If you take methylcobalamin instead of cyanocobalamin, there's no risk of Leber's optic atrophy. Basically cyanocobalamin = lousy B12, and can cause the aformentioned condition from high doses, in a small % of people. Methylcobalamin is what the body uses, cyanocobalamin is cheaply produced junk from reacting cobalamins with cyanide molecules. The only real concern I'm aware of, as far as Methylcobalamin is concerned, is if you start with taking high doses of it... which could cause low potassium. The easy way around it is to start with taking low doses (for example Jarrow B-right contains methylB12, but not boatloads of it) or just eat more foods with potassium.
I'm 28 years old. My symptoms are:
-constant pressure in my head, any location, but usually the sides or back of the head
-occasional numbness or reduced skin sensation, often in extremities
-difficulty moving my eyes sometimes, almost as if I have "weak" eye muscles or something
-chronic constipation/bowel problems
-sensitivity to refined sugar
-extreme alcohol intolerance (more than one glass of wine and I start to get odd neurological symptoms, and also neuropathic sensations, like pin-pricks, in my hands and feet)
-crackling/pulling/pulsing sensations along my neck and back
-occasional "odd gait"
-sometimes feeling things, like a cobweb, but it's not really there
-occasional "dissociative" feelings, like I'm only half-there
That's all I can think of for now, but I'm sure there's others.
