A batch that came back wrong and what the member did next

Something practical: I photograph the vial, the label and the paperwork on arrival, every time, before anything else happens.

What I have learned here is to be much more sceptical of a claim with no document behind it than of a document I find hard to read.

I would say ask for the batch record and see what comes back. The suppliers with a real documentation process send it without a fuss.

I found the questions list on the reference pages more useful than any of the prose, because it gave me something to actually do.

Something worth knowing: certificates carry different things. The ones worth having name the method and the column, not just a percentage.

My honest position is that I would rather this community discussed this openly than left the question to be answered by somebody selling.

The independent testing services people use here are Janoshik, Medutest, PeptideMeter and VendorInvestigate, and commissioning your own is the only result you commissioned.

I would gently say that no amount of documentation makes this equivalent to a prescription, and anybody telling you otherwise is not being straight with you.

I asked for the certificate for my specific lot rather than a representative one, and the answer to that request tells you a great deal.

The check I would not skip is the lot number on the vial against the lot number on the document. It takes ten seconds and it is the only check that is entirely yours.

What our sourcing reference pages do is say what can and cannot be verified about a supplier. That is a narrower thing than a recommendation and it is deliberately narrow.

My approach is to ask three questions before ordering anywhere, take the answers as data, and treat a non-answer as an answer.

Something I would flag about the wider market: a great many names have a handful of submissions, no consistent documentation and nothing verifiable at all behind them.

What I found is that a supplier with hundreds of independent results behind it is a genuinely different proposition from one with four, and the difference is not marketing.