Experts say it's difficult to restore a serious magnesium deficiency without supplements. Because Magnesium is essential to every bodily system, supplementing can often have profound effects. This page shows you:
What makes a magnesium supplement effective? How readily it gives our body the magnesium ion: the lone, positively charged magnesium atom. Why?
This is why when we take a supplement in which magnesium is part of a molecule, our body has to separate the magnesium ion from the molecule in order to use it. Now, because magnesium in nature and in supplements is always found attached to at least one other atom or molecule, several factors should be kept in mind about supplements:
Now let us look at the four categories of magnesium supplements and then at the molecular forms of magnesium on the market which fall into 4 categories:
Trans-dermal/topical magnesium supplements pass through our skin instead of our intestine, avoiding two problems in oral supplements:
Trans-dermal magnesium has helped people for centuries in the form of epsom salt baths (magnesium sulfate). New magnesium chloride topical supplements achieve the same effect when we spray them on our skin.
Magnesium mineral salts can be extracted naturally or made synthetically. They are the smallest forms because the magnesium is only attached to a few atoms, as opposed to large molecules such as amino acids which have 20 atoms. As an example, magnesium chloride is 1 magnesium ion with 2 chloride ions. (An ion is simply an atom with an electric charge.)
The most common mineral salts are magnesium-chloride, -sulfate and -oxide. Others include magnesium-bicarbonate, -carbonate, -hydroxide and -phosphate. Magnesium chloride and sulfate can also be used as transdermal supplements – above. This is because “transdermal” is a classification of how the magnesium supplement is absorbed, rather than a classification of its physical molecular properties.
Magnesium acid complexes are synthetically made when magnesium is mixed with an acid – a compound made of hydrogen, oxygen, carbon, and nitrogen.
Their stability constant is the measure of how easily our body extracts the magnesium ion for us to use. The lower the stability constant, the more bio-available the magnesium ion is. The best possible stability constant is ZERO, because it means the body gets the magnesium ion without doing any work.
Magnesium citrate, aspartate and glutamate should be avoided because their acids can become toxic to our cells. (Section 3 covers this.)
These synthetic supplements contain magnesium bound to larger molecules called amino acids (the building blocks which comprise proteins). They include magnesium glycinate, -lysinate, -orotate, -taurate and -threonate.
Because our intestine has special pathways for amino acids to pass through, these supplements should have superior absorption into our bloodstream, with practicaly no laxative effect. However the research that amino acid chelates enter our blood stream at higher rates than other magnesium supplements needs further development.
[Mineral Salt] Magnesium chloride is both a mineral salt and can be used as a transdermal supplement. It also has several benefits.
1. Amount of magnesium: Because it comes from a small molecule of only one magnesium atom and two chloride atoms, the magnesium makes up a greater % of the molecule than all the acid/amino acid supplements.
2. It gives us the magnesium ion: In terms of the human body, it’s the magnesium ion that we need for our vital processes, and the magnesium chloride ion consists of a magnesium ion and 2 chloride ions.[1-3]
3. Bioavailability: The magnesium chloride molecule is actually a magnesium ion hovering around two chloride ions. The stability constant of the bond between the magnesium and chloride ions is zero. Thus our body gets the magnesium ion without having to waste any energy.
4. Cellular absorption: Inside our cells is where we need magnesium the most. Because magnesium chloride gives us the ion, it can enter our cells easily via their magnesium ion channels[1,3]. When magnesium is bound to large molecules like amino acids, it can’t pass through these channels. Furthermore, if the large molecule does manage to enter our cells, is it able to detach from the magnesium so we can use it? If so, at what cost of energy?
5. Vitality: Energy production is the single most vital process of any living being. It keeps us alive, and supports all other vital processes. Magnesium chloride helps with insulin production and function[4,5], helping our cells absorb fuel and improving our metabolic profile.
6. Versatile use: Magnesium chloride is now being used as a transdermal (topical) supplement to help increase absorption by avoiding the gut. While the exact mechanism of absorption is not yet understood, it is known that absorption does in fact take place, and it has also been shown to more specifically help those suffering from fibromyalgia. 
7. Added chloride benefits: The chloride ions in magnesium chloride are critical for stomach function, bacterial control, and are essential electrolytes our body needs for energy balance. It’s important not to consume excess because balancing chloride with the other electrolytes is still important.
[Amino Acid Complex] Magnesium orotate is magnesium bound to two orotic acid molecules. It has good bio-availability and has been studied for several benefits including heart health.
Orotates aid cardiovascular health by increasing RNA and DNA synthesis of heart cells, and stimulating their energy (ATP) production. Their roles inside our cells explain why magnesium orotate has good cellular absorption. It has also been shown to improve several different heart conditions in rats (very similar in DNA to humans) and exercise tolerance in human patients with coronary heart disease.
Out of all the acid and amino acid complexes, magnesium orotate is being shown to be the most effective, especially for cardiovascular health.
[Amino Acid Complex] Also known as magnesium di-taurate, this larger molecule whose elemental mass is 9% magnesium, also contains two taurine molecules. While showing promise in aiding depression, taurine is also involved in cardiovascular health, the development of our neuromuscular system, as well as the function of our antioxidant systems.
