There are several Canadian online stores; I think it's legal there.
I used California Vet Supply, it was cheaper, faster, and the same manufacture as the human grade... although I still get the willies seeing the doggie on the vial.
It is water based;
preferable injections are IM, although SQ is fine. (SQ absorption is slower)
I do 2,000mcg once a week. You can't really OD on B12, if you take too much your body flushes it, and I've read anything over 2000-2500mcg is pissed away.
If you are B12 deficient you will notice the energy increase if not then you’re going to think it’s a waste of money. That’s why you hear some people swear by it and other say bunk. It’s not tweaky energy like caffeine or amphetamines; I call it “real” energy because you really don’t notice that it’s there until it’s about 1AM you’re just not sleepy.
The reason I started taking B12 shots is that I take stomach medication, if you take any thing like Pepcide, Tagament, or any of those then you are B12 deficient. And if you are taking orals , gels, you are getting 10% of the dose. Oral is a waste because of saliva and stomach acid. Nasal gel is better, IM is best.
Finally, if you’re buying BA water for HCG, you can use B12 instead, both are water based.