And I'll say it again, but in my own topic: hair is ectoderm and the brain and spinal chord right down to the peripheral nervous system are neuroectoderm, or neural ectoderm to some, the result of the ectoderm turning inwards in the early stages of foetal development. I was taking 5000mcg of oral methylcyanocobalimin until about three months ago, now I take triple that at least and my hair has started growing exponentially, so I hope something is happening to my brain cells as well. Although it was my idea, David thinks it very sound, so told me to keep on with it. This link from the University of North Carolina is fascinating.....Sarah http://tinyurl.com/yy53n3 Edit, the day after the night before: should have written "Spinal cord" and "Methylcobalimin." Go to the back of the class. An Itinerary in Light and Shadow.Wheldon regime since August 2003, for very aggressive SPMS. Intermittent therapy after one year. 2006 still take this, now two weeks every three months. EDSS was about 7, now 2. United Kingdom.