Guide

How to read a Certificate of Analysis.

A COA is the only document that says anything specific about the vial in your hand. Here is how to tell a real one from a marketing PDF.

1. Is it lot-specific?

This is the first and most disqualifying check. A COA must reference a lot or batch number that matches the number printed on your vial. A "typical" or "representative" COA tells you what the supplier achieved once, not what is in your bottle.

2. Is there a chromatogram, or only a number?

A purity percentage without the chromatogram behind it is an assertion. The trace shows you peak shape, baseline, retention time and — critically — what else is in the sample. A single sharp peak on a flat baseline looks very different from a main peak sitting on a cluster of small impurity peaks that happen to sum under 1%.

Check that the axes are labelled, that the integration is visible, and that the method (column, gradient, detection wavelength) is stated. Purity figures are only comparable between suppliers when the method is.

3. Is identity confirmed independently of purity?

This is the check most suppliers skip, and it is the most important one. HPLC tells you how much of your sample is one substance. It does not tell you which substance. A synthesis that produced the wrong sequence, or a deletion sequence missing one residue, can still purify beautifully to 99%.

Mass spectrometry closes that gap by reporting observed mass-to-charge ratio against theoretical molecular weight. On a SpecPep COA you see both — BPC-157 with a theoretical MW of 1419.53 g/mol and an observed 1419.6 m/z.

4. Is contamination screened, with numbers?

Two screens matter for anything touching cells. Endotoxin (LAL) — bacterial lipopolysaccharide activates innate immune pathways at picogram concentrations, so in a cell-based assay undeclared LPS will produce a result, and it will not be the one you think. Look for a numeric EU/mg value, not the word "tested". Sterility — a named standard such as USP <71>, not the adjective "sterile".

5. Does the mass in the vial match the label?

Fill-weight verification confirms that a vial labelled 10 mg contains 10 mg. This sounds trivial and is routinely absent. SpecPep verifies fill weight to within ±0.5% of label claim and records it on the COA.

Separately, ask about net peptide content. Lyophilized peptides carry counterions (typically TFA or acetate) and residual water, so a vial can be 99% pure by HPLC and still be substantially less than 99% peptide by mass. The two numbers answer different questions and a thorough supplier gives you both.

6. Who ran the test?

A result generated in-house by the manufacturer is a self-report. Release testing performed by an ISO/IEC 17025 accredited third-party laboratory means the laboratory's competence, methods and equipment have themselves been audited against an international standard. Ask whether chain of custody documentation is available — a supplier who can produce it is telling you the sample tested is the sample shipped.

The checklist