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20 Magnesium Benefits + Side Effects, Dosing, Sources

Written by Biljana Novkovic, PhD | Last updated:
Jonathan Ritter
Puya Yazdi
Medically reviewed by
Jonathan Ritter, PharmD, PhD (Pharmacology), Puya Yazdi, MD | Written by Biljana Novkovic, PhD | Last updated:

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Magnesium

Magnesium is an essential nutrient that helps improve gut health, prevent eclampsia, and potentially improve a wide variety of health conditions. Is there enough in your diet? Find out here.

What is Magnesium?

Magnesium is the fourth most abundant mineral found in our body [1]. It is essential to all living cells and vital for numerous physiological functions [2].

Magnesium is required for the production of ATP (the main source of energy in our cells) [3], and the production of DNA, RNA, and proteins [4].

Magnesium plays an important role in cell-to-cell communication [5].

Over 300 enzymes require the presence of magnesium to function properly [3].

Because of its positive charge, magnesium stabilizes the cellular membranes [2].

Magnesium is important for:

  • bone health [6]
  • muscle contraction and relaxation [5, 7]
  • heart rhythm and blood pressure [6]
  • stabilizing blood glucose levels, and regulating sugar and fat metabolisms [6, 8]
  • neurotransmitter production and regulation [5]
  • neural function [6]
  • the immune system [6]

Magnesium Deficiency

Magnesium deficiency is rare. Early signs include nausea, vomiting, and weakness; chronic deficiency may have long-term complications [9].

Pancreatitis

Nutritional magnesium deficiency increases the susceptibility of the pancreas towards disease, by elevating calcium concentrations. Elevated calcium is an established risk factor for pancreatic inflammation (pancreatitis).

Magnesium administration reduced pancreatic enzyme activities, tissue swelling and death, and inflammation during pancreatitis in rats [10].

Kidney Decline

Low magnesium is associated with increased risk of death and kidney function decline in chronic kidney disease patients as well as mortality in dialysis patients [3].

Cisplatin, a commonly used chemotherapeutic for ovarian and other cancers, reduces magnesium levels in most patients and causes acute kidney injury in 25-30% of patients.

Magnesium supplementation during cisplatin treatment protects against cisplatin-mediated acute kidney injury in mice [11].

Additionally, magnesium supplement therapy was significantly associated with both reduced frequency and reduced severity of kidney toxicity in patients receiving cisplatin [12].

Snapshot

Proponents:

  • Essential nutrient easily sourced from food
  • Relieves constipation
  • Reduces gastric acidity
  • Prevents eclampsia
  • Important for heart and bone health
  • May help prevent headaches
  • May prevent insulin resistance
  • Many other potential health benefits

Skeptics:

  • High doses required for some benefits
  • Can cause loose stools if you take too much

Health Benefits of Magnesium

Effective

1) Constipation

Magnesium salts are considered effective laxatives for relieving constipation. They are also considered safe for children [13].

2) Dyspepsia

Magnesium salts can also be used as antacids, which effectively reduce the acidity in the stomach [14].

3) Pregnancy

Magnesium is considered an effective treatment for pre-eclampsia and eclampsia during pregnancy [15].

Gestational magnesium deficiency may cause developmental defects [16].

Magnesium supplementation resulted in a lower incidence of newborn jaundice and newborn hospitalization [17] and reduced the risk of low birth weight [16].

Women receiving magnesium were significantly less likely to require hospitalization during pregnancy [18].

Magnesium supplementation among women with pregnancy-induced diabetes had beneficial effects on metabolic status and pregnancy outcomes [17].

The transfer of large amounts of magnesium from the mother’s blood to the fetus with other nutrients may contribute to the occurrence of post-pregnancy depression (by causing magnesium deficiency in the mother) [19].

Likely Effective For

4) Cardiovascular Function

Magnesium is required for the normal electrical activity of the heart, and has beneficial effects on the cardiovascular system, by widening blood vessels, improving fat metabolism, reducing inflammation, and inhibiting blood platelet aggregation.

Low magnesium and experimental restriction of dietary magnesium increase cardiac arrhythmias. Abnormally low circulating magnesium is associated with an increased incidence of cardiac arrest [20, 21].