Magnesium taurate is suggested to help with cardiovascular health (vascular protection and myocardial infarction), pregnancy (pre-eclampsia, eclampsia, perinatal asphyxia), mental health (migraines), and type 2 diabetes insulin resistance.
(People who take insulin for type 2 diabetes should consult their doctor before using magnesium taurate because of its ability to enhance insulin sensitivity. Diabetics taking magnesium taurate may experience drastic blood sugar swings which can be lethal.)
[Amino Acid Complex] Magnesium glycinate also known as magnesium bisglycinate is a combination of magnesium oxide with two glycine amino acids. Glycine is known for its calming affects and magnesium glycinate has been shown to help with chronic back pain and severe depression.
Magnesium glycinate is currently the most popular amino acid chelate available. While glycine can pass through our intestine without stimulating a laxative effect, no research has been done to show it has superior absorption into our cells than other forms of magnesium. Also in some individuals the glycinate may convert to glutamate or oxalates which may not be ideal. Having said that, magnesium glycinate still shows measurable benefits and promise.
[Amino Acid Complex] Magnesium threonate is the newest magnesium supplement, comprised of magnesium and the amino acid l-threonine. Preliminary research on rats has shown it can deliver high amounts of magnesium to the central nervous system, in some cases even reversing advanced Alzheimer’s. One recent study has replicated similar results in humans, with another also showing improvements in memory deficits.
People looking to maintain good mental and nervous system function can use magnesium l-threonate, however caution is advised for those taking Alzheimer’s medications because RxList and WebMD both have strong warnings about L-Threonine’s interactions with these drugs. Also there is some concern that threonine might decrease lung function in patients with Lou Gherig’s disease.
[Mineral Salt] Magnesium sulfate is mostly known as an epsom salt used in magnesium-restorative baths. Like magnesium chloride, it can act topically and orally, however it has a stronger laxative effect than most forms which limits how much is absorbed orally.
While larger than magnesium chloride, it is still one of the smaller forms of magnesium, containing 1 magnesium atom out of every 6 atoms, with an additional sulfur atom, and 4 oxygen atoms in each molecule.
While most effective as an epsom salt bath, it is also used intravenously for pregnant mothers to manage eclampsia and pre-eclampsia, which is where the bulk of magnesium sulfate research has been done. The sulfur in magnesium sulfate is also critical for our cells’ detoxification, as well as heart, mental, and metabolic health.
[Mineral Salt] Magnesium oxide is the smallest molecule of all the supplements, comprised of only 1 magnesium atom and 1 oxygen atom. Most commonly found in milk of magnesia products for its highly laxative effects, it has been shown to have very poor absorption at only 4%. 
However recent analysis of these findings may be pointing towards a different picture: magnesium oxide may simply stay in our gut longer, meaning it enters our system long after the times typically used to measure its absorption.
While resolving deficiency with magnesium oxide is not practical due to the small frequent doses needed to avoid its strong laxative effect, milk of magnesia is quite possibly the safest and healthiest form of constipation relief available to humans.
The molecule also shares a key benefit with magnesium chloride: its magnesium is in ionic form and thus more readily available to our cells once it enters our bloodstream.
[Acid Complex] Magnesium malate consists of a magnesium atom bound to malic acid. Malic acid is an essential nutrient needed for human energy metabolism, and aluminum detoxification. This – along with its reported pain reducing effects – helps explain the Texas Health Science Center’s preliminary results showing magnesium-malate’s beneficial effects on patients with Fibromyalgia, a condition characterized by low energy levels and high pain sensitivity.
Magnesium malate helps with fibromayalgia, however people sometimes report side effects attributed to malic acid including muscular pain, nausea, swollen skin, milt to extreme chest pain, and tightness, and allergic reactions that interfere with breathing. While the net result seems to be positive, care is advised in using this supplement.
[Mineral Salt] Magnesium hydroxide consists of magnesium bound to two hydroxide molecules (hydrogen and oxygen).
Taking this supplement is not recommended because it is very poorly absorbed via the intestinal tract, and can draw large amounts of water into it from the surrounding tissues by osmosis, which may contribute to defecation.
[Acid Complex] This molecular combination of magnesium and citric acid has become popular due to a study showing its superior absorption to magnesium oxide, as well as its calming effect, and ability to relieve constipation. Yet a closer look at this supplement shows several reasons why it may be toxic.
Many people even report their magnesium RBC tests showing drops in cellular magnesium levels after taking magnesium citrate for several months. This again falls in line with the study showing that magnesium citrate increases our levels in the serum, not our cells.
Overall, for the purposes of restoring the body’s healthy magnesium levels, magnesium citrate is not recommended.
[Amino Acid Complex] While magnesium aspartate is said to have superior absorption, and has been shown to improve fatigue and muscular hyper-excitability, both magnesium aspartate and glutamate in high doses should be avoided due to the potentially toxic effects of the aspartate and glutamate molecules.
Both aspartate and glutamate, once separated from the magnesium ion, are excitatory neurotransmitters. These chemical messengers can potentially stimulate our brain and nerve cells to the point of injury or death if taken in high concentrated doses. This is why using magnesium aspartate and glutamate to resolve magnesium deficiency is not advised.