The human body contains large amounts of the element magnesium. Magnesium is involved in more than 300 chemical reactions. The first reported medicinal use of magnesium occurred in the 17th Century, after a farmer found that well water, which contained magnesium sulfate, had soothing and healing properties when applied to the skin. Since then, Epsom salts, which contain magnesium sulfate, have been commonly applied to the skin and added to baths. Magnesium salts in various forms have been used for centuries as laxatives.
Magnesium sulfate has a long history of use for the treatment of pre-eclampsia (high blood pressure and excess protein in the urine) and eclampsia (a toxic condition that can lead to seizures) in pregnant women.
Studies on magnesium have shown it to be effective for the treatment of acute childhood asthma. Some studies have also shown benefit from magnesium for the treatment of several heart disorders, chronic obstructive pulmonary disease (COPD), type 2 diabetes, hearing loss, leg cramps during pregnancy, and side effects from the drug succinylcholine (a neuromuscular blocker). At higher doses, magnesium may control high blood pressure, although study findings are unclear.

Related Terms

Chelated magnesium, Emgesan®, Epsom salts, magnesia, magnesium aluminum sulfite, magnesium aspartate, magnesium carbonate, magnesium chloride, magnesium citrate, magnesium diglycine, magnesium disuccinate hydrate, magnesium gluconate, magnesium glycerophosphate, magnesium glycinate, magnesium hydroxide, magnesium lactate, magnesium malate, magnesium murakab, magnesium orotate, magnesium oxide, magnesium phosphate, magnesium pidolate, magnesium salicylate, magnesium sulfate, magnesium sulphate, magnesium trisilicate, milk of magnesia, Slo-Mag®, Super Malic®.

