That is weird. Magnesium is actually a muscle relaxant and so should make you a little sleepy if anything. I take 500 mg/day for migraines as a supplement (no idea how much through food) and have never noticed any difference in mood. I don't know anything about the oil.

But we all know that bipolar responds weirdly to so many things. So it's certainly not impossible. The same neurologist who put me on magnesium wanted me to take CoQ10 and that made me hypomanic. My sister (who isn't bipolar) had agitation from it and warned me to be careful and sure enough 2 pills in I was agitated and it stopped when I stopped the CoQ10. So anything is possible.