Magnesium is used as a first-line therapy for torsades de pointes, a type of arrhythmia of the heart [14].

An increase in circulating magnesium was associated with a 30% lower risk of cardiovascular disease, while dietary magnesium was associated with a 22% lower risk of ischemic heart disease.

Increased consumption of magnesium-rich foods, such as whole grains, nuts, and vegetables has been estimated to lower the risk of cardiovascular mortality by 28% [22].

Self-reported magnesium intake was inversely associated with the hardening of the arteries (calcification), which may play a contributing role in magnesium’s protective associations in stroke and fatal heart disease [23].

Possibly Effective For

5) Bone Health

Lower magnesium intake is associated with lower bone mineral density and promotes osteoporosis [2].

In postmenopausal women, low magnesium intake has been correlated with more rapid bone loss or lower bone mineral density [24]. Magnesium supplementation was beneficial in osteoporotic women [25].

On the other hand, elevated magnesium may have a harmful effect on bone metabolism and parathyroid gland function, leading to mineralization defects [26].

Magnesium excess (5 – 10 times nutrient requirements) in rats had no effect on bone mineral density in short-term but lowered bone mineral density in long-term studies [24].

Bone lesions and lower bone mineral density were recorded in cases of acute exposure to high-dose magnesium in humans. Magnesium consumption slightly greater than the RDA was associated with increased lower-arm and wrist fractures that were possibly related to more physical activity and falls [24].

6) Diabetes and Insulin Resistance

Low magnesium levels play a role in the development of insulin resistance. Nondiabetic patients with low serum magnesium are significantly more likely to have insulin resistance, glucose intolerance and elevated insulin levels compared to patients with higher magnesium levels.

Low magnesium has been implicated in the cause of liver disease, especially non-alcoholic fatty liver disease and nonalcoholic steatohepatitis. Both conditions are strongly associated with insulin resistance, as well as obesity, type 2 diabetes, elevated fat levels and high blood pressure [27].

Magnesium was inversely associated with metabolic syndrome [28], and oral magnesium supplementation improved the metabolic profile and lowered the blood pressure of metabolically obese and normal-weight individuals [29].

In the study, blood pressure, insulin resistance, fasting glucose and triglyceride levels all decreased significantly in the subjects who received Magnesium chloride compared with individuals who didn’t [29].

Lower magnesium intake was associated with a higher risk of diabetes in the Taiwanese population [30].

Greater magnesium intake was associated with a lower risk of type 2 diabetes and metabolic abnormalities [31].

Increased consumption of magnesium-rich foods such as whole grains, beans, nuts, and green leafy vegetables may reduce the risk of type 2 diabetes [32].

Evidence suggests that insulin sensitivity, elevated blood sugar, type 2 diabetes and elevated fat content in the blood can be improved with increased magnesium intake [33].

7) Fibromyalgia

In multiple clinical trials, supplemental magnesium significantly reduced the pain associated with fibromyalgia [34, 35].

8) Headaches and Migraines

Magnesium deficiency can lead to brain artery spasm and increased the release of pain substances (such as substance P). Significantly lowered serum magnesium levels have been seen in migraine and tension headache sufferers.

A high dose (600 mg) of oral magnesium daily for 12 weeks significantly reduced the frequency of headaches by 41.6%, and also reduced the severity, drug usage, and duration of the acute attacks [5].

Magnesium supplements, along with routine treatment, significantly improved all migraine indicators [36].

9) Chronic Fatigue Syndrome

Stress hormones, including both catecholamines and corticoids, can cause a reduction in tissue magnesium levels. Many of the symptoms and findings in chronic fatigue syndrome resemble those of magnesium deficiency. A referral center that evaluated several hundred chronic fatigue syndrome patients observed that half of their patients were magnesium-deficient [37].

Chronic fatigue syndrome patients who are magnesium deficient benefit from an injection of 580 mg magnesium [37, 38].

10) Hearing Loss

Magnesium intake acts synergistically with antioxidants to prevent hearing loss [39].

11) Asthma

Multiple studies have found that single, high doses of magnesium can relieve symptoms of asthma, especially in children. It is unclear whether taking magnesium supplements has any particular benefit to asthma; talk to your doctor before supplementing for this reason [40, 41].

