For those of you taking L-Theanine make sure that you are buying the SuntheanineŽ brand of it. All of the other forms of this amino acid use a different manufacturing process which does not provide the same effect and could be toxic. Suntheanine is produced my a natural method and all others are produced by chemicals. The ones produced by chemicals product 2 forms of theanine and the other form is R-Theanine which can be toxic. Hope this helps!