Well I can contribute something to theanine side effects too.
so how much tyrosine were you taking? daily? i guess those would be a factor, now that i recall i've taken both in a supp. (unknown amounts), had no issues.
Again my problem was elevated GABA from something else i took, theanine was quite a few days before this.
It certainly was not the GABA - gaba gamma amino-butyric acid cannot cross the blood brain barrier -- GABA supplements are worthless.
The reason Phenibut was synthesized is because by adding a phenyl ring to GABA as in Beta -phenyl - gamma -amino butyric acid (Phenibut), it crosses the blood brain barrier.