There are several different types of Magnesium (Mg) on the market. The difference is the amino acid used to bind Mg and how it is absorbed in your body. The most common and least expensive type is Magnesium oxide.
Mg oxide: least bio-available (absorbed by the body), but still provides some benefits for constipation, Mg deficiency, muscle cramping, migraines, sleep problems, lowers blood pressure and reduces stomach acid. Sometimes you can get this in liquid form or powdered form to make a fuzzy drink. I usually recommend
Calm Mg (powdered), Blubonnet(liquid) or TwinLabs(capsule) in the 400 mg capsule taken twice a day. You know you have reached a thereapeutic dosage when you have a loose, comfortable stool. If you’ve gone to the point of having diarrhea, back off on the dosing.
Mg Citrate: this type is used most often for constipation or bowel prep before having a colonoscopy.
Mg Chelate: highly absorbably by the body and the kind found naturally in foods. The chelation process also makes this a little more pricy, but you get more bang for your buck.
Mg Chloride: usually used as an oil to be used topically for those people who have digestive disorders or for use directly on the muscles that are hurting. Ancient Minerals has an effective oil/spray.
Mg Glycinate: highly absorbable in the body (bioavailability) and least likely to have a laxative effect.
Mg Bis-glycinate is most effective and popular, and relatively more expensive than the others mentioned.
Mg Threonate: highly bioavailable and proven to penetrate the mitochondrial membrane inside the cell. Mitochondria are the powerhouse of every cell in your body. This type is also used for enhancing memory and cognitive function, such as Neuro-Mag by Life Extension.
Mg Orotate: researched to be the most beneficial to the heart.
Mg Taurate: using Taurine for heart health and protection.
Mg Malate: useful for energy production associated with fibromyalgia, chronic fatigue, etc.
Mg Sulfate: used in hospitals in intravenous (IV)form to lower blood pressure such as pre-ecclampsia, stroke, migraine. Mg sulfate is also commonly known as Epsom Salts, which help when used with soaking in a hot bath for muscle aches and pains.
According to the National Institutes of Health (NIH), testing the levels of magnesium through a blood test is not an accurate assessment of Mg in the body. This is because most of the magnesium is not found in the blood, but in the tissues that use Mg the most: bones, muscles, organs, inside the cells. A more accurate assessment for Mg deficiency would be to measure serum Mg concentration in the blood or measuring concentrations in saliva or urine. By the time Mg deficiency has shown on a blood test, it has already been leeched out of the bones, muscles and organs of the body.
Mg deficiency is often based upon clinical presentation such as muscle cramping, high blood
pressure, poor sleep, constipation, history of migraine headaches, etc.
Magnesium results are best when taken at night, just before bed, or in divided dosing such as morning and night.