Not veterinary advice. If your dog or cat has a health concern, talk to a licensed veterinarian. Nothing on this site is approved for use in pets.
Sellers of research peptides love to say "COA available." A certificate of analysis can be genuinely useful to a laboratory, but only if it's tied to the exact lot in hand and names how and where the testing was done. This guide covers the fields that matter, the red flags, and the one thing a COA can never prove.
Key takeaways
- 1.A COA only describes the lot it was run on, so its lot number has to match the vial.
- 2.Purity usually comes from HPLC, and identity from mass spectrometry. A solid COA reports both.
- 3.No lab name, no method, no date, or a lot number that never changes are all red flags.
- 4.A COA describes what's in a vial. It says nothing about whether that material is safe or approved for any animal.
What a certificate of analysis is
A certificate of analysis is a lab report for one production lot. It usually lists the compound, a lot or batch number, the test date, the methods used, the results, and the laboratory that ran the tests.
Because it describes one lot, a COA is only meaningful for vials from that lot. A certificate for a different lot, or one with no lot number at all, tells you nothing about the vial in front of you.
The fields to check, in order
Read a COA from the top down and check each of these:
- Lot or batch number: it must match the number on the vial.
- Laboratory: the name of the lab that ran the analysis. Independent labs are easier to trust than in-house results.
- Test date: a real date, reasonably recent for the lot.
- Methods: named methods such as HPLC and mass spectrometry, not just "tested."
- Results: a purity figure and an identity result, with the instrument traces attached.
HPLC and mass spectrometry, in plain English
HPLC (high-performance liquid chromatography) separates a sample into its parts. The result is a chart of peaks, and the purity figure is roughly the share of the total that sits under the main peak. One tall peak with little else means a cleaner sample.
Mass spectrometry weighs the molecules. If the main signal lands at the expected molecular weight for the peptide, that supports its identity. Purity without identity tells you a sample is clean but not what it is, which is why the two are reported together.
Red flags
Be skeptical of a certificate when you see any of these:
- No lot number, or a lot number that doesn't match the vial.
- The same certificate image used for every lot or every product.
- No laboratory name, no methods, or no date.
- A purity number with no chromatogram or spectrum behind it.
A purity percentage on its own is a claim. The lot number, lab, method, and traces are what make it evidence.
What a COA can never tell you
Even a perfect COA only describes chemistry. It doesn't make a compound safe, effective, or legal for use in a dog, a cat, or a person, and it doesn't stand in for FDA approval.
That's why Peptides for Pups shows the documentation status of each listing and treats a source catalog's purity figure as unverified until the original record can be matched to a specific lot. You can see the current status on our evidence page.
Frequently asked questions
The lot or batch number. A certificate only describes the lot it was run on, so its lot number must match the one on the vial.
It usually means at least 99% of what HPLC detected was the target compound. It doesn't confirm identity on its own, which is why mass spectrometry results matter too.
No. A COA describes what's in a vial. It says nothing about safety or effectiveness in any animal, and it is not FDA approval. Talk to your veterinarian about your pet's health.
Sources
Research use only
This article is general education, not veterinary advice. The compounds listed on this site are laboratory reference materials. They are not FDA-approved for use in dogs, cats, humans, or any animal, and must never be given to a pet. If your dog or cat has a health concern, talk to a licensed veterinarian.
