Magnesium supplements come in many forms, each with their own levels of absorption, side-effects and effectiveness. Learn about the different molecular forms of magnesium supplements below.
++ Page Overview
Our muscles, nerves, genes and organs all require magnesium. This is why magnesium is perhaps the most important supplement. This review of magnesium supplements includes:
- What makes a good magnesium supplement: Ion delivery.
- The 4 types of supplements. (topical, mineral salts, acid & amino acid complexes)
- A brief look at 11 different molecular forms of magnesium supplements.
While magnesium is our most vital substance, other chemicals in magnesium supplements also exert their own effects on our body. This guide reveals transdermal magnesium chloride as a good base for a safe magnesium restoration routine, and magnesium orotate, taurate, glycinate and/or threonate as beneficial complimentary supplements for added metabolic, cardiovascular and mental/nervous support.
++ Helpful tip
If you’re busy or want to understand things better, please read each section’s quick summary.
1. What makes a good magnesium supplement:
The magnesium ion:
What makes a magnesium supplement effective? How readily it gives our body the magnesium ion: the lone, positively charged magnesium atom. Why?
- Apart from its role as an electrolyte in the fluid outside our cells, all the vital magnesium-dependent processes that keep us alive and healthy, happen inside our cells.
- The magnesium ion is what our cells use for these vital processes.
- The magnesium ion is also the form of magnesium that most easily enters our cells.
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:
- How easily and how much of the magnesium ion do we absorb from the supplement?
- What percentage of the supplement is magnesium vs other molecules?
- The nature of the other molecules in the supplement: how good are they for us?
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 these 4 categories).
What makes a good supplement?
How easily it gives us the magnesium ION, instead of magnesium lodged in a bigger molecule.
2. The four categories of supplements:
To absorb nutrients into our bloodstream, we must first break them down into small enough parts to pass through our intestinal wall. Trans-dermal/topical magnesium supplements pass through our skin instead of our intestine, avoiding two problems in oral supplements:
- Magnesium’s laxative effect on our intestine at certain doses.
- The average human’s poor digestive/intestinal health and function.
Trans-dermal magnesium has helped people for centuries in the form of epsom salt baths (magnesium sulfate). New magnesium chloride topical supplements have emerged to 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. As an example, magnesium chloride is 1 magnesium ion with 2 chloride ions.
The most common mineral salts are magnesium-chloride, -sulfate and -oxide. Others include magnesium-bicarbonate, -carbonate, -hydroxide and -phosphate. Notice the overlap: magnesium chloride and sulfate can also be used as transdermal supplements.
This is because “transdermal” is a classification of how the magnesium supplement is absorbed, rather than a classification of it’s physical molecular properties (whcich is what categories 2, 3 and 4 are based on).
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. You can see which magnesium compound has the perfect stability constant on our magnesium chloride page, or see it in the next section.
Magnesium citrate, aspartate and glutamate should be avoided because their acids can become toxic to our cells. (Section 3 covers this.)
Amino acid complexes
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 have superior absorption into our bloodstream, with practicaly no laxative effect. However to date there exists limitted research that amino acid chelates enter our blood stream at higher rates than other magnesium supplements.
Ο Mineral salts (magnesium chloride, sulfate, and oxide) are the smallest molecules. The first two can be used transdermally & orally.
Ο Magnesium acid complexes are synthetically made by joining magnesium with acids. Some acids are toxic.
Ο Magnesium amino acid complexes are magnesium bound to an amino acid. Inestinal absorption is good but cellular absorption not fully known. A few of these make great complimentary supplements to magnesium chloride.
3. The different molecular forms of magnesium:
We review 11 of the most readily available magnesium supplements in order of their safety and effectiveness:
Transdermal magnesium chloride: Good for rapid whole-body magnesium restoration.
Magnesium orotate, magnesium taurate, magnesium glycinate, magnesium l-threonate: Decent options. Good for complimentary use alongside magnesium chloride. For various specific uses including metabolic, mental and cardiovascular health.
Magnesium sulfate, magnesium oxide, magnesium malate, May have benefits under specific circumstances, but absorption issues and side-effects are mentioned.
Magnesium hydroxide, magnesium citrate, magnesium aspartate and magnesium glutamate: NOT RECOMMENDED because of potential toxicity and side effects of the additional molecules attached to the magnesium.
++ Magnesium Chloride (natural, effective, ionic)
[Mineral Salt] Magnesium chloride is the safest and most reliable magnesium supplement, for several critical reasons:
1. Amount of magnesium: Because it comes from a small molecule of only one magnesium atom and two chloride atoms, magnesium from magnesium chloride makes up a greater % of the molecule than all other acid/amino acid supplements.
2. It gives us the magnesium ion: The ionic form of a mineral/atom is the one in which the atom is on its own with an existing charge (positive or negative). In terms of the human body, it’s the magnesium ion that we need for our vital processes.[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 spending 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.
++ Magnesium Orotate (heart, cellular absorption)
[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.
++ Magnesium Taurate (heart, brain, insulin warnings)
[Acid Complex] Also known as magnesium ditaurate, 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.)
++ Magnesium Glycinate (calming, mood)
[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 can have toxic effects in the body.
++ Magnesium L-Threonate (mental benefits)
[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
++ Magnesium Sulfate (baths & pregnancy)
[Mineral Salt] Magnesium sulfate is mostly known as 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, 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.
++ Magnesium Oxide (absorption issues)
[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.
++ Magnesium Malate (fibromyalgia, side effects)
[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.
++ Magnesium Hydroxide (intestinal issues)
[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.
