Got Mg problems too.... Simply can not get adequate amounts from food (done on purpose). Soils are depleted or too low (done on purpose). Then there's all kinds of pollution that saps it (all done on purpose as well). Plus a healing body needs more than normal anyway.
Oral magnesium supplements are ineffective (absorption rate far too low compared to Mg content, and eating more of it is pointless health wise and money wise). Unless Mg is in ionic form, as it is in oceans and seas naturally.
Magnesium oxide absorption rate can be as low as 4%.
Magnesium Chloride baths should be the easiest and best health and money wise, should be somewhat more effective than epsom salt (another Mg salt). The salt in water goes into ionic form, so Mg ions and Cl ions, both of which your body needs. Mg is best absorbed through skin.
Already a hundred years ago some doctor used (supposedly) Mg Chloride solution for cleaning wounds, and noticed that in comparison to other liquids that not just didn't work but made things even worse, MgCl2 effectively cleaned the wound and accelerated healing (that's what I read). Then began testing it for many many other illnesses.
What you are definitely still missing in adequate amounts is Mg. You urinate most of it back out.
Vitamin B6 supposedly plays a role in metabolizing Mg.
There's two kinds of MgCl2, one is industrial grade - you don't want that... the other is for living things.
Find a supplier and try the salt, If works then good.
www.ancient-minerals.com Sells it, but might be able to get cheaper from somewhere else.
Haven't yet tried it myself (have to get it first), hopefully in the next two weeks, or rather
definitely in the next two weeks. What I've read suggests it is one of the most effective ways of getting Mg, because of its ionic form in water.