The first time I tried Ltheanine, I took 400mg and was very calm, but I was also too hyped up to sleep. The next day, I took it at work and was feeling good for about 6 hours then took another 400mg dose around 6pm and then took passion flower extract to sleep around 11pm. The third day, I started having tolerance. Shook most of the day at work and finally feel calm this evening. I don't know if I am overdoing it, but 100 or 200mg did nothing at that dosage. I think for me, Ltheanine is a "once in a while" supplement. I may still play around with the dosages. I've even gotten tolerant to the passion flower. The first 2 days, I took it by itself and wanted to sleep all day. Now, a week later, I take it and have the opposite effect. The ltheanine does not have any interactions, but the passion flower may be interacting with the LTheanine. I have to stop putting the two together, I guess. I am still researching.
My worst time of day is the morning, driving to work. I get so nervous, I want to turn the car around and come home.