How to read a certificate of analysis

A certificate of analysis (COA) is a lab report for one batch of a product. It tells you what was tested, how, by whom, and what the results were. For research peptides it is the main way to check that a vial contains what the label says, at the purity claimed.

Below we walk through a real certificate: our BPC-157 5 mg, batch BPC-2608-638, tested in September 2026.

1. Who tested it and when

At the top you’ll find the report number and the issue date, and somewhere on the certificate the testing laboratory and the person who signed it off. Our BPC-157 report is JLP-COA-26-4815, issued 11 September 2026, tested by an external UK laboratory and authorised by its Head of Analytical Chemistry.

What to check:

• A lab you can identify, or a result you can trace. Some testing labs, including ours, ask not to be named publicly. Then the report number, the signatory and the seller’s willingness to answer questions about a batch matter even more.
• A recent date. A certificate should be for the batch you’re buying, not a report from years ago.
• A report number and a signatory, so the result can be traced and queried.

2. Which sample and which batch

• Lot / batch number: BPC-2608-638. This should match the batch number on your vial. If a seller can’t tell you which batch your vial came from, the certificate doesn’t prove much.
• Sample ID and date received / date tested: the lab’s own tracking. Ours was received on 5 September and tested on 7 September 2026.
• Stated quantity and container: what the vial is supposed to hold (5 mg per vial, 3 mL crimp-sealed glass vial).

3. What the compound is

• CAS number: a unique registry number for a chemical substance. BPC-157’s is 137525-51-0.
• Molecular formula and molecular weight: C₆₂H₉₈N₁₆O₂₂, 1419.5 g/mol. The weight matters because it is what the mass test (below) looks for.
• Sequence: for a peptide, the exact chain of amino acids. BPC-157 is 15 amino acids long.
• Form: lyophilised (freeze-dried) powder.

4. How it was tested: HPLC and LC-MS

The method line on our certificate reads HPLC-UV / LC-MS. These are two different tests, and a good certificate uses both.

HPLC (high-performance liquid chromatography) pushes the sample through a column that separates it into its components. A UV detector records each component as a peak on a graph. Purity is the main peak’s share of the total: 99.790% means 99.790% of what the detector saw was the target peptide, and the rest was impurities, typically fragments or by-products of synthesis.

LC-MS (liquid chromatography–mass spectrometry) weighs the molecules. It confirms identity: that the main peak really has the molecular weight of BPC-157, not just that something in the vial is pure.

Why both? Purity alone can’t tell you what is pure. Identity alone can’t tell you how much of the vial is something else.

5. The results

• Quantity: 5.12 mg measured against 5 mg stated. A small overfill is normal; a big shortfall isn’t.
• Purity: 99.790%.
• Conclusion: “complies with the stated specifications”. Note the standard wording: results relate only to the sample tested.

Blends list a measured amount for each component and one overall purity. Our Glow Blend certificate shows GHK-Cu 50.49 mg, BPC-157 10.17 mg and TB-500 10.53 mg, at 99.127% purity.

Reagents are tested differently. Bacteriostatic water isn’t a peptide, so its certificate checks preservative content (benzyl alcohol 0.89%), sterility (pass) and endotoxins (under 0.25 EU/mL) instead of purity.

6. Warning signs of a certificate you can’t trust

• No report number or signatory, so nothing can be traced
• No batch number, or one that doesn’t match your vial
• No method stated, or purity with no identity test
• Purity of exactly 100%. Real analytical results are rarely that round.
• The same report used for several products or batches
• A date long before the batch could have been made
• A seller who won’t send the certificate before you buy

Where to find JLP certificates

Every compound on our site has its certificate on its product page (look for “View COA”), and a copy comes with every order. All 35 of our current certificates for peptides and other research compounds show purity between 99.1% and 99.9% by HPLC, with identity confirmed by LC-MS.

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