GGPeps domestic shipping is FAST — what worked for you?

Adding the clinical framing, because it changes how the question reads. There is a difference between no evidence and evidence of no effect, and this subject is one where the two get swapped freely in both directions.

Dr.AddMedPHL said:

The boring version of this is the one that works, and the boring version is: measure a baseline, change one variable, wait, measure again under the…

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.

Worth separating that from vendor vetting, which this thread keeps folding into the same question. They behave differently and the advice does not transfer.

One concrete data point for the thread. If you are comparing against somebody else’s result, check that you are comparing the same measurement taken the same way. Most of the apparent contradictions in these threads dissolve at that step.

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?

Moderator note: good thread. Keeping it here rather than moving it, because the question is general enough to be useful.