I have been taking 2x750mg of aniracetam (Pfizer) plus 1 spoon of soy lecithin daily for 1 year, after breakfast and after dinner.
In my anecdotal experience, the effects took >1-2 month to take place. After this time, I've noticed an improved memory, making it both faster and more accurate (in the sense that remembering was effortless and come naturally). This was very useful since I was taking a lot of demanding classes at university.
I also noticed a greater insight into the subjects presented. Learning was easier than when I was off aniracetam (year before).
What apparently didn't improve was the attention span (which is normal anyway) and ability to study for longer periods of time, this is to say, aniracetam is not a stimulant.
I should add, also anecdotally, that I got the highest grades in almost all the classes (9-10) that I took that year, compared to around half of those I took the year before.
This is of course a subjective perception and one should not conclude anything. It's possible that the effects were placebo and I was actually more prepared for the classes regardless of aniracetam, than the year before. On the other hand, it's very possible that the drug indeed enhances the cognitive performance.
Personally, I abandoned aniracetam because the effects don't seem to be clear enough to justify its price. It is, however, very interesting to be able to enhance the brain functioning in an apparent deeper sense than with stimulants, which have serious side effects, and I'm open to more experimentation in the future.
The text above was typed by frenzy monkeys randomly hitting their keyboards.