GFN,

I had the twitching and ballistic movements (the arm just takes off in a ballistic trajectory when all I tried was a small movement). I found that I needed to protect my neck. Minor inflammation would interrupt the nerve functions and strange things would happen. ice your upper neck and relax in a straight posture. No tilting the head forward or to the side.

The inflammation usually take 10 to 20 minutes to start to interrupt nerve signals. I take gabapentin (prescription) before bed to help these problematic nerves from disrupting my attempts to sleep.

Yes, you can take the higher dose of B-12. A 1000 or 2000 mcg dose per day should be OK. Some people do not absorb B-12 well. They need a methylated version of B-12. Methylcobalamin is the preferred version. Check you B Complex to see what kind of B-12 is included.

If you are concerned about the supplements causing your twitching, list the ingredients and dosages. Maybe there is something odd in your supplements. Do you drink coffee or caffeinated beverages ?