Short answer: do not rely on the PDF alone. Confirm that the laboratory is real, check the report number or code directly with the laboratory, and make sure the lot number on the report matches your vial.
1. Confirm the laboratory
Search for the lab independently, not through a link in the COA. Check that it has a real website, contact details and a stated scope of services. If it claims accreditation (for example ISO/IEC 17025), check that the accreditation covers the test methods used.
2. Use the lab’s verification system
Many labs print a verification code, access code, search code or QR code on each report. Enter it on the lab’s own website and compare every value with the PDF you were given. If no portal exists, email the lab with the report number.
3. Match the lot number
The lot on the COA should match the lot printed on your vial. If the report says “see flag tag” or shows the lot only in a photo, compare that photo with your label.
4. Check the client name
The client is the company that submitted the sample. If it is not the seller, ask the seller how the tested sample relates to the product they ship.
5. Look for signs of editing
- Fonts, alignment or spacing that change around results or names.
- Missing chromatograms or mass spectra.
- Dates or report numbers that do not match the lab’s format.
- The same COA used for many different lots.
6. Consider independent testing
For important work, some researchers send their own retained sample to an independent lab. This is the strongest check of all.
Each Guardian Labs testing record lists the lab, report number and any verification code printed on the COA. See the Certificates of Analysis page.
Related guides
- What Should a Peptide COA Contain?
- How to Read a Peptide COA
- Identity Testing vs. Purity Testing
- Why Batch-Specific Testing Matters
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All Guardian Labs products are sold for laboratory research use only. They are not for human or veterinary use, and nothing on this page is medical advice.