What is it?

Magnesium is technically a metal (Mg 2+) and you may remember it from being one of the elements on the periodic table. The evidence of one of the first commercial products relating to the health effects of magnesium is a patent for Milk of Magnesia that was filed in 1873 (1), which was marketed to help patients with constipation. It was called “milk” because of the whitish appearance that the dissolved magnesium gave the solution. Original Milk of Magnesia was 8% Magnesium hydroxide and was marketed as a laxative. (2) Magnesium was eventually recognized as an essential nutrient in 1925, and has since been discovered to be the 4th most prominent mineral in the body after calcium, potassium, and sodium.

How is it made?

As a mineral, magnesium isn’t made, but sourced from ocean water (magnesium chloride) or mined from the Earth (magnesium oxide). Magnesium is rarely found as a free element since the non-oxidized form of it is very volatile and reacts vigorously with oxygen. This process creates a large flash, so much so that it’s used to create the effects of fireworks. Magnesium is commonly mined or sourced from oceans close to China, North Korea, Russia, Austria, Greece, and the USA.(3)

Foods grown in environments rich in magnesium will also become high in magnesium themselves. Most of the magnesium that we eat comes from vegetables, but often grains and prepared food products can be augmented with magnesium as well. Similar to how commercial breakfast cereals have lots of vitamins and minerals added to them (almost making them multivitamins), magnesium also gets added to foods to make sure that we eat enough magnesium.

The other most prominent source of magnesium is in soil and is transferred to the foods we grow in the soil. Magnesium levels in food have declined an average of 20% compared to 75 years ago. In large part due to industrial farming practices. By farming the same crops in the same soil over and over again, the soil itself is starting to diminish in mineral content, which is having a clear impact in the food that is grown in that overused soil.(4) This is, in turn, impacting the quantity of magnesium in our bodies, which can have significant health effects.

magnesium supplements

In which forms is it available?

When it comes to dietary supplements, magnesium can be found in several forms that can be grouped into 3 categories: inorganic salts, organic salts, and amino ccid chelates.

When magnesium is listed as an ingredient in a dietary supplement, the content will always be the amount of elemental magnesium, and not the entire chemical structure of the ingredient that it’s bound to. This makes it easy to compare total magnesium content of products, since all products are using the same standard of description.

When an atom of magnesium is bound to other atoms that don’t have any carbon in them, these are called “inorganic salts”. These are typically the lowest cost because they are readily found in nature and don’t take much money or effort to produce. They tend to have a strong laxative effect compared to other forms of magnesium, because of how much water they draw into the intestines, leading to loose stools.

Here are some common forms of inorganic salts:

  • Magnesium Oxide
  • Magnesium Hydroxide
  • Magnesium Sulphate
  • Magnesium Chloride

If an atom of magnesium is bound to a molecule that contains carbon, it’s called an “organic salt”. In this case, the “organic” doesn’t mean that it’s grown without pesticides. These forms of magnesium offer moderate tissue bioavailability while still having an osmotic effect on stools to provide a mild laxative effect.

Here are some common forms of organic salts:

  • Magnesium Citrate
  • Magnesium Malate

“amino acid chelates” are molecules where the magnesium is bound to an amino acid (the building block of proteins). These magnesium molecules are the best absorbed in the gut, because they move easily across the membrane of the intestines through special protein transporters that are specifically designed for amino acids.

Here are some common forms of amino acid chelates:

  • Magnesium Bisglycinate (glycinate)
  • Magnesium Taurate
  • Magnesium Threonate
  • Magnesium Orotate

Magnesium supplements are available in powders, capsules, tablets, and liquids. Since magnesium is water soluble and has a fairly benign taste, it’s one supplement that can be taken in many different forms without compromising its efficacy. Unlike vitamin D, which should be taken with a fatty meal, magnesium supplements can be taken anytime.

How does it work?

Magnesium’s first use was for its laxative properties. It actually works differently than other laxatives that are on the market. Magnesium is what we call an “osmotic laxative”, which means that it works by drawing water into the colon so that stool is better hydrated and softer. This is contrary to how two other common forms of laxatives work:

  • Stimulating laxatives cause colon irritation with makes the intestines get more active and move the stool;
  • Stool softeners actually change the chemical composition of the stool to make it easier to pass.

Magnesium is one of the most gentle laxative agents and has the least associated side effects compared to other forms of laxatives.

It can also help to relax muscles in the body because it opposes calcium, which helps muscles contract. Muscle contraction is initiated when calcium atoms are released into the muscle, but it takes the release of magnesium atoms to initiate complete muscle relaxation. Without sufficient magnesium, the muscle can stay in a hypertonic state that leaves people feeling tight and result in a higher rate of muscle cramps.

Magnesium is a cofactor is in over 300 biochemical reactions required to maintain normal body functioning. Some of the biological functions of magnesium include having an effect on building DNA, creating the base form of energy (ATP), regulating blood sugar through insulin release, and helping brain hormone chemistry.(5)

magnesium blood pressure supplements

Benefits of Magnesium

Adequate levels of magnesium are associated with a lower risk of cardiovascular disease and death from cardiovascular events through decreasing blood pressure and helping to relax the cardiac muscle. There are very few supplements that can consistently lower the risk of heart disease and death from cardiovascular disease. Magnesium, vitamin D, and omega 3 intake from fish oil are the three supplements that can aid in the long-term prevention of these diseases.(6)

Magnesium can be used on the skin as well. Epsom salts (Magnesium sulfate) are the most common form of topical application of magnesium, but there are also sprays, salves, and creams that impart some of the same effects. They are named after the region where they were discovered: Epsom, England, which is only a few minutes Southwest of London. While recent research has not been conclusive about the effects of Epsom salts on muscle relaxation (with researchers challenging whether magnesium sulfate can cross the skin), there has been a history of use that confirms that patients feel well after bathing in a tub with Epsom salts. There are even magnesium-containing hot springs that carry rich histories of positive health effects as well.

