I used to use a pinch of Acccent (pure MSG) to reboot my brain before important meetings where I really had to be sharp as a tack but was not feeling 100%*.
Used judiciously, it was a brain booster, otherwise it would give me a headache. Also unfortunately, MSG in any snacks or foods containing it (and a lot do, under disguised names) would keep me awake at night, with my brain running like a buzz saw.
I have no doubt that MSG or derivatives are in a lot of those brain boosters you can buy OTC.
Terry, 230RN
* Usually, but not always, due to the aspirin I take for arthritis. Aspirin can dull your thinking quite a bit.