If the border official finds you are carrying prescription medication that is not for you and for which you do not have a prescription, it will be confiscated. If it is a narcotic medication you could be in big trouble. Metformin will not cause legal issues I would guess, but it is not OK to carry it in for someone else without a prescription. Of course, in most cases the border official will not find out and will not search you.
Metformin is not very expensive in Canada, so I would not risk it.
makes sense. thanks canadianwoman
