That has valerian in it. It's supposed to put you right out, but sedatives never had much of an effect on me. That's just my personal experience, I'm sure it works for other people.
I know just what you mean. Hell, even stimulants don't really have any affect for me (such as coffee).
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What part of Ph'nglui mglw'nafh Cthulhu R'lyeh wgah'nagl fhtagn don't you understand?