What is Magnesium and what does it do in the body?

Magnesium is an essential macromineral that makes up 0.05% of our body weight. It is involved in several hundred enzymatic reactions contributing to the production of energy, the cardiovascular system, and the nervous system. Magnesium was originally named after the Greek city Magnesia where large deposits of magnesium carbonate were found. It was first used as a laxative, which is still one of its many uses today. 

About 65% of the magnesium in our bodies is located inside the bones and teeth. The bones act as a storehouse of magnesium during times of need. The other 35% of magnesium in the body is located in the blood, fluids, and other tissues; the brain has a higher concentration of magnesium than the blood, and there is also a significant amount of magnesium present in the heart. 

The process of magnesium digestion and absorption is similar to that of calcium. The ratio of intake for these minerals is about 2:1 calcium to magnesium. Magnesium requires an acidic stomach environment for optimal absorption, so it is best taken between meals or at bedtime. Meals high in protein or fat, a diet high in phosphorus or calcium, or alcohol use may affect magnesium absorption.

Normally, about 40-50% of the magnesium we take in is absorbed, but this could vary from 25-75% depending on stomach acid levels, your body’s needs, dietary habits, and the exact form of magnesium. Stress can increase magnesium excretion, the kidneys can excrete or conserve magnesium according to the body’s needs, and the intestines can eliminate excess magnesium in the feces. 

Magnesium has many functions in the body. It is considered to be the “anti-stress” mineral due to its natural tranquillizing effect of relaxing skeletal muscles as well as smooth muscles in the blood vessels and the gastrointestinal tract. Magnesium’s presence in the heart may help to prevent coronary artery spasm, which is a significant cause of heart attacks. The optimal function of the blood vessels requires a balance of magnesium, calcium, phosphorus, potassium, and sodium chloride. For example, with low magnesium in the body, more calcium can flow into the cells of the vascular muscle, which contracts these cells and can lead to tighter blood vessels and higher blood pressure; thus magnesium in the body can help prevent high blood pressure. 

 

 

 

Magnesium is primarily located inside the cells. It activates enzymes needed for protein and carbohydrate metabolism, as well as for DNA production and function. It also modulates electrical potential across cell membranes to allow nutrients to pass back and forth. It helps with energy release by transferring the key phosphate molecule to adenosine triphosphate (ATP), which is the energy molecule generated by the cytochrome system in the body. Magnesium can also sit at the entrance to nerve cell calcium channels to help prevent overstimulation of the cells due to an excess of calcium in the body. It can also help dilate blood vessels. 

Magnesium also is involved in glucose metabolism. Magnesium plays a critical role in cell division, it regulates the movement of potassium in myocardial cells, it is needed to create glutathione, it is needed for vitamin D metabolism, and is necessary for the synthesis and secretion of parathyroid hormone. It also is involved with calcium in the formation of the hard tooth enamel to prevent tooth decay. 

 

What are some causes of magnesium deficiency?

Magnesium deficiency is a very common thing especially in America today with around 70-80% of us deficient in Magnesium. Decreases in magnesium intake have been more prevalent in America with the additions of supplemental vitamin D and calcium, dietary phosphorus, and refined/processed carbohydrate foods. Additionally, drinking soft water decreases magnesium intake, while diuretic drugs, alcohol, caffeine, and sugar all cause magnesium loss. People who cook or boil all their foods and do not consume the water they are boiled in are more likely to have magnesium deficiency. 

Deficiencies are more common when magnesium absorption is decreased, including after burns, serious injuries, and surgery as well as in people with diabetes, liver disease, and malabsorption issues. As discussed above, deficiency is also possible when magnesium elimination is increased, including in people who use alcohol, caffeine, eat an excess amount of sugar, or who take diuretics or birth control pills. 

