A certificate of analysis should be evidence, not a sales document
A lab report can tell a buyer a great deal about a peptide. It can also leave out nearly everything the buyer needs to know.
Earlier this year I was sent a certificate showing 99.6% purity. It had a lab name, a test date, and a clean chromatogram. It had no lot number, and no report ID I could use to confirm the result with the lab.
The number may well have been right. I just had no way to know whether the report belonged to the material in front of me.
Certificates of analysis are now a standard part of how research peptide suppliers sell. Having one proves very little.
Three numbers
When I look at a certificate, I want three measurements: identity, purity, and content.
Identity answers the basic question: is this the compound it claims to be? Mass spectrometry checks whether the molecular mass matches the expected substance. It won't settle everything, but it catches the swaps.
Purity tells you how much of the detected material is the target compound. HPLC is the usual method. The percentage depends on the method, and it isn't the compound's percentage by weight.
Content is simpler: how much peptide is actually in the vial?
These are related, but one can't stand in for another. A sample can show high HPLC purity and still hold less peptide than the label says. A purity result can't establish identity on its own. And a certificate that confirms identity, but skips content, tells you nothing about whether the labelled amount is right.
None of this is news in pharmaceutical quality control. In research supply, a seller can still show a certificate with one or two of these numbers and let the buyer assume the rest.
Where the paperwork breaks
Often the trouble starts before anyone reads a result. One certificate names the compound and the lab, but leaves out the lot. Another gives a purity figure with no method. Some name a lab you can't actually reach.
Then, there's the question most buyers never ask: who gave you the document? If the seller is the only source, you're taking the seller's word that it's real and that it applies to what you bought. So, check the lab itself. Can you verify the certificate directly on its site? Does it hold ISO/IEC 17025 accreditation, or is it working towards it?
A certificate describes the sample that was tested. It doesn't automatically cover every vial later sold under the same name. Without a clear line from the tested sample to the manufacturing batch to the finished product, a buyer can't tell how far the results reach.
Testing bulk powder and testing filled vials are different things, too. Bulk testing can establish important properties of the material. It can't confirm what's in each finished vial, or sterility and endotoxins where those matter. A buyer should be able to see which stage was tested and which questions are still open.
Why the FDA meeting matters
The FDA's Pharmacy Compounding Advisory Committee met on 23rd and 24th July 2026, to review seven peptides for possible use in compounding under Section 503A: BPC-157, KPV, TB-500, MOTS-c, emideltide, Semax, and Epitalon. The agency's materials covered both the free-base and acetate forms of each. The committee recommended six of the seven. Emideltide was the exception.
Those recommendations are advisory. They don't put anything on the 503A bulks list, and changing that list takes further action by the FDA.
Still, the debate raises a question bigger than any single vote: what evidence should travel with peptide material as it moves through a supply chain?
Research-grade material and pharmaceutical ingredients sit under different rules, and a research certificate can't stand in for pharmaceutical documentation. But the analytical questions don't change with the market. Identity has to be established. Quantity has to be measured. Results have to match identifiable material. Whatever the FDA decides about individual peptides, anyone choosing a supplier still has to answer those three.
What a checkable certificate has
None of this needs a new testing system. Every certificate should name the material tested, the lot, and the lab that ran it.
Identity, purity, and content should be reported separately, each with a number and the method behind it. "Passed" means little without the result, the specification, and the acceptance criteria.
The certificate should also carry a unique report or sample ID, so a buyer can contact the lab directly and confirm the lab issued it and that it matches its records. A certificate the seller emails you is marketing until the lab confirms it.
Accreditation helps, but read it carefully. ISO/IEC 17025 covers the competence, impartiality, and consistent operation of testing labs. It doesn't mean every test a lab runs falls within its accredited scope, so check that the method you care about is covered.
Independent retesting goes a step further. A buyer can pay for a retest on a separately obtained sample and compare it with the supplier's paperwork. If the results differ, look at methods, sampling, and measurement uncertainty before drawing conclusions. One discrepancy doesn't prove the material is bad, and one passing result doesn't prove the whole shipment is good. The point is evidence traceable enough that a disagreement can be checked instead of argued about.
Who does what
Suppliers can post lot-level certificates where customers can find them, with report IDs anyone can verify without going through a salesperson.
Buyers can confirm important results with the issuing lab, read the methods and acceptance criteria, and find out whether testing covered bulk material or finished units.
Regulators weighing peptide bulk substances can ask whether today's documentation rules fit the risks of this supply chain, rather than assuming what works in one market carries over to another.
None of that replaces supplier qualification, manufacturing controls, or the extra testing pharmaceutical use requires. It does fix one avoidable weakness: not being able to tell a test result from one you can verify.
If you can't trace it back to the lab, the 99.6% at the top of the page is just a number.
About the author
Mike Vance is chief research officer at LabFirst Peptides, a research peptide supplier in Santa Ana, California, where he oversees independent lot testing and certificate publication.