12) Metabolic Syndrome

In multiple clinical trials, people who ate high-magnesium diets were significantly less likely to develop metabolic syndrome. It is unclear whether supplemental magnesium might have the same effect [42, 43].

13) Premenstrual Syndrome

In multiple clinical trials, magnesium supplements reduced water retention, poor mood, and migraines associated with menstruation [44, 45, 46].

Insufficient Evidence For

The following purported benefits are only supported by limited, low-quality clinical studies. There is insufficient evidence to support the use of magnesium for any of the below-listed uses. Talk to a doctor before using magnesium supplements, and do not use them in place of something a doctor recommends.

14) Blood Pressure

Magnesium supplementation has led to reductions in blood pressure of up to 12 points (mmHg) [47, 33].

Magnesium increases the effectiveness of all drug classes that reduce blood pressure [33] and additionally decreases high blood pressure in patients on blood pressure-lowering medications [48].

15) Anxiety and OCD

In a clinical trial, magnesium supplementation reduced anxiety and anxiety-related disorders when used in combination with other vitamins, minerals and herbal extracts [49].

Magnesium helps suppress the HPA axis (CRH, ACTH, Cortisol) [50].

Magnesium relieved premenstrual anxiety in women, when taken together with B6 [49].

Partial magnesium-depletion increased anxiety-related behavior in mice [51].

Patients with OCD were found to have lower magnesium [52].

Magnesium’s anti-anxiety role is mediated in large part by its ability to block NMDA receptors [50].

16) Depression

Magnesium plays a role in many of the pathways involved in depression and is found in several enzymes, hormones, and neurotransmitters [53].

Mice consuming a diet with very low magnesium content-consisting of only 10% of the daily requirement-showed depressive behavior [51].

Low magnesium status has been associated with increased depressive symptoms in several different age groups and ethnic populations [53].

Major and suicidal depression particularly seems to be related to magnesium insufficiency [19].

Magnesium supplementation has been linked to improvements in symptoms of major depression, premenstrual symptoms, postpartum depression, and chronic fatigue syndrome [53].

Administration of magnesium sulfate to rats subjected to traumatic brain injury significantly decreased both incidences of post-traumatic depression and its severity [19].

Co-treatment of magnesium salts and antidepressants from different classes (i.e., fluoxetine, imipramine, and bupropion) resulted in the synergistic antidepressant-like effect [19].

Case studies of magnesium supplementation reported improvements in depression, anxiety, and sleep within one week. Surprisingly, in one study, low magnesium intake in older adults seemed to protect from depression [53].

17) ADHD

Reduced serum levels of magnesium were found in patients with ADHD. Psychostimulants increased serum magnesium levels in ADHD after 3 weeks of treatment [54].

Magnesium supplementation may be beneficial in treating attention-deficit/hyperactivity disorder (ADHD).

18) Skin Allergies

Magnesium deficiency impairs immunity. Topical and oral administration of magnesium salts had beneficial effects in patients with skin allergy [55].

19) Inflammation

Magnesium sulfate (Epsom salt) exposure before preterm birth is neuroprotective, reducing the risk of cerebral palsy and major motor dysfunction.

In pregnant mothers, magnesium sulfate reduced maternal TNF and IL-6 production and substantially reduced the frequency of the baby’s monocytes producing TNF-α and IL-6 under stimulated conditions [56].

Magnesium plays a critical regulatory role in Nf-kB activation [57].

The immunomodulatory effect was mediated by magnesium rather than sulfate, and it was reversible [56].

20) Aging

Several pieces of evidence link low Magnesium to aging and age-related diseases. Studies have shown that cultures in low magnesium (Mg) accelerates the death of human endothelial cells and fibroblasts [58].

Magnesium inadequacy interferes with cellular metabolism, which could affect this process.

Mitochondrial and Antioxidant Function

Magnesium in the mitochondria accounts for one-third of total cellular magnesium [59]. Magnesium forms a complex with ATP, which is an important source of stored energy.

A large portion of the energy used in humans is produced by mitochondria through the movement of electrons over the respiratory chain.

Magnesium is critical for basic mitochondrial functions, including ATP synthesis, electron transport chain complex subunits, and oxygen detoxification [60].

