B-6 one can get toxic effects from...just web up 'B-6-Toxicity'.
B-12 it's really really hard to get toxic effects from. Web it up...should be hard to find. That there are different forms of B-12, as all say, is what you can get is part of the issue. Most B-12 overdoses are like trying to OD on Vitamin C...it just passes thru you.
But, making sure what all B-12 that's swimming around in your blood and actually being asorbed and used...well that is a different issue. Blood tests really don't tell docs what's BEING USED, just what's out there in your blood to BE used. Big difference. Only way to be sure are thru biopsies and since we are 'susceptable' to begin with...this isn't a way to go. Not worth it, and the tests to date are filled with room for error.
SOO, If asorbtion is an issue [as is possibly my own case] taking the Methyl...and well, doing what atheletes do to hydrate before running races [overload or 'pack' the stuff] increases your chances of 'taking up' what you need. Since taking too much usually is very hard to hurt you, it should be worth trying for, say about 3-6 months? and see if anything [maybe slowly] makes a difference?
B-6 on the other hand can cause problems....I know it's confusing, I've been working on it for the 3 years I've been on this and other boards and I'm still confused.
It's the get too much info and the brain circuits fry - syndrome! Don't know how else to put it.
YOu are on the right track, learning asking questions - but it's YOU who has to decide what is good for YOU! No one else can do that! 's - j