One batch, one report
A COA describes the material from a single production batch. A certificate for a different batch, or one with no batch number at all, tells you nothing about the vial in front of you.
What a peptide COA should contain
In-house or third-party?
An in-house COA is written by the seller's own lab. A third-party COA comes from an independent lab with no stake in the result. Many independent labs let you check a report on their website using a code printed on it.
Educational information only. Nothing here is medical advice, dosing guidance or a recommendation to use any substance. Research peptides are not approved medicines and are not for human or animal consumption. Speak to a qualified professional and follow the law where you are.