WOW... I'm glad I read this thread! I've been on the quest for a "Limitless" pill for years - even before the movie came out. I'd done reasonably well with my own "stack" of supplements, stuff like caffeine of course, ginseng, 5htp, ginko, even noopept at one point (which did little to nothing for me during my experiments) etc. etc. But I had never added theanine to the mix - until now!
To try something different, today rather than taking ANY of my standard regimen, I took only caffeine and theanine. I have some 150mg caffeine capsules I made up myself a while back during some other experiments, and my partner takes Theanine already so we had it in the house. I took 150mg of caffeine and 300 mg of theanine, and WoW0w... definitely can tell that I'm artificially stimulated, but it's not like straight caffeine would normally be. There is a smoothness to it that is not normally present, and it lacks the slightly-uncomfortable jitters I would normally observe. It also "snuck up on me" quite smoothly over about 20 minutes. Overall I'm moving faster, multitasking better, focusing better, keeping multiple threads going in my mind at the same time and not losing them like I sometimes do... Will be very interesting to see what happens in about 3 hours or so when I would typically notice a crash begin.
This is all around freaking awesome. I do believe this may get me a significant step closer towards my goal of a simplified regimen that gets me the cognitive/productivity results I'm looking for, at a relatively low cost and without a ton of ingredients or complexity.
Thanks so much to the OP for posting this thread, and I'm very glad I happened to spot it this morning. Theanine is definitely going into my routine for a while at least!