lab only, no third-party confirmation
• Missing test dates or lot numbers not matching your shipment
• Purity listed as ≥99% but no HPLC chromatogram available
• No specific rotation value
• Residual solvent section completely absent

What PathGene Provides

Every lot ships with a full COA including HPLC chromatogram, Karl Fischer water content, specific rotation, ICP-MS heavy metals, residual solvents by GC-HS, and full microbiology panel — all tested by ISO 17025-accredited third-party labs. Download a sample COA here.