[pnm45678]

> I think these are the possibilities:

> Theanine works, but I got fake theanine. <…>

I’d add one more possibility: “Theanine works but I need a higher dosage to feel the effect.”

FWIW my purely anecdotal findings are that supplier does matter. Natural Factors Suntheanine gave me a noticeable effect. Nature’s way L-Theanine did not.

[A7C3D5]

I used to take theanine in college, and this was my experience even over a decade ago.

Suntheanine was consistently effective and most of the other brands were seemingly inactive or unnoticable. I've always had to order online as all of the brands I've bought in store seem to be bunk.

Even still I found tolerance to rise quickly with daily theanine use.

[MichaelDickens]

OP took 200 mg. Tea contains 5–20 mg and people commonly report beneficial effects from tea. If 5 mg is enough for some people then surely 200 mg would be enough for anyone?

[Arch485]

Not necessarily, there are a lot of drugs that have reduced or no effect for certain individuals. Think caffeine or alcohol tolerance.

[slama]

I thought I was crazy/imagining things, but I had a similar experience. Maybe I should try Suntheanine again