Cold-chain shipping — which vendors use proper temperature control?

LabKate said:

The useful checklist is about verifiability rather than presentation.

Filing a mild objection. Mild because I might be wrong; an objection because nobody has addressed the case that does not fit. Import rules are jurisdiction-specific and this board keeps giving US-shaped answers to non-US questions. What is a personal-import allowance in one country is a controlled-import offence in another.

Correct me if the detail matters more than I have assumed.

The figures, for anyone assembling their own picture. Red flags, in rough order of how much they should worry you: no verifiable address, no batch numbers, prices far under market, vendor-commissioned tests only, pressure toward irreversible payment, and shipping with no temperature control.

DataDave said:

Import rules are jurisdiction-specific and this board keeps giving US-shaped answers to non-US questions.

There is a second half to this that has not been said yet. Prices dramatically below market are the strongest single signal, and the reason is arithmetic rather than suspicion. Synthesis, testing, and cold-chain shipping have floors. A price well under the floor means something was skipped, and the two things that get skipped are testing and content.

One thing that is still open after BiostatsBrad’s answer:

What a vetting checklist should actually contain, as opposed to a list of things that are easy to fake?

OP back with an update, since a thread like this is useless without one.

Went back through my own correspondence with an earlier supplier and the warning signs were all there in the replies, weeks before the quality changed. I was reading the product and not the behaviour.