I have been using Beta Alanine for 4 weeks now, and I already feel quite a large benefit. The thing I find with supplements tho is that you never know if it the supplement or something else that is causing the improvements.
I have heard that only certain people respond to Beta Alanine. Apparently, if it makes your face itch, its not working on you. It does make my face itch alot, but it has got better recently, so perhaps my body has got used to taking it up?