And it has not affected me. I've been taking it about a year. It's actually supposed to help with MS.
One thing I'll recommend though - the B vitamin works MUCH better when it's taken together with other B vitamins, you really should never JUST take B-6. I take a vitamin called B-Complex. There is also one called B-Stress that is awesome. They have B-6, B-12, etc. They work together.