How to Read a Peptide Certificate of Analysis (COA)

For laboratory research use only. Not for human or veterinary use.

A Certificate of Analysis is the only objective evidence that a research peptide is what its label claims. Anyone can print "99% purity" on a vial. A COA is a laboratory document that either supports that claim or doesn't. Here's how to read one properly — and how to spot the ones that aren't worth the paper.

What a COA is#

A COA is the analytical report produced when a batch of material is tested. It records what the compound is, how pure it is, what method was used to determine that, and which specific batch was tested. It is produced per batch — not per product.

The eight things to check#

1. Batch or lot number. This is the most important field, and the one fake COAs get wrong. The batch number on the certificate must match the batch your supplier names for your order. A COA that doesn't reference a specific batch is decoration, not documentation.

2. Product identity. The compound name and molecular formula should be stated. Cross-check the molecular weight against the published value for that peptide — mismatches indicate either an error or a different compound.

3. Purity figure. Usually expressed as a percentage. For research-grade peptides, 98–99%+ is the range to expect from a serious supplier.

4. The method used. This is what separates real data from marketing. Look for HPLC (High-Performance Liquid Chromatography) for purity, and ideally MS (Mass Spectrometry) for identity confirmation. A purity claim with no stated method is meaningless.

5. The chromatogram. A genuine HPLC report includes the trace itself — a graph with a dominant peak representing your compound. The area under that peak is where the purity percentage comes from. If a COA shows only a number and no chromatogram, ask why.

6. Test date. Recent testing matters. A certificate from years ago tells you about material that may no longer exist.

7. Who performed the analysis. The testing laboratory should be identified. Third-party testing carries more weight than self-reported figures.

8. The verification reference. Reputable laboratories issue each report with a unique key or reference that lets anyone retrieve that report from the lab directly. This is the field that makes the other seven checkable, because it is the only one you can confirm without the supplier’s involvement. A certificate with no verification reference asks you to take the supplier’s word for the document itself.

Step by step, with a worked example you can run against our own certificates: how to verify a peptide COA.

Warning signs#

• No batch number, or a batch number that does not match the vial supplied
• No method stated — just a percentage
• No chromatogram — the underlying data is missing
• Identical COAs issued for every batch (a real COA is unique to a batch)
• Different certificates sharing one verification reference. Harder to spot than a duplicated COA and more common: several documents with different compounds, batch numbers and dates, all carrying the same key. Each looks fine on its own. Compared side by side, at least one has been edited after issue. Check the reference is unique across every certificate a supplier shows you
• Purity claims above 99.9% for complex peptides — implausibly perfect figures are a red flag
• Suppliers who won't provide one — this tells you everything

Our own certificates#

Our certificates of analysis are being re-checked, and we are not publishing them or making testing claims until that is finished. Ask us about the documentation for a specific batch before you order, and run all eight checks above against anything we send you.

Why identity matters as much as purity#

Purity answers "how much of this vial is the compound?" Identity answers "is it the right compound at all?" A vial can be 99% pure and still be 99% of the wrong molecule. That's why mass spectrometry — which confirms molecular weight — belongs alongside HPLC on a complete certificate.

Chromatography alone cannot close the question. HPLC tells you the relative abundance of each peak; it does not tell you what each peak is. Two compounds can co-elute and appear as one peak, and a trace can look clean while the underlying material is wrong. Mass spectrometry measures mass-to-charge ratio, so it answers the identity question the chromatogram cannot. HPLC establishes purity, MS establishes identity, and a certificate quoting only one is answering half the question.

The simple test#

Ask any supplier: "Can I see the COA for the batch you'd be shipping me?"

A supplier with proper documentation sends it without hesitation. A supplier who deflects, delays, or sends a generic document is telling you what you need to know.

Our standard#

Our certificates of analysis are being re-checked, and we are not publishing them or making testing claims until that is finished. Ask about the documentation for the batch we would ship before you order.

Treat purity documentation as a filter rather than a bonus, with us as with anyone else.

Sources#

• ICH Q2(R2), Validation of Analytical Procedures — EMA/CHMP/ICH/82072/2006, adopted 14 December 2023. Checks 4 and 7, and the reason mass spectrometry belongs beside HPLC: where a single procedure cannot discriminate sufficiently, the guideline recommends “a combination of two or more procedures”, and says a confirming procedure should ideally apply a different measurement principle
• ANDAs for Certain Highly Purified Synthetic Peptide Drug Products That Refer to Listed Drugs of rDNA Origin — FDA guidance for industry, May 2021. Defines peptide-related impurities as sequences differing by insertion, deletion or modification of amino acids, asks that each be identified at 0.10% of the drug substance or above, and recommends orthogonal methods to establish primary sequence rather than one method alone
• Bachem — What does net peptide content mean? — Check 3. Net peptide content is the peptidic fraction relative to counter-ions and residual water, which is why a purity percentage is not a quantity and a certificate reporting both is worth more than one reporting either

Our certificates#

Our certificates of analysis are being re-checked, and until that is finished we are not publishing them or making testing claims. Ask us about the documentation for a specific batch before you order, and run the checks on this page against anything we send you. Products you can ask about include:

• BPC-157 — Body Protection Compound
• BPC-157 / TB-500 Blend — Pre-mixed blend (1:1)
• CJC-1295 (without DAC) + Ipamorelin — Pre-mixed GH research blend (5mg+5mg)
• CJC-1295 (without DAC) — GHRH analogue (no DAC)
• DSIP — Delta sleep-inducing peptide
• GHK-Cu — Copper tripeptide-1
• KLOW Blend — BPC-157 + GHK-Cu + TB-500 + KPV
• KPV — Tripeptide (Lys-Pro-Val)
• MOTS-c — Mitochondrial-derived peptide
• NAD+ — Nicotinamide adenine dinucleotide
• Selank — Heptapeptide (Thr-Lys-Pro-Arg-Pro-Gly-Pro)
• Semax — Heptapeptide, ACTH(4-7) analogue
• Sermorelin Acetate — GHRH (1-29) analogue
• SS-31 (Elamipretide) — Mitochondrial-targeted peptide
• GLOW Blend — BPC-157 + GHK-Cu + TB-500

Pioneer Research Peptides — UK supplier of research peptides for laboratory use. Ask about batch documentation before you order.

For laboratory research use only — not for human consumption. 18+.