 

 

 

Magnesium works closely together with Vitamin D, calcium, and phosphorus. In the current processed food supply, there is an artificial abundance of vitamin D added into milk and dairy products, added phosphorus in the form of phosphoric acid added to soft drinks, and extra calcium added into many processed foods. There is little to no added magnesium into processed foods, thus part of the current trend of magnesium deficiency may be due in part to false elevations of other nutrients in the processed food supply. 

Decreased levels of magnesium in the body can lead to high blood pressure, kidney stones, heart disease, and heart attacks due to coronary artery spasms. Studies have found that a decreased concentration of magnesium is found in the heart and blood of people who have had a heart attack. Additionally, magnesium deficiency has also been shown to be linked to premenstrual syndrome (PMS). 

 

 

 

Early symptoms of magnesium deficiency include fatigue, anorexia, irritability, insomnia, muscle tremors, and muscle twitching. Psychological changes that can accompany these symptoms include apathy, apprehension, decreased luring ability, confusion, and poor memory. Moderate deficiency can lead to tachycardia and other cardiovascular changes, while severe deficiency can lead to numbness, tingling, and tetany of the muscles as well as delirium and hallucinations. 

What is Magnesium used for?

Magnesium is used in numerous treatments and for numerous reasons in the body. In the heart and cardiovascular system, magnesium can be used in the prevention or treatment of myocardial infarctions, relieving certain kinds of angina, reducing the risk of coronary artery spasms that can lead to angina or heart attack, in the prevention or treatment of hypertension, reducing the symptoms of mitral valve prolapse including palpitations and arrhythmias, and helping in cardiac arrhythmias such as atrial tachycardia or fibrillation. 

Magnesium can be helpful for people with osteoporosis since magnesium is important for bone mineralization. Studies on post menopausal women have shown an increase in bone density in women who supplemented with magnesium for 6-18 months. 

 

 

 

Magnesium may be useful in reducing bronchoconstriction in asthma by relaxing the muscles around the bronchial tubes. It has also been used intravenously during acute asthma attacks. 

Magnesium can be used to lower blood pressure in women with preeclampsia. It may also be helpful in reducing epileptic seizures caused by nerve excitability due to its nerve and muscle relaxant effects. 

It can be helpful for preventing kidney stones, particularly calcium oxalate stones, by increasing calcium solubility especially in the urine. Additionally,  calcium oxalate stones are most likely to form in people who are magnesium deficient, so treatment may include remedying the magnesium deficiency. Magnesium is also helpful in preventing calcification of other tissues and blood vessels due to its ability to increase calcium solubility. 

 

 

 

Magnesium can be helpful in symptoms relating to menstruation as well. Supplementing with magnesium has been shown to help alleviate many symptoms related to the menstrual period. Menstrual cramps, irritability, fatigue, depression, and water retention have all been shown to be lessened by magnesium. Magnesium is often at its lowest level during menstruation, so many symptoms of PMS can be remedied by replenishing the body with magnesium. For this purpose, it is often supplemented along with calcium and vitamin B6. 

Fatigue can also be improved with magnesium. Magnesium is required by many enzyme systems that help restore normal energy levels. Due to this function as well as its support of nerves and muscles, magnesium may also be helpful for nervousness, anxiety, insomnia, depression, and muscle cramps. 

Magnesium is typically used in treatment for autism, ADHD, and hyperactivity in children. Children with ADHD have been found to have low serum magnesium levels and their behavior improved when administered magnesium supplements. Magnesium can be helpful for inducing a good night sleep when taken before bed. As Magnesium Malate, magnesium can be helpful for chronic fatigue syndrome and fibromyalgia pains. Magnesium may also reduce lead toxicity and buildup possibly through competing for absorption. 

Magnesium is a key part of nutritional support for diabetes because like chromium, magnesium is involved in glucose metabolism. More than half of all diabetics show evidence of magnesium deficiency and supplementing magnesium may prevent some of the complications of diabetes such as retinopathy and heart disease. Magnesium supplementation has been shown to improve the insulin response and its action in the body, glucose tolerance, and the fluidity of the red blood cell membrane in diabetic patients. 

