in that whatever amount your body doesn't need/use simply goes thru your system.
The only one I recall and have and bad experience with is too much B6. That can build up and be detrimental. It had turned out the the multi-vite, b-complex and other supplements included waay too much B-6 So I switched brands and all is ok.

Don't be too distressed at the burning, it could be signals of healing. The majority of the B vitamins are key building blocks in helping that healing. - j