I use aniracetam (500mg twice daily) together with a choline supplement. It definitely improves my cognitive stamina: while I don't think it boosts my 'peak' ability, it increases the amount of time I can operate at that level.
It doesn't seem to be right/left-brain specific, either - my wife (a psychotherapist) finds it similarly helpful.
Regarding side effects, I had some headaches and disorientation during the first week, but nothing after that.
I think he meant something in the line of sources of clinical trials etc. Nonetheless, the sources on Wikipedia suggest that they have been extensively tested in mice, like all the other stuff we take. And they do have proven use in treating Alzheimers etc. They are considered nontoxic or even neuro-protective, but in my opinion often sought out for based on reviews from first users who are mostly biased from the start and therefor easily placeboo'd. No offence :) I'd love to try them, but I'm in dubio for reasons stated above.
I first read about nootropic drugs 15 or so years ago when I picked up a small book on the topic. Pricetam seemed like an effective drug with few side effects, and it could be bought over-the-counter in Mexico. I was living in San Diego, so I picked some up at a pharmacy and gave them a try. I did notice a significant impact on my concentration and mental clarity when taking the dosage recommended in the book. I think I finished off the bottle of a few months but never really thought about trying to get more. I think it was mostly because of not really knowing the side effects and not wanting to alter by body's natural chemistry too significantly.
It doesn't seem to be right/left-brain specific, either - my wife (a psychotherapist) finds it similarly helpful.
Regarding side effects, I had some headaches and disorientation during the first week, but nothing after that.
Better living through chemistry :-)