How to read a Certificate of Analysis (COA)
Purity, mass, endotoxins, sterility — what the numbers mean and what a pass/fail actually looks like across Janoshik, Freedom, ILS, and Vanguard reports.
The four numbers that matter
Purity (HPLC %): the main-peak area vs total peaks. Aim for ≥ 97%; 99%+ is common on quality sourcing.
Mass (MS): the observed molecular weight vs theoretical. Should match within a few Daltons.
Endotoxins (LAL, EU/mg or EU/vial): should be low — most reputable labs report < 5 EU/mg for parenteral-grade material.
Sterility (USP <71>): a pass/fail. A pass means no microbial growth in the tested media over the incubation period.
Lab-by-lab notes
Janoshik Analytical — the most widely referenced third-party. Reports include HPLC chromatogram, MS spectrum, and often an assay percentage.
Freedom Diagnostics — US-based, similar scope; sterility and endotoxin panels are separate line items.
ILS (Innovative Labs) — cleaner formatting, sometimes bundles peptide-content assay with purity.
Vanguard — expanded contaminant panels; watch for reported residual solvents and heavy metals.
Red flags
Purity reported without a chromatogram image.
No batch/lot number tying the COA to the actual vial.
Missing MS or a mass that doesn't match the compound's theoretical MW.
COA dated more than 12 months before the vial ship date.