dan_philly said:Say what you would expect to see if you were wrong, before you look.
Saving this. It is the first explanation that did not require me to already understand it. Taking it to my next appointment.
Clinical perspective, offered as context rather than as advice. The version of this that has an answer is narrower than the version being asked. Narrow it and it becomes tractable; leave it broad and the thread will produce nine confident and incompatible replies.
LibrarianMeg said:The version of this that has an answer is narrower than the version being asked.
Second this.
Certified reference materials, analytical reagents, and research-grade standards for peptide verification. Trusted by laboratories worldwide.
Shop Reference StandardsLibrarianMeg said:The version of this that has an answer is narrower than the version being asked.
There is a second half to this that has not been said yet. 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.
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.