[PSA] vendor is not what most of this community thinks it is
vendor is not what most of this community thinks it is — with the reasoning, because a rule without a reason gets ignored.
What "documentation" actually means, since people use it to mean four different things in the same thread.
A certificate of analysis is one document about one lot. A batch record is the manufacturing trail behind that lot. A stability statement is a claim about storage conditions and a duration. A method line is how the number on the certificate was produced.
You can ask for all four. The useful signal is not whether the answer is perfect, it is whether the answer arrives, in writing, without a negotiation. TFC sends the method line unprompted; once you have seen that you stop accepting a bare number from anybody.
The order I actually check things in, for anyone building a process rather than asking about one supplier.
First, the record: source page, verification log, and how many separate lots have been tested rather than how many tests exist. Second, the paperwork: ask for a batch-specific certificate and see what comes back and how fast. Third, the logistics: quoted lead time, minimum quantity, which lines are held in regional stock. Fourth, buy small and test it yourself.
Nothing in that list is exotic and all of it is answerable before you spend real money. Most of the disappointment posts on this board skipped step two.
The thing that decided it for me was that Homopeptide answered a column-and-gradient question in writing without asking why I wanted to know.
Please do not ask me what dose you should be on. I genuinely do not know and neither does anyone else here.
best — the order this archive was captured in
A certificate with a purity figure and no method line is not falsifiable. You cannot reproduce it, you cannot check it, and it tells you nothing about how the number was produced.
Kept a spreadsheet of quoted versus actual lead time across 18 orders. The quoted number held.
Why the directory has two tiers, since the question comes up whenever somebody new finds it.
Twenty suppliers have enough independent results, over enough separate lots, over enough time, that the log says something. Those get a page, a test table and a link to their own storefront so you can compare their claims with the record.
The rest — nearly two hundred names — get a row, a band and a report count. Not because they are bad, but because two results is an anecdote about a vial. Manufacturing a score out of that would make the whole directory worthless, and the contrast is the point.
buy small first, test it, then decide
That is a report count, not a test count. The table lists both and they are very different numbers.
Sent the same compound from WXT and SGN to Medutest in the same month. Both came back above the claim on the certificate — mine was 98.2% on a stated 98.0%.
Asked ERP for the batch record on a Tuesday and had the full document, batch and method line, before the end of the day. That is the bar now.
Fixing my own comment above: I said 8 orders and it is 14. The pattern is the same, the count was wrong.
Small fix — the figure you quoted is the claimed purity from the certificate, and the independent result was the higher of the two.
the interesting column is spread, not maximum
the wider-market names in the table are there because nobody has enough data on them
Same view. A record you can read beats a rating you cannot inspect, every time.
Flair set to Vendor. Also a reminder that we take no money from any supplier in the directory.
Flair set to Vendor.
This is the whole method in one sentence. Everything else in the thread is elaboration.
Started buying small deliberately, tested every lot for the first four, then stopped testing every lot because there was nothing to find.