How to Read a
Peptide COA

The report should clearly identify the sample it describes. The lot number on the COA should match the lot printed on the vial. A test from an unrelated or older batch tells you very little about the product in your hand.

• Peptide or compound name
• Vial strength or sample description
• Lot or batch number
• Testing and report dates
• Vendor or submitting customer, when disclosed
• Sealed production vial versus loose sample

Identity testing asks whether the sample actually contains the claimed compound. This is commonly evaluated with mass spectrometry: the measured molecular mass should align with the expected molecular mass of the peptide.

A purity result alone does not necessarily confirm identity. A sample can contain one highly pure substance and still be the wrong substance.

HPLC purity is commonly expressed as the percentage of the total detected chromatographic peak area attributed to the primary component. It does not necessarily mean that the peptide makes up that percentage of everything physically present in the vial.

That percentage does not automatically mean:

• The vial contains 99.2% of the labeled milligrams
• The vial is correctly filled
• The sample is sterile
• The product is free of endotoxins
• The peptide remained stable in transit
• Every substance in the vial was detected

Purity and peptide quantity are separate measurements. Look for a result labeled peptide content, net peptide content, assay, or quantitative peptide mass, and confirm which testing method was used.

If the report specifically identifies 11.4 mg as measured peptide content, the submitted vial tested above its labeled strength. A result of 8.7 mg would indicate that the submitted vial tested below its labeled strength.

When using a reconstitution calculator, a credible quantitative result from a batch-matched report may provide a more accurate basis than the labeled vial strength. Testing one vial still does not establish that every vial contains exactly the same amount.

HPLC purity and identity testing do not establish sterility or injectable safety. Separate tests answer separate questions. If a result is not listed, do not assume the test was performed.

• Sterility
• Bacterial endotoxins
• Bioburden
• Residual solvents
• Heavy metals
• Other specified contaminants

Review the date received, date tested, report date, and lot production date when available. A report from years ago—or one repeatedly used for newly sold batches—should not be treated as proof of current batch quality.

Whenever possible, verify the report directly through the laboratory’s website or by contacting the laboratory. Do not rely solely on a QR code that leads back to the vendor’s own website.

• Laboratory name and address
• Contact information
• Report or sample number
• Testing methodology
• Authorized signature or approval
• Independent verification link or QR code