SleepDoc_PDX said:

The pattern that distinguishes a bad batch from an exit is behaviour rather than product.

This is exactly what I could not find anywhere else.

Clinical perspective, offered as context rather than as advice. Order of operations matters more than any single choice here: establish a baseline, change one thing, wait long enough for it to express itself, then measure again under the same conditions.

Correct me if the detail matters more than I have assumed.

jim_asheville said:

Vendor reputation tracking for vendor vetting: I maintain a personal spreadsheet with every order I've placed — date, vendor, batch number, Janoshik…

Filing a mild objection. Mild because I might be wrong; an objection because nobody has addressed the case that does not fit. The objection nobody has made: this only works if the measurement is doing what we assume it is doing, and that assumption has not been tested here.

One concrete data point for the thread. Give anything pharmacological four weeks before you judge it, and give anything measured weekly a four-point rolling average before you call it a trend.

Happy to go further on any of that.

Moderator note: two posts asking for a source have been merged into one. Please search the thread before asking again. Tagging this one for the weekly digest.