I've taken L-Theanine with my coffee for years. The effect is subtle, but it's remarkable - I just look back over the last few hours and realize that I was distraction-proof.

I haven't dabbled in anything else because I don't really like the idea of messing with my brain chemistry too much. Theanine gets a pass because it's just an amino acid, is naturally present in green tea, and is considered extremely safe.

I'll happily recommend it to anyone looking to experiment without too much fear of side effects.