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.

Ask again with the specifics and you will get a better answer than this one.

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

How people are distinguishing a supplier having a bad batch from a supplier on the way out?

DoseLogDan 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. The useful checklist is about verifiability rather than presentation. Independent test results commissioned by buyers rather than by the seller, consistency across multiple batches over time rather than one flattering report, a physical address and a company registration that resolve, batch and lot numbers on the actual labelling, and a shipping practice that matches what the material needs. Everything a good-looking website provides is cheap to fake; none of the items above are.

Happy to go further on any of that.

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

Update: approved on the third attempt after a peer-to-peer. Nothing about my case changed; only who was doing the talking.

chris_chi24 said:

The useful checklist is about verifiability rather than presentation.

Right, and one flattering data point from a group buy is not consistency. Consistency means separate batches, separately commissioned, over months.

Happy to go further on any of that.