I just copied this from another thread and I thought I should share it with everyone:
The ONLY bad thing about taking BCAA's multiple times per day is that many manufacturers put vitamin B6 in their BCAA powders. Because B6 is used to metabolize protein, however, they put in TOO MUCH!
And the problem is that if you are taking in more than 200mg of B6 per day for a long period of time, it can cause irreversible nerve damage! So you NEED to count how much B6 you are getting in your foods, multivitamin, and BCAA's supplements.
Vitamin B6 - Wikipedia, the free encyclopedia
Just scroll down to the "toxicity" paragraph.
I just read the wiki and apparently its a little higher upper limit than I thought - so i feel like most people will be ok.
but its still something to look out for if you take a B-vitamin supplement in addition to your multivitamin.