A COA belongs to a sample, not to a supplier
A certificate of analysis records what a lab found in exactly the material sent to it. It names the substance examined, the purity result and the date. It says nothing about what is in another batch from the same supplier, and even less about batches made later.
A single report is therefore never a statement about a supplier, only about a sample. Only many samples, from different sources and from recent months, add up to a picture that holds.
The test is often not ordered by the supplier
A large share of the reports circulating in the market were commissioned by buyers. Someone orders peptides, sends a sample to a lab, pays for the test themselves and then posts the result in a group. Alongside that, organised testing groups pool money for a test and send in the sample together.
In those cases the lab only knows who commissioned the work. The report therefore carries the name of the buyer or the group, sometimes no name at all. The supplier the material came from does not appear on it, even though the report is very much about their goods.
Why such reports do not count
If a report does not identify the supplier itself, the link between sample and supplier is a claim made by whoever passes the report on. It may well be true, but it cannot be evidenced from the document. A supplier can also simply adopt someone else's report, and that does happen.
Only samples where the lab itself names the supplier are counted. The rest is not discarded: they appear on the supplier page as a number alongside, but they colour no dimension and lift no assessment. How that count comes about as a whole is set out in the methodology. The price of that strictness is that a supplier with many good yet unconfirmed reports looks paler here than they may be.
What even a clean report does not say
High purity says the substance examined was largely pure. It does not say how much active ingredient was in the vial, whether the amount matched the label, whether filling was sterile, or how the material was stored and shipped. Some of those questions have their own tests, which are commissioned far less often.
How contact with a supplier comes about in the first place is described on the page Buying direct from a supplier. A report also ages. Manufacturers change suppliers, staff and procedures. A result from two years ago describes a state from two years ago, which is why the age of the reports is shown alongside their number.
Even the reports that are counted here each attest only to the one sample examined. They are not a seal, not a guarantee and not a recommendation.