Boy do I hear you on the supps! I can't even really tolerate them, so I avoid them, but b12 is unique and in a class of it's own, IMHO. Also, I am vegan, so I am def not getting it in my diet.
I am using this outline of Freddd's protocol. I am titrating up with the active b12's and folate as I have CFS and can't afford any crashes or "healing" crisis anytime soon.
I am taking 1/3 tablet of mb12 every morning after breakfast, must keep it under the tongue as long as possible. I did that for 3 days, then added in 1/4 tablet of 800mcg folate. That made me feel good, amazingly. I did have some of what Freddd refers to as "start up" reactions to the tiny amount of mb12, like dizzy, drunk feelings. This means I really need the stuff so I am happy I'm on to this.
Then after 7 days, this wed., I will add in the adb12, which is the other active form of b12. This outline really helps to understand the process better.
Also, the way the body uses b12 is still over my head, but I found this thread on Andreas' forum. He didn't seem to think the liver flush washed it all out, but some practicioners apparently do believe that, so maybe nobody knows. Regardless, a lot of ills are associated and being reversed with this protocol, so I think it's something we should all investigate, try and then adopt or rule out before we do more invasive things, IMHO.
I also am finding quite a bit of good info on this site regarding nutrigenomics and b12, etc: