A supplier that answers analytical questions with restated claims

On the subject in the title: A supplier that answers analytical questions with restated claims Working notes rather than a conclusion.

Reading back through what has been written here about supplier, three questions come up every time and only one has ever been answered properly.

Listing all three, with what I think the state of the answer is for each, so the thread can start further along than the last one did.

Building on post #2 rather than restating it.

Being wrong in public about a supplier is costly to that supplier and to the person who was wrong. That is why the evidence standard is what it is.

Confirming post #11 from a second method, which matters more than confirming it from a second person.

The strongest single signal available cheaply is what happens when you ask a technical question. A quantitative answer inside a working day is difficult to fake at scale.

That reframing is the whole thing. The facts I already had.

Exaggerated claims without documentation: every compound has limits. No peptide is "100% pure" because purity is measured to finite precision. A supplier claiming implausible perfection without backing evidence is overreaching.

A qualification I should have led with rather than closed on.

I had read the opposite somewhere and cannot now find where, which tells me something.

Claims of pharmaceutical-grade status for research-use-only material are a labelling problem and are common enough to be worth expecting rather than reacting to.

That holds under the stated conditions and I have stated them.

Practical answer on supplier, since the theoretical one is upthread: do the simplest check first, write down the result, and only then decide whether the complicated explanation is needed. It usually is not.