I have been low in B12 and folate, it seems for a while now. I suspect also that I am also low in B6 and zinc as well (Pyroluria), but I don't seem to have a problem tolerating those. Every time I have tried to take B12 by itself (meaning not mixed in something else like a multivitamin), I can't tolerate it. It gives me palpitations and makes me jittery. I just tested low for it again and desperately want to get on some, but not sure what to try. Shots are not an option. Thanks.