How to read a peptide lab report

A peptide lab report — most suppliers call it a COA, certificate of analysis — is the only thing standing between you and "trust me." It's also the document most people skim and most suppliers half-ass.

Here's how to actually read one.

What's on the page

A real report covers four things. They show up in different orders depending on which lab ran the tests, but the fields are always the same.

• HPLC purity — how much of what's in the vial is your peptide
• Mass spectrometry — whether it's the right molecule
• Endotoxin — bacterial contamination
• Sterility — whether anything's growing in there

If any of those four are missing, the report is incomplete. That's not me being precious — it's the bar that any reputable third-party lab will hit by default.

HPLC purity

HPLC separates whatever's in the vial by chemical behavior and gives you a chromatogram — a series of peaks. The big one should be your peptide. The little ones are impurities: leftover solvents, salts from synthesis, or truncated chains where the peptide didn't finish assembling.

The purity number is just math on that chart. Area under the main peak divided by area under all the peaks. So "96.4%" means 96.4% of the dry powder is the target peptide.

A few things people get wrong:

The number is meaningless without identity. A 99% pure sample of the wrong molecule reads the same as a 99% pure sample of the right one. You need mass spec to close the loop.

And "above 95%" is the floor, not the ceiling. We don't ship anything below it, and most credible suppliers don't either.

Mass spec — the identity check

Mass spec weighs molecules. The report gives you two numbers side by side: what the lab measured, and what was expected.

For BPC-157, expected is 1419.55 Da. A clean report will look like:

Observed: 1419.5 Da · Expected: 1419.55 Da

Match within a Dalton or so and you're fine. Off by more than that, you don't have what you ordered.

This is the field that catches the most fraud. Anyone can dilute a generic peptide and report 99% purity. Faking a mass spec readout is harder, and a lab that's actually doing the test will publish the chromatogram alongside the number.

Endotoxin and sterility

Endotoxins are fragments shed by gram-negative bacteria. Even trace amounts mess with cell-based work. The unit is EU/mg, lower is better, and < 0.5 EU/mg is the number you want to see.

Sterility is binary: passed or failed. Failed means microbial growth showed up when the sample was cultured. Almost every report you'll see says passed — but check anyway, because the ones that don't are the ones that matter.

The part most suppliers fudge: provenance

This is where transparency falls apart in this space. A PDF posted on a product page tells you a batch was tested. It doesn't tell you that the vial in front of you came from that batch.

What to look for on the sticker:

• A unique code per vial — UUID, batch ID, or a QR
• A URL that resolves on the supplier's own domain, not a Google Drive link or an Imgur image
• A named lab on the report (Janoshik, Anabolic Lab — anonymous reports are untested)
• A test date later than the vial's fill date

That last one trips up a lot of operators. If the report was generated before the vial was filled, you're looking at someone else's batch.

Every vial in our catalog carries its own QR — here's exactly how per-vial tracking works. Scan it and you land on pepuro.com/v/<uuid> — the live report for that exact vial. If a batch sells out, the link still resolves. The whole point of per-vial reports is being able to verify months later. (It's also the first thing to check when vetting any peptide supplier.)

What a real one looks like

Here's the report from a vial we shipped recently:

That's the format. You can scan one yourself on a sample vial page — same view a customer gets after ordering.

The shortcut

If you only have ten seconds with a report:

• Purity 95%+
• Mass spec within a Dalton of expected
• Endotoxin under 0.5 EU/mg
• A named lab
• A test date after the fill date

Miss any of those and the vial is untested in the only sense that matters.

Once a vial checks out, the next steps are practical: what "lyophilized" means and how to store it.