First off, there doesn't seem to be much benefit in taking more than what's already present in a cup or so of good green tea, though, so the exact content in va

First off, there doesn't seem to be much benefit in taking more than what's already present in a cup or so of good green tea, though, so the exact content in varieties probably doesn't matter. If you ever get bulk l-theanine powder (it's quite cheap), you'll recognize the taste. It's particularly prominent in sencha, gyokuro, and other Japanese green teas - that savory/salty/MSGish taste. Anecdotally, l-theanine negates most of the jitteriness from caffeine for me. Coffee, pop, etc. make me edgy in a way that tea doesn't.