In the past, I've found that something in Jarrow's B-Right and (way back before I learned anything about methylation) chain drugstore B-50 complexes caused me to become really agitated, without much gain in energy level. Thorne's B Complex #12 was the first one that didn't cause that sort of reaction, but it having folinic acid turned me off after I learned more about it. I'm currently using Douglas' B Complex with Intrinsic factor, and it seems (fingers crossed) to be working well: So in my attempt to always do better, what generally causes poor reactions to a B complex, for most people? I know @Freddd is big on low dose B complexes, like the Nature Made. This has actually got me considering splitting the Douglas capsules in half to further reduce the dosage, while reaping the benefits of activated ingredients. Thanks for your thoughts, and hope this helps someone someday!