 

 

 

Due to its effect on insulin, magnesium may also be supportive for people with polycystic ovarian syndrome (PCOS). 

Magnesium may support people with glaucoma because it has been called “nature’s physiological calcium-channel blocker” and calcium channel blockers have been shown to benefit some glaucoma patients. Studies showed that magnesium supplementation improved peripheral circulation and the field of vision in glaucoma patients. 

Magnesium may also be helpful for people that suffer from migraines. Studies have shown a link between low magnesium levels and both migraine and tension headaches. Magnesium has been shown to prevent migraines specifically in people with low levels of magnesium. 

Magnesium may be used as part of a natural support for tinnitus symptoms. It can be helpful in protecting against noise damage in the ear and in preventing muscle spasms. To read more about Tinnitus, check out our blog post: Tinnitus. 

What are food sources of magnesium?

Food sources of magnesium mainly come from vegetables, but seafood also contains fairly high amounts of magnesium. Since the central atom of the chlorophyll structure is magnesium, it is important to plant photosynthesis and thus is found in high amounts in dark green vegetables. Nuts, seeds, legumes, and soy contain high amounts of magnesium. Whole grains including wheat, millet, and brown rice are high in magnesium and fruits such as avocado and dried apricots are other good sources. 

 

 

 

Many factors can influence the availability of magnesium in foods. One factor is the amount of magnesium in the soil in which the food is grown. Magnesium can be lost in the processing and refining of foods as well as in the process of making oils from magnesium-rich nuts and seeds; nearly 85% of magnesium in grains is lost during the milling of flours. Soaking and boiling foods can also cause the magnesium to leach into the water, so it is recommended to consume the water in which foods are cooked in since it is rich in magnesium and other minerals. Oxalis acid in vegetables like spinach and chard and phytic acid in some grains can form insoluble salts with magnesium, which can cause it to be eliminated rather than absorbed. Because of these factors and many more, many people do not get enough magnesium from their diet and they most likely need to supplement to get the amount of magnesium their body requires. 

What are the available forms of magnesium?

The available forms of magnesium consist of magnesium chelated with various amino acids or organic acids in order to increase absorption. 

Magnesium oxide has a 4-20% absorption rate and 60% magnesium. This form is mostly used as a laxative, but it has low bioavailability. For Magnesium oxide, check out Magnesium Oxide Douglas. 

Magnesium sulfate has a 30-50% absorption rate and 9.9% magnesium. Magnesium sulfate is also known as epsom salt and it is normally used in baths for muscle relaxation.

Magnesium glycinate is the form where magnesium is attached to the amino acid glycine. It has a 90-95% absorption rate and the magnesium content is 16.2%. This form is very bioavailable, and tends to be used when you want more of the relaxing benefits of magnesium because the amino acid glycine has a relaxing effect on the body. It is also the form recommended for migraines. For Magnesium glycinate, we recommend Magnesium Glycinate Arcana, Magnesium Glycinate Pure, and Mag Glycinate Metagenics. If you are interested in a powder form, you can try Magnesium Bisglycinate Powder Thorne. 

Magnesium citrate is the form of magnesium bound to citric acid. It has a 80-90% absorption rate and the magnesium content is 14.1%. This form is used most often for digestion and constipation because the citric acid has a stimulating effect on the bowels. For Magnesium citrate, we recommend Magnesium citrate Pure, Magnesium citrate SFI Health, and Magnesium citrate Metabolic Maintenance. 

Magnesium orotate is a form of magnesium that is attached to orotic acid. It has a 50-60% absorption rate and 31.6% magnesium. This form is typically used to support heart health. It supports heart function and cellular energy. For this form of magnesium, try Magnesium Orotate Priority One. 

