When you take one element or the other, the way to maximize it is to take the co-factors too. That's why people here keep saying to do it via whole foods- all the co-factors are there. It's a question though of if you are low on the one or the other- there's many stories of finding the one thing that's missing, and having a joyful moment of relief and surprise!
Calcium (1:1 ratio or less calcium, more magnesium when there is any muscle tension)
Potassium (trouble sleeping/restlessness or heartbeat feeling delayed is when you are saturated and it is time for potassium, like from organic unsulfered molasses)
zink (drives mercury out of effected cells, causes contaminated-cell dieoff so that the healthy new cell can replace it)
selenium (Involved in maintaining healthy nerves, denaturing mercury, and in the process of making glutathione)
b-complex vitamins (nurtures neurons alongside magnesium, both are needed especially for the CNS. These also detoxify and nurture the liver)
boron (strengthens bones, drives flouride and bromine from bodily tissues, prevents the spillage of magnesium and calcium from the kidneys)
Hair analysis is not a reliable way to say for certain if your intracellular magnesium levels are optimal- only a tissue sample does that.
One of the most powerful examples of magnesium's importance is the testimonies of folk re-whitening their teeth by using magnesium-oil for oil-pulling- whitening happens within 3-4 months in optimal circumstances (no amalgams, clean diet). Bones are meant to be rich repositories of it, and teeth are some of the places you can really see the state of your bones (discoloured enamel).
Your body, however, no matter what it's state, is secondary to your spirit. You can be as crunky as dishwater after thanksgiving on the outside, but bouncing-bright on the inside- so set your eyes on heaven, and ther won't be any worries for you, just new joys!