Since you're taking hydroxocobalamin with the cyanocobalamin you're probably ok, but I thought I'd mention it anyway. Maybe you could try a small amount of sublingual methylcobalamin and adenosylcobalamin to augment your hydroxocobalamin injections.
Xylitol is a sugar alcohol, not an artificial sweetener. I do agree that sugar alcohols aren't good to take. Some of my sublinguals have sugar alcohols and one of my protein powders also does, but other than that I mostly use stevia as a sweetener. Of course I'm not convinced that stevia is 100% ok to take. I'm not sure if there's much information saying that stevia is bad, but I'm not sure there's been studies on stevia either so we really don't know if it is safe. As for the xylitol I buy in bulk, I don't use that as a sweetener. I actually use that to make my own saline nasal spray:
http://forums.phoenixrising.me/inde...ay-for-sinus-congestion-sinusitis-save.21430/