Kieran, you can't assume that L-Glutamic Acid, L-Glutamine or Glucosamine or whatever, will actually help YOU with your brain-fog - because brain-fog have many, many different causes.
You need to figure out first, why you, specifically, have brain-fog. Test yourself and talk to Dr's about this problem and see what they come up with - do some blood-work, see if you have any deficiencies detectable in blood.
I had a look at your other thread again, and especially your reaction to Kratom.
http://www.longecity...ndpost&p=808055
I haven't had a look at this plant in the past, but it seems to have an IMMENSELY complex mechanism of action! One thing I note though, is that it has some effects on dopamine and NOREPINEPHRINE, which seems to be the strongest upon first use of the plant.
And as I recall, you had never tried any Norepinephrinergic antidepressants? Bupropion (wellbutrin, voxra) and Duloxetine (cymbalta) come to mind off the top of my head.
You need to have a look at those drugs, and seriously consider them - there IS proof that they help with cognitive deficits in several different psychiatric disorders.
NE is a helluva' drug, man.