It's very individual where you should draw the line with B-vitamins. I for one have very fast metabolism and im sensitive to chemicals so for me 400mg was way too much already. I had my worst nightmares ever and woke up feeling like someone had drilled holes in my brains during the night, so i hit the neurotoxic limit with that low dosage already. But on the other hand, i cannot even drink coffee or some other liquids with high caffeine value as they make me feel ill. Once even went unconscious from drinking about liter of coffee. So nowdays its green tea only for me, and B6 50mg caps at max and not everyday.

But yeah, great stuff for dream recall, and changing your urine colour for green.