evidence table

These uses have been tested in humans or animals. Safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider.
Pre-eclampsia (and eclampsia) (Grade: A)
Pre-eclampsia (high blood pressure and excess protein in the urine) and eclampsia (a toxic condition during pregnancy that can cause seizures) are common problems of pregnancy that can lead to serious complications and death. Healthcare professionals commonly inject magnesium sulfate into the veins in cases of pre-eclampsia and eclampsia. Magnesium sulfate is considered a superior drug for the prevention of the recurrence of seizures in eclampsia and for seizure prevention in pre-eclampsia. A common, but not serious, side effect of magnesium sulfate therapy is flushing (reddened skin, especially on the neck and cheeks).
Arrhythmia (irregular heartbeat) (Grade: B)
Irregular heartbeats are the most common complications after heart surgery. Magnesium injected into the vein has been reported to reduce irregular heartbeats (e.g., atrial fibrillation and cardiac arrhythmias). However, it was not found to affect the length of hospital stay, the incidence of heart attack, or death.
Asthma (Grade: B)
Asthma can frequently worsen and range from mild to severe attacks. The use of magnesium sulfate is one of many treatment options available during acute asthma attacks. Magnesium sulfate administered in the vein, or with a nebulizer combined with other asthma therapies, has been shown to be effective for the treatment of acute asthma attacks, particularly in children with severe symptoms. However, magnesium is not as effective for mild-to-moderate attacks.
Diabetes (type 2) (Grade: B)
Type 2 diabetes is often preventable through diet and exercise, as obesity is a major factor in its development. Magnesium taken by mouth has been reported to reduce the risk of developing type 2 diabetes and to improve blood sugar control in type 2 diabetic patients. Other than a modest decrease in blood pressure, magnesium supplementation was found to have only a small impact on other important endpoints associated with diabetes complications.
Hearing loss (Grade: B)
The benefits of magnesium taken by mouth have been investigated in cases of hearing loss caused by noise or an unknown cause. Magnesium treatment has been shown to reduce temporary and permanent hearing loss caused by noise. To date, it is not clear how magnesium benefits hearing loss.
Neuroprotection (for premature infants) (Grade: B)
Premature delivery may result in many adverse effects in infants, including blindness, deafness, cerebral palsy, and other major disabilities. A systematic review suggests that magnesium sulfate during pregnancy may improve motor function in early childhood for infants born prematurely and may reduce the risk of development of cerebral palsy.
Acute myocardial infarction (heart attack) (Grade: C)
Magnesium injected into the veins has been reported to reduce arrhythmia (irregular heartbeat), which commonly occurs during a heart attack. It is unclear whether magnesium therapy injected into the vein reduces the number of deaths caused by heart attacks. Magnesium is an alternative therapy for patients who are not able to take traditional therapies for the treatment of a heart attack.
Alcohol withdrawal (Grade: C)
Intramuscular administration of magnesium as a supplement to benzodiazepines showed no significant difference in the severity of withdrawal symptoms. Additional high-quality clinical research is needed in this area.
Cardiac arrest (loss of heart function) (Grade: C)
Cardiac arrest is a life-threatening event in which the heart stops contracting properly. Because of an apparent benefit of magnesium for heart attack, it has been used together with other agents for cardiopulmonary resuscitation (CPR). However, it is unclear whether magnesium is the ideal treatment choice for CPR, due to conflicting scientific study findings. Additional high-quality clinical research is needed in this area.
Chronic obstructive pulmonary disease (COPD) (Grade: C)
Chronic obstructive pulmonary disease (COPD) is a progressive lung disease in which the airways become narrowed. The greatest risk factor for COPD is smoking. Acute attacks of COPD are commonly seen and difficult to treat. Administration of magnesium sulfate into the vein after beta-agonists (drugs that help with breathing) was found to be safe and modestly effective in the treatment of acute flare-ups of COPD. This combination was more effective than beta-agonist therapy alone. More high-quality clinical research is necessary to draw a conclusion.
Coronary artery disease (heart disease) (Grade: C)
Experimental evidence has suggested that magnesium may play a beneficial role in regulating the formation of blood clots. A clinical study showed that taking magnesium by mouth inhibits formation of blood clots in stable patients with coronary artery disease (heart disease). Additional research is needed in this area.
Fibromyalgia (Grade: C)
Fibromyalgia is a disorder that causes chronic widespread pain and a painful response to gentle touch. Other features include marked fatigue, sleep disturbance, and joint stiffness. A small study found that Super Malic® (containing malic acid and magnesium) may be beneficial for this condition. Additional research is needed to confirm early findings.
Hemorrhage (Grade: C)
Magnesium infusion reduced the risk of poor outcome and delayed cerebral ischemia in patients with aneurysmal subarachnoid hemorrhage. Additional research is needed to confirm available research results.
High blood pressure (Grade: C)
It is unclear whether oral magnesium supplementation can lower blood pressure in patients with mild-to-moderate high blood pressure or prevent the onset of high blood pressure. Higher doses of magnesium are associated with a decrease in blood pressure to very low levels. Several studies have reported a small and not significant decrease in blood pressure with magnesium. Further research is needed on the use of magnesium in the treatment of high blood pressure.
Kidney stones (Grade: C)
In an analysis of two studies, there was a lack of benefit from magnesium on recurrent calcium stone formers. Further research is needed on the use of magnesium in the treatment of kidney stones.
Leg cramps (during pregnancy) (Grade: C)
Leg cramps are a common problem during pregnancy, and pregnant women often have low blood levels of magnesium. Therefore, it has been suggested that raising magnesium levels may decrease leg cramps during pregnancy. Magnesium taken by mouth has been reported to reduce pregnancy-related leg cramps. Additional research is needed in this area.
Migraine headache (Grade: C)
Migraine headaches can be extremely painful and are often accompanied by nausea. More women suffer from migraine headaches than men. Furthermore, migraine headaches in women can be related to the menstrual cycle. Magnesium has been evaluated for use in migraines. Human studies have found that magnesium sulfate may reduce the intensity of migraine headaches. Low magnesium levels may increase menstrual-related migraines in susceptible women. Additional research is needed to confirm these results.
Mitral valve prolapse (valvular heart disease) (Grade: C)
Mitral valve prolapse (MVP) syndrome is a common disorder characterized by a variety of complaints that affect quality of life. Low magnesium levels and an excess of the catecholamine adrenaline have been suggested as contributing factors in causing MVP. Many patients with heavily symptomatic mitral valve prolapse have low magnesium levels in the blood. Magnesium supplementation has been reported to improve most mitral valve prolapse. Additional research is needed to reach a conclusion.
Muscle spasms (Grade: C)
Magnesium may help prevent involuntary muscle twitching caused by the drug succinylcholine (a neuromuscular blocker). Involuntary muscle twitching is an adverse effect of patients undergoing general anesthesia. Additional high-quality research is needed to confirm these results.
Myocardial infarction prevention (heart attack prevention) (Grade: C)
Magnesium has been used in the treatment of heart attack. Therefore, oral magnesium therapy has been considered a preventive therapy in patients who have survived acute heart attacks. A human study did not show benefit of oral magnesium therapy for prevention in these individuals. The study also suggested that the risk of heart problems might have been increased by this therapy. Additional research is needed in this area.
Pregnancy nutritional supplement (Grade: C)
Many women have low magnesium levels in the body. Magnesium supplementation has been given during pregnancy as a nutritional supplement. Currently, there is not enough evidence to support magnesium supplementation during pregnancy as a means to improve the health of the mother or infant. Additional research is needed in this area.
Pregnancy-related complications (Grade: C)
Magnesium supplementation has been given during pregnancy in order to reduce pregnancy complications. Currently, there is not enough evidence to support magnesium supplementation during pregnancy to reduce pregnancy-related complications. Additional research is needed in this area.
Premenstrual syndrome (PMS) (Grade: C)
Premenstrual syndrome encompasses many physical, psychological, and emotional symptoms related to the menstrual cycle. Symptoms usually appear two weeks before the onset of the menstrual cycle and in some cases significantly affect a woman's daily routine during that time. Oral magnesium has been reported to benefit mood changes associated with premenstrual syndrome (PMS). Additional research is needed in this area.
Shivering (postoperative) (Grade: C)
There is a lack of evidence for the use of magnesium for postoperative shivering. Additional research is needed in this area.
Traumatic brain injury (Grade: C)
There is not enough evidence to support the use of magnesium salts in patients with acute traumatic brain injuries. Magnesium has also been studied for brain hemorrhage in combination with other agents; however, the results are unclear.
Athletic performance (Grade: D)
Magnesium is involved in many reactions in the body. Low magnesium levels may affect exercise performance. Some experts suspect that magnesium levels may not be adequate in many people, especially athletes. Many female athletes do not get enough magnesium from the diet, and magnesium is also lost in the urine with exercise. To date, there is not enough evidence that taking magnesium can improve athletic performance. However, it may reduce the stress response to exercise.
Pre-term labor contractions (Grade: D)
Magnesium has been used for tocolysis (prevention of preterm labor contractions). Available studies have not demonstrated that magnesium is effective for this use. Additionally, it is possible that the use of magnesium for contractions may cause the death of the fetus.