The Certificate of Analysis (COA) is the most important quality document a research peptide vendor can provide. It is the primary means by which researchers can verify that the compound they are purchasing matches the specifications claimed by the vendor. Yet many researchers — particularly those new to peptide research — are uncertain how to read a COA or what to look for.
This guide explains what a legitimate peptide COA should contain, how to interpret the key data points, and how to identify documentation that may be unreliable or fraudulent.
Why the COA Matters
Research peptides are not regulated pharmaceutical products. There is no government agency that inspects peptide manufacturers or verifies their quality claims before products reach researchers. The COA from a third-party laboratory is the only independent verification that a vendor’s quality claims are accurate.
A researcher who uses peptide of unknown or substandard purity is introducing an uncontrolled variable into their work. If a product labeled as 99% pure BPC-157 is actually 80% pure — or contains a different peptide entirely — any results obtained from that research are unreliable and cannot be compared to published literature.
The Two Core Tests: HPLC and Mass Spectrometry
A complete peptide COA should include results from at least two analytical methods:
High-Performance Liquid Chromatography (HPLC)
HPLC is the standard method for measuring peptide purity. The test works by passing the peptide sample through a column that separates compounds based on their chemical properties. The output is a chromatogram — a graph showing peaks that represent different compounds in the sample.
How to read an HPLC chromatogram: The main peak represents the target peptide. Its area as a percentage of total peak area is the purity percentage. A purity of ≥99% means the main peak accounts for 99% or more of total detected compounds. Multiple significant peaks indicate the presence of impurities, synthesis byproducts, or degradation products. A single sharp, dominant peak with minimal background is the ideal result.
The HPLC report should include the chromatogram image, the purity percentage, the retention time of the main peak, and the method parameters (column type, mobile phase, gradient). A COA that only states a purity number without the chromatogram data is not verifiable.
Mass Spectrometry (MS)
Mass spectrometry confirms the identity of the peptide by measuring its molecular weight. Every peptide has a specific, calculable molecular weight based on its amino acid sequence. Mass spectrometry verifies that the compound in the sample matches the expected molecular weight of the target peptide.
How to read a mass spectrometry result: The report will show the observed molecular weight (m/z value) of the compound. This should match the theoretical molecular weight of the peptide within a small margin of error (typically ±0.1 Da or less). If the observed molecular weight does not match the theoretical weight, the sample either contains the wrong peptide or has been degraded.
Together, HPLC and mass spectrometry provide two independent lines of evidence: HPLC confirms purity, and mass spectrometry confirms identity. Both are required for a complete quality verification.
What a Complete COA Should Include
| COA Element | What to Look For | Red Flag |
|---|---|---|
| Testing laboratory name | Named, verifiable third-party lab | No lab name, or “internal testing” |
| Test date | Recent, batch-specific date | Old date, or no date |
| Lot/batch number | Specific number matching your product | Generic or missing |
| HPLC chromatogram | Clear graph with purity % ≥99% | Purity number only, no graph |
| Mass spectrometry result | Observed MW matches theoretical MW | Missing, or significant deviation |
| Peptide name and sequence | Correct name and amino acid sequence | Vague product description |
| Purity percentage | ≥99% for research-grade | Below 98%, or unspecified |
How to Verify a COA Is Legitimate
The most important step in verifying a COA is confirming that the testing laboratory exists and is accredited. A vendor can fabricate a COA document, but they cannot fabricate a real laboratory. Before relying on a COA, take these steps:
1. Search for the laboratory online. A legitimate analytical laboratory will have a website, a physical address, and contact information. If a Google search for the laboratory name returns no results, the COA may be fraudulent.
2. Check for accreditation. Reputable laboratories hold accreditation from organizations such as ISO/IEC 17025 or A2LA. Accreditation means the laboratory’s methods have been independently verified.
3. Confirm the batch number matches your product. Ask the vendor to confirm which lot number your specific order came from, and verify that the COA you are reviewing corresponds to that lot. A COA that applies to no specific batch is not meaningful.
4. Compare the molecular weight. Look up the theoretical molecular weight of the peptide you are purchasing (available from databases such as PubChem) and compare it to the mass spectrometry result on the COA. They should match closely.
Common COA Red Flags
Generic COAs. Some vendors display a single COA for a product that applies to no specific batch. This means the COA may be months or years old and does not reflect the quality of the product you are receiving.
Purity stated without HPLC data. Any vendor can claim 99% purity. Without the HPLC chromatogram to support it, the claim is unverifiable.
No mass spectrometry. HPLC alone cannot confirm that the compound is the correct peptide — it only measures purity. Without mass spectrometry, there is no independent confirmation of identity.
Unverifiable laboratory. If you cannot find the testing laboratory online or confirm it is a real, operating facility, the COA should not be trusted.
COA available only after purchase. Reputable vendors make COAs available before purchase. A vendor who withholds COA documentation until after you have paid has no incentive to maintain quality standards.
Wellington Reserve’s Documentation Standards
Wellington Reserve provides batch-specific COAs for every product in our catalog, generated by independent third-party laboratories. Each COA includes full HPLC chromatogram data, mass spectrometry results, purity percentage, lot number, and test date. COAs are available for review before purchase at wellingtoncompounds.com.
We believe transparency in documentation is not optional — it is the baseline standard for any vendor serving the research community.
Important Research Disclaimer
All peptides sold by Wellington Reserve are for research purposes only. They are not intended for human consumption and are not approved by the FDA for therapeutic use.
Wellington Reserve supplies research-grade peptides with ≥99% purity, independently tested and fully documented. View our COA library at wellingtoncompounds.com.