Can someone fill me in on if this information is accurate or not. I was talking to the guy who runs the B12Oils website, he is quite knowledgeable about B12 issues, but when I asked him about B12 healing symptoms ("Start Up"). " Is it true that it's normal for B12 to cause certain negative side effects if you have been deficient for so long, as the B12 is making the body do things it hasn't done in a very long time? It sounds like a way misunderstood rumbling from the web. If you have a vitamin B2 deficiency, then you may react to folate and/or methyl B12. " So basically he is saying B2 deficiency is the cause behind the symptoms some get when introducing B12 into the body. Obviously B vitamins are very important, but is there any information that suggest this is remotely the case? I had potassium deficiency symptoms that went away when I supplemented with potassium gluconate, so I am thinking he may be wrong in this area.