Magnesium lactate is derived from lactic acid. It has a 50-60% absorption rate and 12% magnesium. This form is easily absorbed and gentle on the stomach. It also helps to promote cellular energy production. For Magnesium Lactate, try Magnesium Lactate Standard Process. 

Magnesium Malate is magnesium bound to malic acid. It has a 70-80% absorption rate and 11.8% magnesium. This form is used often for fibromyalgia and chronic fatigue syndrome because the malic acid helps with energy production and muscle function. It is also the form of magnesium typically recommended for restless leg syndrome. For magnesium malate, try Magnesium Malate Integrative Therapeutics. 

Magnesium taurate is made from combining magnesium with taurine. It has a high absorption rate and has 25% magnesium. This form is good for circulation and cardiovascular health and may help support healthy blood sugar regulation. For Magnesium taurate try Magnesium Taurate Cardiovascular Research in 60c and 180c. 

Magnesium L-Threonate is a form of elemental magnesium that can cross the blood brain barrier. That is why this form is recommended for brain health and cognitive function. One study found that Magnesium L-Threonate has neuroprotective properties and may promote synaptic plasticity, which is important for the integrity of the central nervous system. For Magnesium L-Threonate try NeuroMag Life Extension.

When comparing the amount of magnesium you can get from these different types of magnesium according to the magnesium content and absorption rate, you need to calculate the amount of magnesium and then multiply that by the absorption rate. For example, if you had 100mg of magnesium glycinate, you would have 16.2mg of magnesium using the 16.2% magnesium content and 90-95% of that would be absorbed, so 14.58-15.39 mg of magnesium. 

What are contraindications of magnesium?

Taking magnesium may interfere with those taking blood pressure medications or calcium channel blockers. People with kidney disorders or those taking insulin injections should consult with their doctor before taking magnesium. Magnesium may interfere with the absorption of antibiotics, and antiarrhythmic drugs. It is contraindicated with  Levothyroxine, some drugs used for osteoporosis, potassium-sparing diuretics, loop diuretics, foscarnet, azathioprine, amino glycosides, amphotericin B, cisplatin, beta blockers, corticosteroids, aluminum laxatives, prednisone, and warfarin. It may be contraindicated for those with myasthenia gravis and for those with a very slow heart rate. 

What are the side effects of taking magnesium?

If calcium intake is low, symptoms of magnesium toxicity can occur including depression of the central nervous system, muscle weakness, fatigue, sleepiness, and irregular heartbeats, low blood pressure, and hyper excitability. Magnesium may also cause loose stools. Large doses could cause stomach pains, nausea, and diarrhea. 

 

 

References

 

Berg, Eric. (2025, April 9). Best Types of Magnesium- Uses, Benefits, and Risks. Dr. Berg. https://www.drberg.com/blog/the-best-and-worse-types-of-magnesium 

Calatayud, Kevin. (2025, Mar 6). Which types of magnesium is best? Miye. https://www.miye.care/en/which-type-of-magnesium-is-best/

Haas, E.M. (2006). Staying Healthy with Nutrition: The Complete Guide to Diet and Nutritional Medicine: 21st Edition. Ten Speed Press. 

Hechtman, Leah. (2019). Clinical Naturopathic Medicine: Second Edition. Elsevier. 

Murray, M.T. & Pizzorno, J. (2021). Textbook of Natural Medicine: Fifth Edition. Elsevier. 

Murray, M.T. & Pizzorno, J. (2012). The Encyclopedia of Natural Medicine: Third Edition. Atria. 

Ramirez, AJ. (2012, Sep 21). Magnesium Contraindications. Ancient Minerals. https://www.ancient-minerals.com/magnesium-contraindications/ 

WiseOwl Health. (2024, November 14). Magnesium Supplements guide: 20+ Forms & Absorption Rates Compared. Wise Owl Health.  https://wiseowlhealth.com/blogs/health-wellbeing/magnesium-absorption