From SF Gate:
As druggists mix customized brews, FDA raises alarm
Today, the Food and Drug Administration says "virtually all" compounded products are technically illegal. But since it recognizes that much of what the compounders offer serves a legitimate need, the agency is selective in its enforcement. The FDA generally targets only large-scale compounders who are acting more like manufacturers than corner pharmacies.

(Editor's Note: Although not specifically related to Canadian pharmacy, this article discussing regulation of compounding pharmacies is relevent to pharmacy in general.)