Read a COA without trusting it blindly

Does the COA name the exact product and amino-acid sequence you ordered, and does it match the vial label?

A COA for a different peptide, or with no sequence stated, does not describe what is in your vial. A name with no sequence cannot be cross-checked against the compound you intended to buy.

Is there a lot or batch number on the COA, and does it match the lot printed on the vial you received?

A COA is only evidence about the lot it names. If the vial has no lot, or the numbers differ, the document is not about your vial — it is about some other batch.

What is the test date, and is it close to when this batch was made rather than years old?

An old test date can mean the COA was reused across newer production runs. Testing predates and does not cover material made after it.

Is the testing lab named, and is it an independent third party rather than the vendor itself?

An unnamed lab, or testing done in-house by the seller, removes the independence the COA is supposed to provide. You cannot weigh a result you cannot trace to a lab.

If you have more than one lab report for the same lot, do the product, lot, observed mass, purity, and peptide-content results agree rather than conflict?

Multiple reports are not additive when they disagree. A vendor-supplied COA and a separate lab report for the same lot must be read as separate evidence; unresolved purity, mass, or content conflicts mean the documentation does not describe one coherent batch.

Does the COA carry a report, task, or order number that the lab can use to confirm it?

Without a traceable report number there is no way for the lab to confirm the document is one it issued, and no way for you to detect a fabricated or altered PDF.

Can you verify this report directly with the lab — a working QR code or a lookup on the lab’s own site?

A COA confirmed only by the vendor is confirmed by the party with the incentive to pass. Verification has to route to the lab, not back to the seller.

Is there an ISO/IEC 17025 accreditation signal for the lab, with a scope you can check?

An accreditation claim with no body or certificate number is unverifiable. Accreditation also applies only within a stated scope, so a logo alone does not tell you the relevant method is covered.

Is there an HPLC purity result with the actual chromatogram shown, not just a single percentage?

A bare purity number with no chromatogram cannot be checked for integration, baseline, or impurity peaks. A number alone is an assertion, not data.

Is identity confirmed by mass spectrometry, with the observed mass against the expected mass?

Purity tells you how much of the main peak there is; it does not tell you the main peak is the right molecule. Without MS identity, the COA does not establish the peptide is what it claims.

Does the COA distinguish gross peptide content from net peptide content (mass spec / acetate / water adjusted)?

Net peptide content is usually lower than the labeled gross mass. If only gross mass is stated, the dose you calculate from the label can be higher than the peptide actually delivered.

For an injectable, is there an endotoxin (bacterial pyrogen) result within an acceptable limit?

Endotoxin survives sterilization and causes systemic reactions when injected. A missing or out-of-limit endotoxin result is a direct injection-safety gap, not a paperwork detail.

For an injectable, is there a sterility result for the tested lot?

A sterility result describes the tested sample only. Its absence means the tested lot was never shown to be free of viable organisms; its presence still says nothing about the vial you hold.

Where applicable, is there a heavy-metals result within limits?

Heavy-metal contamination can enter from synthesis and reagents and is not removed by filtration. A missing result leaves a known contamination route untested.

Where applicable, are residual solvents (e.g. TFA, acetonitrile) reported within limits?

Synthesis and purification leave solvent residues. An unreported residual-solvent panel leaves another known contamination route untested.

The COA has no lot or batch number at all.

A COA with no batch cannot be tied to any specific production run, so it is evidence about nothing in particular.

The lot on the vial does not match the lot on the COA.

You are holding a different batch from the one that was tested. The document does not describe your vial.

The same COA (same lot, same date) is shown for multiple products or keeps reappearing across batches.

One reused report cannot cover material it was never run against. It signals testing is not done per batch.

A vendor-supplied COA and a separate lab report for the same lot disagree on identity, observed mass, purity, or peptide content.

Same-lot reports that conflict mean at least one report, sample, or lot claim is wrong. Protoche cannot choose a winning lab or average the results, so the documentation stays unresolved.

Purity is a suspiciously clean number like exactly 99% or 100% with no chromatogram.

Real HPLC results are rarely perfectly round and are reported with the chromatogram. A clean number with no data is an assertion, and a common sign of a fabricated COA.

The vendor will not give a report or task number, or will not say which lab ran it.

Refusing the information needed to verify the report independently removes the only thing that makes a COA meaningful.

The named lab cannot be independently found, or has no real verification path.

A lab that does not exist outside the COA cannot have tested anything. The independence the document implies is not real.

A COA is only produced after you have paid, never available before.

A document you cannot see until after committing money cannot inform the decision it is supposed to inform.

A named lab is cited but no raw data (chromatogram, spectrum) is shown — only a summary line.

Citing a lab without the underlying data means the claim cannot be checked even though it looks sourced.