Just a wee note re Dr PJ Nebergall's article:
I am Type 1 and take Metformin 500mg x three daily + Novorapid and Protophane. The good doctor states "metformin becomes useless..."
In my experience, it enhances the sensitivity to insulin, whether it is injected or 'home made'. I have decreased my insulin requirements by as much as 12 units per day, and I put this down, for the most part, to metformin's assistance (plus eating less carbs). It is a long time since I produced any insulin of my own !!
Eve