Oral magnesium can help with muscle cramping on a physiological basis of muscle contraction, and opposing the calcium levels in the muscle.(7) Partly related to its effects on muscle, and partly related to its effects on stress and pain sensation, Magnesium has also been shown to be a preventive treatment for migraines with minimal side effects compared to other treatments.(8)

Magnesium is used intravenously or it can be inhaled to treat childhood asthma. It acts as an anti-inflammatory agent in the lungs and can also help widen children’s airways. Magnesium supplementation resulted in shorter hospital stays and a lower dependence on inhalers after the children were discharged from the hospital.(9) Adults taking oral asthma were also able to benefit from improved quality-of-life scores, as well as a decreased dependence on their inhalers.(10)

Finally, magnesium has been shown to benefit patients with anxiety and stress-related disorders. This effect was first discussed when it was observed that urinary magnesium levels increased in situations of high stress. This led to further studies where it was discovered that magnesium may attenuate stress-related disorders by modifying the stress response and the function of cortisol in the body. 11)

Are there side effects?

Magnesium is generally well-tolerated when used in appropriate doses. Some clinical research shows no differences in adverse effects between placebo and magnesium groups. Orally, magnesium can cause gastrointestinal irritation, nausea, vomiting, and diarrhea. High doses can also increase risk of neonatal mortality and neurological defects.

When there is ample research available about particular vitamins and minerals, it’s possible to develop Tolerable Upper Intake Levels (UL), which are the maximum daily intake that have been shown to cause adverse health effects. These upper intake levels came into effect in 1997 when the dietary reference intake (RDI) ranges were developed, and the research was done in a time when magnesium salts were the only products readily available on the market. At that time, a 350mg dose of a magnesium salt was sure to cause a high likelihood of loose stools as a side effect. Today, a 350mg dose of a magnesium chelate has a much lower chance of causing such side effects due to of its increased bioavailability.(7)

Most Recommended on Fullscript

Magnesium Glycinate

Magnesium Glycinate Complex by Klaire Labs

For optimal absorption, this formulation uses magnesium combined with amino acid glycine to create a unique chelated compound that is highly bioavailable and well tolerated by even the most sensitive individuals.


Magnesium (glycinate) 120 mg by Pure Encapsulations

Magnesium (glycinate) is a highly bioavailable magnesium chelate, which supports the metabolism and utilization of carbohydrates, amino acids and fats for energy. Magnesium (glycinate) helps activate enzymes for physiological functions including cardiac health.

Mag Glycinate by Metagenics

Mag Glycinate by Metagenics

Mag Glycinate features a magnesium amino acid chelate (bis-glycinate) designed to enhance absorption and intestinal tolerance. Unlike other formulations, the magnesium in Mag Glycinate is designed to be absorbed via a mechanism similar to that used by amino acids and unlike typical mineral ion absorption.

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  1. Wolf, Marshall A. “President’s Address: Mother Was Right: The Health Benefits of Milk of Magnesia.” Transactions of the American Clinical and Climatological Association, vol. 117, 2006, pp. 1–11.
  2. “Genuine Phillips’ Milk of Magnesia”. https://doi.org/10.1007/s11104-013-1665-5.
  3. “Magnesium | Minerals Education Coalition.” Minerals Education Coalition, https://mineralseducationcoalition.org/elements/magnesium/.
  4. Guo, Wanli, et al. “Magnesium Deficiency in Plants: An Urgent Problem.” The Crop Journal, vol. 4, no. 2, 2016, pp. 83–91.
  5. Swaminathan, R. “Magnesium Metabolism and Its Disorders.” The Clinical Biochemist. Reviews / Australian Association of Clinical Biochemists, vol. 24, no. 2, May 2003, pp. 47–66.
  6. Del Gobbo, Liana C., et al. “Circulating and Dietary Magnesium and Risk of Cardiovascular Disease: A Systematic Review and Meta-Analysis of Prospective Studies.” The American Journal of Clinical Nutrition, vol. 98, no. 1, July 2013, pp. 160–73.
  7. Supakatisant, Chayanis, and Vorapong Phupong. “Oral Magnesium for Relief in Pregnancy-Induced Leg Cramps: A Randomised Controlled Trial.” Maternal & Child Nutrition, vol. 11, no. 2, Apr. 2015, pp. 139–45.
  8. Holland, S., et al. “Evidence-Based Guideline Update: NSAIDs and Other Complementary Treatments for Episodic Migraine Prevention in Adults: Report of the Quality Standards Subcommittee of the American Academy of Neurology and the American Headache Society.” Neurology, vol. 78, no. 17, Apr. 2012, pp. 1346–53.
  9. Davalos Bichara, Marcela, and Ran D. Goldman. “Magnesium for Treatment of Asthma in Children.” Canadian Family Physician Medecin de Famille Canadien, vol. 55, no. 9, Sept. 2009, pp. 887–89.
  10. Kazaks, Alexandra G., et al. “Effect of Oral Magnesium Supplementation on Measures of Airway Resistance and Subjective Assessment of Asthma Control and Quality of Life in Men and Women with Mild to Moderate Asthma: A Randomized Placebo Controlled Trial.” The Journal of Asthma: Official Journal of the Association for the Care of Asthma, vol. 47, no. 1, Feb. 2010, pp. 83–92.
  11. Boyle, Neil Bernard, et al. “The Effects of Magnesium Supplementation on Subjective Anxiety and Stress-A Systematic Review.” Nutrients, vol. 9, no. 5, Apr. 2017, doi:10.3390/nu9050429.

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