Magnesium is needed for more than 300 biochemical reactions in the body. It helps maintain normal muscle and nerve function, keeps heart rhythm steady, supports a healthy immune system, and keeps bones strong. Magnesium also helps regulate blood sugar levels, promotes normal blood pressure, and is known to be involved in energy metabolism and protein synthesis. There is an increased interest in the role of magnesium on preventing and managing disorders such as hypertension, cardiovascular disease, and diabetes.
Magnesium is the second most prevalent electrolyte in the body, yet over two-thirds of us get less than the minimum recommended 400 mgs per day. Most of us get about half that much. Note that 400 mgs is just enough to keep us from feeling the major deficiency symptoms. Optimal health may require 600 to 1000 mgs per day. 
Only 12% of American take magnesium supplements and multivitamins are almost never a good source.
Best Forms of Magnesium
there are many forms of magnesium available as supplements. All magnesium is mined as minerals from the earth. However, the mineral is bonded or chelated to various organic or inorganic substances to increase absorption and bioavailability. Different forms of magnesium have varying levels of magnesium concentration,
Organic Forms: glycinate, bisglycinate, lysinate, citrate, malate, aspartate, gluconate, threonate, and lactate.
Generally, the organic forms are much better absorbed and better tolerated by the gut because they increase the body's ability to recognize and absorb the mineral. Inorganic forms are cheaper, not as well absorbed, and act as laxatives, but have higher magnesium concentration.
Magnesium Glycinate and Bisglycinate
These are probably the best forms. with bisglycinate providing more glycine for added absorption and additional relaxation and detoxification benefits. There is no laxative effect. The disadvantage here is that these forms have low magnesium concentration, requiring higher number of pills per day.
Magnesium Malate
Very well absorbed with no laxative effects. It has been shown to help people who suffer from fatigue. Helps balance stomach acid as well.
Magnesium Threonate
Very well absorbed. This new form has been shown to cross the blood-brain barrier to proved magnesium benefits to the brain. Other forms of magnesium may also provide the same benefits to the brain, but threonate is the only one with some proof.
Magnesium Rich Foods
Green leafy vegetables such as spinach, nuts, seeds, unsweetened cocoa, ,dried seaweed, dried coriander, and dried basil.
