MikeFit_NJ 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.
tammy_FL said:Eight months with one supplier, then a change in how they communicate that I noticed before I noticed anything about the product.
Vendor reputation tracking for vendor vetting: I maintain a personal spreadsheet with every order I've placed — date, vendor, batch number, Janoshik result, personal efficacy assessment (1-5 scale), and any issues.
After 20 orders across 5 vendors: average purity 97.0%, zero sterility concerns, 0 shipping issues (all resolved). This data gives me confidence in my current source and documentation if issues arise.
I encourage everyone to track their orders systematically. Community data aggregation makes us all safer.
DataDave said:I disagree that testing history is decisive.
Adding the part of the answer the thread has not reached. The useful move here is to separate what is established from what is widely repeated. Those two sets overlap less than the confident tone of most write-ups suggests, and the second set is where nearly all the disagreement on this board comes from.
Sigma-Aldrich — Research-Grade Standards
Certified reference materials, analytical reagents, and research-grade standards for peptide verification. Trusted by laboratories worldwide.
Shop Reference StandardsFollowing on from DadBodDave — and this may be the naive question:
How people are distinguishing a supplier having a bad batch from a supplier on the way out?
Closing the loop on my own question.
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.