A Certificate of Analysis (COA) is the single most important document a research peptide supplier can provide. It is third-party proof of what is actually in the vial. This guide explains how to read one, what the numbers mean, and how to tell a legitimate COA from a fabricated one.
What a COA actually proves
A COA is a lab report tied to a specific production batch. A real one confirms two things: identity (the vial contains the peptide it claims to) and purity (how much of the contents is the target peptide versus impurities). If a vendor cannot produce a batch-specific COA, you have no verification of either.
The four things to check first
1. HPLC purity. High-Performance Liquid Chromatography separates the sample and measures how much is the target compound. Look for a stated purity percentage, typically 98% or higher for research-grade material, plus the chromatogram itself. A single dominant peak is what you want. Multiple large peaks indicate impurities.
2. Mass spectrometry (MS) identity. MS confirms the molecular weight of the peptide matches its known value. The observed mass on the COA should match the theoretical mass for that sequence. This is what confirms you have the right molecule, not just a pure unknown.
3. Batch or lot number. A real COA is tied to a lot number that matches the vial you received. A COA with no lot number, or one that never changes between batches, is a red flag.
4. The testing lab. Independent, third-party lab testing carries far more weight than in-house numbers a vendor cannot be audited on. The COA should identify the lab that ran the analysis.
How to spot a fake COA
- No batch or lot number, or a generic placeholder.
- A purity figure with no chromatogram to back it up.
- The same COA reused across every product or every batch.
- Blurry, cropped, or watermark-free images that look copied.
- No mass spec data, only a purity claim.
- A lab name that does not exist or cannot be verified.
If any of these appear, treat the purity claim as unverified.
Core Research Peptides COAs
Core Research Peptides publishes a third-party Certificate of Analysis for each product batch. Every COA includes HPLC purity with the chromatogram and mass spectrometry identity confirmation, tied to the batch lot. You can review the current COA on each individual product page before ordering.
All Core Research Peptides products are sold strictly for laboratory and research use only. They are not for human consumption.
Frequently asked questions
What purity should a research peptide be?
Research-grade peptides are typically 98% or higher by HPLC. The exact acceptable threshold depends on the application, but the chromatogram should show one clearly dominant peak.
Is a purity percentage enough on its own?
No. Purity tells you how much of the sample is a single compound, but not which compound. You need mass spectrometry identity data to confirm it is the correct peptide.
Can a COA be faked?
Yes. This is why batch-specific data, a named third-party lab, and a matching lot number matter. Reused or lot-less COAs are the most common form of fabrication.
How do I match a COA to my vial?
Compare the lot or batch number printed on the vial to the one on the COA. They should match exactly.
