I generally have insomnia or a wired reaction from most any supplement that lists it as even a mild possibility. This is even in small doses taken early in the morning. I want to add B vitamins to my regimen since I'm taking B6 and I think I read that if you take a B vitamin you need to take all of them or else the levels of the others will get low. I'm trying to decide if I should buy a B complex or try to buy each B vitamin separately. I normally do not take combined supplements because I react to so many that I like to only add one new thing at a time. Do the B vitamins all have similar effects as each other or does it make sense for me to add one at a time to check for side effects like insomnia and other things (if that's even possible I don't know if stores sell them separately)? I also like to tailor my doses since I usually take less than one serving and that would be easier to do for each vitamin if I took each separately.