One concrete data point for the thread. 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.
A narrower follow-up, since the general answer is now clear:
How people are distinguishing a supplier having a bad batch from a supplier on the way out?
jason_paloalto said:Red flags, in rough order of how much they should worry you: no verifiable address, no batch numbers, prices far under market, vendor-commissioned…
Adding the part of the answer the thread has not reached. 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.
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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.
Dr.LeslieOBGYN said:Prices dramatically below market are the strongest single signal, and the reason is arithmetic rather than suspicion.
Agreed, with a caveat about community reputation: it is a lagging indicator. Reports arrive weeks after orders, so a supplier can look excellent for a month after quality has already changed.
Happy to go further on any of that.