Inadequate availability of magnesium may lead to reduced mitochondrial efficiency and increased production of reactive oxygen species with consequent structural and functional impairment to proteins, DNA, and other essential molecules.

Studies of magnesium-deficient cultured human cells and animals show evidence of decreased antioxidant capacity and mitochondrial swelling in magnesium-deficient animals [61].

Hence, magnesium seems fundamental for the control of oxidative stress and to maintain the normal function of mitochondria.

Cancer Research

Magnesium deficiency exacerbates chronic inflammatory stress and may play a role in the onset of cancer. Middle-aged men with higher serum magnesium concentrations had a 50% lower risk of cancer death than those with low serum magnesium [4].

Magnesium intake may be beneficial in terms of primary prevention of pancreatic cancer. Every 100 mg per day reduction in magnesium intake was associated with a 24% increase in the incidence of pancreatic cancer [62].

Magnesium Deficiency

Low consumption of magnesium is common throughout the world [1].

Dietary magnesium intakes among most American adults are low. A study estimated the magnesium intake from food sources to 261 mg in women and 347 mg in men, which is well below the RDA (320 mg for women and 420 mg for men) [22].

Low magnesium levels in the body may occur due to defects in its absorption or as a result of its loss via kidneys (in case of diabetes, alcoholism, treatment with antidiuretics, aminoglycosides, fluoroquinolones, cisplatin, digoxin, cyclosporine, amphotericin B).

Acute emotional stress and stressful activities increase magnesium excretion/loss [19].

Magnesium excretion increases while absorption decreases with age, because of various chronic diseases and decreased intake of foods high in magnesium [53].

Elderly women may be more susceptible to magnesium deficiencies than men, partly because they are more likely to have osteoporosis, which limits the exchange of magnesium between bone and blood [63].

Magnesium deficiency produces a variety of neuromuscular and psychiatric symptoms such as hyperexcitability, agitation, tetany (involuntary muscle contractions), headaches, seizures, ataxia, vertigo, muscular weakness, tremors, irritability, anxiety, insomnia, nervous fits, faintness, fatigue, confusion, hallucinations, and depression [19].

Severe dietary magnesium restriction has a detrimental effect on metabolism, glucose balance, and retention and excretion of other minerals [22].

Side Effects, Sources, and Bioavailability

Too much magnesium can also cause loose stools and “make you go.”

In patients with chronic renal failure or in individuals undergoing dialysis, serum magnesium concentrations are frequently elevated and correlate with mineralization defects [2].

Chronic high dietary magnesium exposure causes potential thyroid disruption [64].

Magnesium can sometimes potentially increase GSK3b, a problematic protein, but this can be inhibited by lithium [65].

Sources

Major food sources containing magnesium are leafy green vegetables, fruits, legumes (especially soy), nuts (almonds, cashews), whole grains, red meat, and seafood [5, 4].

Consumption of these foods can easily elevate magnesium levels [53].

Magnesium-containing supplements are generally well-tolerated with very few reported side effects [49]. Side effects include gastrointestinal upset such as nausea, vomiting, or diarrhea in some people [53].

Bioavailability and Dosing

Not all supplements of magnesium are readily absorbed [5].

Organic forms of magnesium like aspartate, citrate, lactate, fumarate, acetate, ascorbate and gluconate have greater solubility and bioavailability in comparison to inorganic forms like oxide, sulfate, chloride, and carbonate [47].

A magnesium chelate such as magnesium citrate is considered safe at doses up to 600 mg per day in adults [5].

Evaluation of both circulating and dietary magnesium is important because circulating magnesium reflects not only diet but also gastrointestinal absorption and renal regulation [22].

High doses (>10mg/kg/d) of magnesium can be toxic [54].

About the Author

Biljana Novkovic

Biljana Novkovic

PhD
Biljana received her PhD from Hokkaido University.
Before joining SelfHacked, she was a research scientist with extensive field and laboratory experience. She spent 4 years reviewing the scientific literature on supplements, lab tests and other areas of health sciences. She is passionate about releasing the most accurate science and health information available on topics, and she's meticulous when writing and reviewing articles to make sure the science is sound. She believes that SelfHacked has the best science that is also layperson-friendly on the web.

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