Dr.LeslieOBGYN said:

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

International shipping tracking for cross-border ordering orders: my experience with customs in the US when ordering from overseas:

Seized and destroyed — had to get a reshipped package.

Tips: always include a copy of your prescription, declare medication properly on customs forms, keep quantities reasonable (personal use = 3 month supply max), and use a vendor who has experience shipping to your country.

Dr.SportsMedIN said:

Agreed, with a caveat about community reputation: it is a lagging indicator.

This is exactly what I could not find anywhere else.

Dr.LeslieOBGYN said:

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

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.

The figures, for anyone assembling their own picture. 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.

Moderator note: two posts asking for a source have been merged into one. Please search the thread before asking again. Carry on.