Dr.CardioMD said:The useful checklist is about verifiability rather than presentation.
I disagree that testing history is decisive. It tells you what a supplier did when they were being watched. Continuity of behaviour under stress — a late shipment, a failed test, a complaint — is more predictive than any run of good results.
Happy to go further on any of that.
SaraMom3 said:Eight months with one supplier, then a change in how they communicate that I noticed before I noticed anything about the product.
Shipping damage protocol for vendor vetting orders: if your package arrives with visible damage, temperature excursion, or broken vials:
Reputable vendors will replace damaged shipments without argument. If they push back, that's a red flag about the vendor.
RetaRick_CA said:I disagree that testing history is decisive.
Adding the part of the answer the thread has not reached. Worth answering the question that was asked rather than the one behind it. The narrow version usually has an answer; the broad version usually does not, and answering the broad one is how a thread stops being useful.
Certified reference materials, analytical reagents, and research-grade standards for peptide verification. Trusted by laboratories worldwide.
Shop Reference StandardsOne thing that is still open after LibrarianMeg’s answer:
How people are distinguishing a supplier having a bad batch from a supplier on the way out?
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.