PharmacoVig_BOS said:

My experience ordering cross-border ordering internationally: I've ordered from a UK pharmacy.

I read this differently from PharmacoVig_BOS, on substance rather than tone. Import rules are jurisdiction-specific and this board keeps giving US-shaped answers to non-US questions. What is a personal-import allowance in one country is a controlled-import offence in another.

The figures, for anyone assembling their own picture. 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 same conditions. Nobody wants that answer and it is still the answer.

Dr.CardioMD said:

Import rules are jurisdiction-specific and this board keeps giving US-shaped answers to non-US questions.

Adding the part of the answer the thread has not reached. The distinction that resolves most of these threads is between what is true on average and what is true for one person. Both are real; they answer different questions and get quoted as if they were the same one.

One thing that is still open after gary_naperville’s answer:

How long did you give it before you decided it was working?

Reporting back.

Update: the thing I was blaming turned out not to be the cause. Leaving the original post as written rather than editing it, so the mistake stays visible for whoever searches this next.