++ Magnesium Citrate (potentially toxic)
[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 is toxic.
- Magnesium citrate’s calming effect is misleading. Studies show it increases magnesium in the blood serum, not in the cells. Of course rapid rises of electrolytes in our serum have calming and energizing effects. This simply suggests magnesium citrate has poor cellular absorption, thus remaining in the bloodstream and increasing serum levels.
- Citric acid taken in excess contributes to the erosion of our bones and teeth.
- Most importantly, citrate leads to the toxic buildup of iron in our cells and organs by damaging and interfering with the enzyme ceruloplasmin , whose main function is to prevent iron from building up in our cells by load it into our hemoglobin.
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.
++ Magnesium Aspartate & Glutamate (potentially toxic)
[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 should be avoided due to the toxic effects of the aspartate and glutamate molecules.
Both aspartate and glutamate, once separated from the magnesium ion, are exicatory 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.
- Magnesium Selective Ion Channels. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2084240/
- The Magnesium Miracle (Revised and Updated). https://www.amazon.ca/Magnesium-Miracle-Revised-Updated/dp/034549458X
- The structure and regulation of magnesium selective ion channels.https://www.ncbi.nlm.nih.gov/pubmed/23954807
- Magnesium improves the beta-cell function to compensate variation of insulin sensitivity: double-blind, randomized clinical trial. (While magnesium’s role in the beta cell’s actual release of insulin is less established than its role in the beta cells creating insulin, this study makes ground on the overall impact of magnesium on beta cells). http://www.ncbi.nlm.nih.gov/pubmed/21241290
- Oral magnesium supplementation improves insulin sensitivity in non-diabetic subjects with insulin resistance. A double-blind placebo-controlled randomized trial. https://www.ncbi.nlm.nih.gov/pubmed/15223977
- Oral magnesium supplementation improves the metabolic profile of metabolically obese, normal-weight individuals: a randomized double-blind placebo-controlled trial. https://www.ncbi.nlm.nih.gov/pubmed/24830937
- Effects of transdermal magnesium chloride on quality of life for patients with fibromyalgia: a feasibility study. https://www.ncbi.nlm.nih.gov/pubmed/26343101
- Magnesium orotate–experimental and clinical evidence. http://www.ncbi.nlm.nih.gov/pubmed/16366126
- Magnesium orotate in myocardial and neuronal protection. http://www.ncbi.nlm.nih.gov/pubmed/15523949
- Metabolic supplementation with orotic acid and magnesium orotate. http://www.ncbi.nlm.nih.gov/pubmed/9794088
- Effects of magnesium orotate on exercise tolerance in patients with coronary heart disease. http://www.ncbi.nlm.nih.gov/pubmed/9794089
- Rapid recovery from major depression using magnesium treatment. http://www.ncbi.nlm.nih.gov/pubmed/16542786
- Complementary vascular-protective actions of magnesium and taurine: A rationale for magnesium taurate. http://www.medical-hypotheses.com/article/S0306-9877(96)90007-9/abstract
- Magnesium taurate for the prevention and treatment of pre-eclampsia/eclampsia. http://www.medical-hypotheses.com/article/S0306-9877(96)90065-1/abstract
- Magnesium taurate and fish oil for prevention of migraine. https://www.ncbi.nlm.nih.gov/pubmed/8961243
- Rapid Resolution of Chronic Back Pain with Magnesium Glycinate in a Pediatric Patient. http://www.omicsgroup.org/journals/rapid-resolution-of-chronic-back-pain-with-magnesium-glycinate-in-a-pediatric-patient-2167-0846.1000101.php?aid=3932
- Elevation of brain magnesium prevents synaptic loss and reverses cognitive deficits in Alzheimer’s disease mouse model. https://www.ncbi.nlm.nih.gov/pubmed/25213836
- Efficacy and Safety of MMFS-01, a Synapse Density Enhancer, for Treating Cognitive Impairment in Older Adults: A Randomized, Double-Blind, Placebo-Controlled Trial. https://www.ncbi.nlm.nih.gov/pubmed/26519439
- Magnesium L-threonate prevents and restores memory deficits associated with neuropathic pain by inhibition of TNF-α. http://www.ncbi.nlm.nih.gov/pubmed/24077207
- Threonine: Are there any interactions with medications? http://www.rxlist.com/threonine-page3/supplements.htm
- THREONINE OVERVIEW INFORMATION. http://www.webmd.com/vitamins-supplements/ingredientmono-1083-THREONINE.aspx?activeIngredientId=1083&activeIngredientName=THREONINE
- Therapeutic Uses of Magnesium. http://www.aafp.org/afp/2009/0715/p157.html
- Bioavailability of US commercial magnesium preparations. http://www.ncbi.nlm.nih.gov/pubmed/11794633?dopt=Abstract
- Treatment of fibromyalgia syndrome with Super Malic: a randomized, double blind, placebo controlled, crossover pilot study. http://www.ncbi.nlm.nih.gov/pubmed/8587088
- Mg citrate found more bioavailable than other Mg preparations in a randomised, double-blind study. http://www.ncbi.nlm.nih.gov/pubmed/14596323
- Proof for the Ascorbate Oxidase Activity of Ceruloplasmin. http://www.jbc.org/content/239/10/3570.full.pdf
- On the mechanism of citrate inhibition of ceruloplasmin ferroxidase activity. http://www.ncbi.nlm.nih.gov/pubmed/8696078
- THE MITIGATION OF PHYSICAL FATIGUE WITH “SPARTASE”. REP 63-12. http://www.ncbi.nlm.nih.gov/pubmed/14133531