Re: magnesium, anxiety, dehydration...

 Be careful.

I just found out the hard way that you can take too much magnesium with Adrenal Fatigue and hypothyroidism

http://emedicine.medscape.com/article/246489-overview#showall

Hypothyroidism, adrenal insufficiency, milk-alkali syndrome^{[3, 4]} and theophylline intoxication occasionally produce mild elevations of serum magnesium

I was taking 1500 mg per day via magnesium oil, which turned out to be way to much.  As shown in the article, it creates hypo-calcium for those who can't clear the excess magnesium.  

This is how it showed up for me, I started to get hypo-calcium symptoms.  Hypermagnesium suppresses the parathyroid hormone, thereby creating hypocalcium.

http://www.nejm.org/doi/full/10.1056/NEJM198405103101904 

Another lesson I learned the hard way.  !

So yes....people with adrenal fatigue need magnesium.   But it appears that we can't handle an excessive amount like normal people.  

So we almost need to take the exact amount for our needs, without going over too much.  Not easy.  All you can do is pay attention to symptoms, keep a good log book and adjust.