The Health Benefits of Magnesium

This supplement may help with neuromuscular relaxation

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Magnesium is a mineral that's essential for overall physical health. Approximately half of the magnesium in our bodies is found in our bones. The rest serves to help in cellular functioning throughout the body’s various systems. Magnesium plays an important role in muscle function, heart rhythm, blood pressure, immune system functioning, and blood sugar level.

Health Benefits

Neuromuscular Excitability

Magnesium is often used in different types of cases related to overexcitation of the neuromuscular system.

This overexcitation of the neuromuscular system is common in people who use stimulant medications, and can show up as muscle twitches, as well as jaw clenching and teeth gnashing. A review of several case studies indicates promise for oral magnesium to alleviate these latter symptoms, otherwise known as bruxism.

Restless leg syndrome is a condition in which people experience an urge to move their legs. Taking oral magnesium supplements was found to improve symptoms of restless leg syndrome in a study of 100 patients with type 2 diabetes.

Women who received an intravenous magnesium salt had a 52% lower risk of subsequent convulsions than those given diazepam, in one 2011 review of 1687 women experiencing seizures after pregnancy.

Irritable Bowel Syndrome

Studies published in 2016 and 2017 showed that consumption of mineral water rich in magnesium sulfate can improve the frequency of bowel movements in people who have irritable bowel syndrome with constipation (IBS-C), but the effect has not been shown to last for longer than six weeks.

This temporary laxative effect of magnesium appears to come through two different mechanisms:

  • Muscle relaxation: Magnesium may relax the muscles in the intestines, which can help to establish a smoother flow as the stool passes through the bowels.
  • Stool softener: Magnesium draws water into the intestines, working as an osmotic laxative. This increase in water stimulates bowel motility. It also softens and increases the size of the stool, triggering a bowel movement and helping to make stools easier to pass.

Possible Side Effects

Side Effects of Magnesium
Verywell / Cindy Chung

Magnesium's most common side effect is diarrhea, which can cause:

  • Dehydration
  • Nutritional deficits
  • Weight loss
  • Electrolyte imbalance with serious potential effects on your heart, muscles, and breathing


Toxic amounts of magnesium can cause problems with the kidneys and may produce severe adverse events affecting the intestines. A condition called ischemic colitis, which can cause permanent damage to the intestines, has been described as a result of magnesium toxicity. Read the product labels carefully to prevent excessive magnesium intake.

Medication Interactions

Supplemental magnesium may interfere with the effectiveness of some prescription medications. Before starting magnesium, tell your healthcare provider and pharmacist if you are taking any of the following:

  • Laxatives
  • Vitamin supplements
  • Diuretics
  • Chemotherapy drugs
  • Osteoporosis medications
  • Thyroid medications
  • Certain antibiotics, such as ciprofloxacin and moxifloxacin
  • Antacids

In some cases, you can minimize a drug interaction by separating magnesium from the co-prescribed drug by four to six hours. In others, your healthcare provider may need to either substitute or adjust the dose of the co-prescribed drug.


Your kidneys are directly responsible for clearing magnesium from the blood, so you should not take vitamin and mineral supplements (unless prescribed by your healthcare provider) if you have kidney disease or if you need dialysis, as even normal amounts may produce toxicity.

If you are using magnesium to treat your constipation from IBS-C, you should be aware that the dose of magnesium used to treat constipation is not intended to be used as a dietary supplement.

If your kidneys are impaired, the excessive intake of magnesium can lead to an abnormal accumulation referred to as hypermagnesemia. This, in turn, can lead to heart rhythm problems, respiratory distress, and even cardiac arrest.

Dosage and Preparation

The National Institutes of Health (NIH) has published a fact sheet outlining the recommended daily intake of magnesium. The amount recommended varies by age, and different guidelines are offered for women who are pregnant or breastfeeding. This is the total amount, which includes magnesium intake from foods, too.

You can take magnesium as a vitamin pill, in a prepared liquid form, or as a powder mixed into a liquid. Magnesium supplements come in a variety of forms, each paired with a different chemical. These magnesium salt combinations are absorbed at different rates by the small intestine. As a result, each supplement differs in the speed at which it can meet the need for magnesium and therefore has a different dose threshold necessary for the effects to be felt.

This makes it challenging to know whether a lower dose used in a clinical study of one salt formulation will be effective for someone attempting to replicate the effects with a different formulation. If the dose used in both studies is sufficient to meet the need for magnesium, the effects will likely be comparable. Keep this in mind when interpreting this research and consult with your healthcare provider before starting any treatment regimens.

What to Look For

Checking the Supplement Facts label on the back of the magnesium packaging will allow you to check the active dose per serving as well as any other ingredients that may be included, such as flavorings, fillers, or binders.

Third-party testing organization ConsumerLab investigated 40 popular magnesium supplements on the market and found several that disintegrated quickly when exposed to moisture, several that contained harmful amounts of lead, and several that were improperly labeled based on the contents. It can be good to check up on a specific manufacturer through one of these third-party testing sites in order to be sure you can trust what you see on the label.

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5 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Nissani M. A bibliographical survey of bruxism with special emphasis on non-traditional treatment modalities. J Oral Sci. 2001;43(2):73-83. doi:10.2334/josnusd.43.73

  2. Metta V, Sampathb N, VM R, Iska A. Primary restless legs syndrome in patients with type 2 diabetes mellitus: efficacy of magnesium & co enzyme q10 therapy. Journal of the Neurological Sciences. 2015;357(1):e271. doi:10.1016/j.jns.2015.08.952

  3. Garrison SR, Allan GM, Sekhon RK, Musini VM, Khan KM. Magnesium for skeletal muscle cramps. Cochrane Database of Systematic Reviews. 2011;(11):CD009402. doi:10.1002/14651858.CD009402

  4. Bothe G, Coh A, Auinger A. Efficacy and safety of a natural mineral water rich in magnesium and sulphate for bowel function: A double-blind, randomized, placebo-controlled study. Eur J Nutr. 2017. 56(2):491-499. doi:10.1007/s00394-015-1094-8

  5. Naumann J, Sadaghiani C, Alt F, Huber R. Effects of sulfate-rich mineral water on functional constipation: A double-blind, randomized, placebo-controlled study. Forsch Komplementmed. 2016;23(6):356-363. doi:10.1159/000449436

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