Well, it took about a month to kick in. I'm reading a bunch for my Masters and I found that I was more able to mentally connect things together.
I originally tried some for two months and came to the same conclusion, then went off it to see if it was the Neuro stuff or just my imagination.
IMHO, I did notice a difference when I was taking it, some I'm taking it again.
I think some folks were talking about better sleep effects and brighter visual colors, but I didn't notice that.