Research Guide · 6 min read · Updated 2026-08-01
How to Read a Peptide Certificate of Analysis (COA)
A Certificate of Analysis is the only thing separating a verified peptide from a promise. Yet most buyers never learn to read one. This guide explains each section of a peptide COA, what good results look like, and the red flags that should send you to a different supplier.
Section 1: HPLC Purity
High-Performance Liquid Chromatography separates your peptide from impurities and produces a chromatogram with peaks. The main peak should dominate; the reported purity (area percentage) should be ≥99% for research-grade material. A COA showing 98.1% or "≥98%" is telling you the batch failed a stricter standard.
Section 2: Mass Spectrometry Identity
MS confirms the peptide is actually what the label says. The measured molecular weight must match the theoretical value stated for that exact compound and batch — for example, BPC-157 at 1419.53 g/mol. A COA without MS identity confirmation only tells you something is 99% pure — not 99% of what.
Section 3: Batch Number and Date
The COA must carry a batch number that matches your vial label, plus an analysis date. A COA with no batch number — or one recycled across months of orders — is marketing, not documentation.
Red Flags to Watch For
COAs only available "after purchase". Stock COAs with no batch number. Purity quoted without a chromatogram. No MS data. In-house-only testing with no independent verification. Any one of these should trigger questions; two or more should end the conversation.
Noxptide supplies batch-specific COAs with every order and sends current batch documentation before purchase on request — the standard this guide argues for.
