@Vegas
The Mg threonate helps with what I perceive to be glutaminergic overstimulation. It is quite calming to the brain, but doesn't provide enough Mg for the rest of the body, so I also use Mg citrate and Mg glycinate (at night, it's wonderful for sleep). I take 100mg elemental Mg in threonate form, I tried 150mg (the recommended dose) but this actually feels like it slows my thinking too much.
WRT GABA (for your daughter), you might want to look into PharmaGABA. I find this much more effective and much more smooth than the regular amino acid. Just 100mg is enough. Regular GABA gives me breathing problems, throbbing and tingling, but PharmaGABA just has a mild relaxing effect. I use this one, it also comes in a chewable version.
Many thanks for the tip on the 4-aminobutyric acid. I don't have these issues, so I couldn't effectively test them on myself. Your experience is very much appreciated. I will check that out and titrate as she is about 40 kg.
So do you think the Mg Threonate's mechanism of action is primarily mediated by the threonic acid vs. the availability of the Magnesium? Both obviously would have a positive effect on glutamate metabolism, but it would seem a large enough dosage of something like Mg Glycinate would do the same, if it were truly the mineral and not the amino acid. I will have to look into this myself, just wondering if you have any thoughts on this.
In this regard do you have any particular reaction to Vitamin C, especially a highly bioavailable form, since threonic acid can be metabolized from ascorbic acid.