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How to read a peptide COA
A certificate of analysis is the only real evidence of what's in a research peptide vial. Here's what each part means and how to tell a useful COA from a decoration.
Disclosure: this site is published by Bluum LLC, the company behind Bluum Peptides, our top pick. Use the checklist below to judge any supplier, including us.
The six things every peptide COA should show
| Field | Why it matters |
|---|---|
| Lot / batch number | Must match the label on your vial. No lot, no proof. |
| Testing lab and report number | Lets you confirm the report with the lab that issued it. |
| Test date | Shows the report is for a current batch, not one from years ago. |
| Identity (mass spec) | LC-MS or MALDI confirms the molecular mass matches the labeled peptide. |
| Purity (HPLC) | The share of the sample that is the target peptide. Research buyers usually want ≥98%. |
| Net content | How many milligrams are actually in the vial versus the label. |
Strong reports add endotoxin (LAL, USP <85>), sterility and heavy metals (ICP-MS).
HPLC purity vs mass spec identity
HPLC separates a sample into its components and measures the main peak as a percentage. It cannot tell you whether that main peak is the right molecule. Mass spectrometry weighs the molecule and confirms its identity. A COA with HPLC alone leaves the biggest question unanswered.
How to verify a COA in three steps
- Find the lot number on the vial label or order confirmation.
- Look it up in the supplier's report library. At Bluum, use the lab report lookup; each lot shows its report, test date, lab and results.
- Confirm with the lab. Search the report or accession number on the lab's website. Bluum's reports can be checked on FreedomDiagnosticsTesting.com or horizonanalytical.com.
Warning signs on a COA
- No lot number, or a lot that doesn't match your vial
- No lab name, or a lab you can't find
- Purity only, with no identity test
- Identical reports reused across products or years
- Round numbers like "99.9%" on everything, every batch
FAQ
What is a peptide COA?
A certificate of analysis is a lab report for one production lot. For research peptides it should show the lot number, the testing lab, the test date and results for identity, purity and often content and endotoxin.
Can a COA be faked?
Yes. That's why you should verify it with the issuing lab using the report or accession number, and make sure the lot number matches your vial.
What purity is good for a research peptide?
Most researchers want 98% or higher by HPLC, with identity confirmed by mass spectrometry.
Research use only. Research peptides are laboratory reagents for in vitro and analytical research. They are not drugs, supplements or cosmetics and are not for human or veterinary use. Nothing on this site is dosing or medical advice. Buyers must be 21+.
Check a real lot-specific peptide COA
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