What Is Magnesium Chloride?

Supplement form of magnesium may improve blood pressure and diabetes

Bowl of spinach, pumpkin seeds, almonds, magnesium tablets, magnesium capsules, and magnesium powder

Verywell / Anastasiia Tretiak

Magnesium is a mineral that's necessary for many bodily functions, including muscle and nerve function, regulating blood sugar and blood pressure levels, and making protein, bones, and DNA. Magnesium is naturally present in many foods, including whole grains, leafy vegetables, nuts and legumes, fortified foods, and dairy.

Magnesium chloride is one of several types of magnesium supplements. Others include magnesium aspartate, magnesium citrate, magnesium gluconate, magnesium glycinate, magnesium lactate, magnesium malate, magnesium oxide, and magnesium sulfate.

This article explains magnesium chloride's uses, benefits, side effects, dosages, and precautions.

Dietary supplements are not regulated in the United States, meaning the FDA does not approve them for safety and effectiveness before products are marketed. When possible, choose a supplement that has been tested by a trusted third party, such as USP, ConsumerLabs, or NSF.

However, even if supplements are third-party tested, that doesn’t mean that they are necessarily safe for all or effective in general. Therefore, it is important to talk to your healthcare provider about any supplements you plan to take and check in about any potential interactions with other supplements or medications.

Supplement Facts

  • Active ingredient(s): Magnesium chloride and calcium
  • Alternate name(s): Magnesium, magnesium dichloride
  • Legal status: Available over the counter (OTC)
  • Suggested dose: Adults 310 mg to 420 milligrams (mg)
  • Safety considerations: Do not take if allergic to ingredients. Keep out of reach of children. Call Poison Control in case of overdose.

Uses of Magnesium Chloride

Supplement use should be individualized and vetted by a healthcare professional, such as a registered dietitian, pharmacist, or doctor. No supplement is intended to treat, cure, or prevent disease. 

People mainly use magnesium chloride to boost their dietary intake of magnesium. While it doesn't treat conditions by itself, it can help those with low magnesium levels improve certain bodily functions.

In addition, magnesium chloride supplements have well-documented uses in type 2 diabetes, high blood pressure, osteoporosis, and migraines. 

Benefits of magnesium oxide

Verywell / Brianna Gilmartin

Type 2 Diabetes

Researchers have noted a strong correlation between type 2 diabetes and magnesium deficiency. They estimate that 14% to 48% of people with type 2 diabetes are deficient in magnesium.

In a 2015 double-blind, placebo-controlled, randomized trial published in Diabetes and Metabolism, researchers evaluated whether magnesium supplements improved glucose (blood sugar) levels in 116 participants with prediabetes and low magnesium blood levels.

The experimental group received 382 mg of magnesium daily for four months, while the control group received a daily placebo. At the end of the study, 50.8% in the magnesium group improved their glucose levels compared to 7% in the placebo group.

Another study conducted in 2017 and published in Nutrition looked at how magnesium supplementation impacted insulin resistance in people with low magnesium levels. Of the 12 articles included in the systematic review, researchers found the following:

  • Eight clinical trials showed that magnesium supplementation impacted serum fasting glucose concentrations.
  • Five trials found an impact on fasting insulin levels.
  • Seven studies showed reduced insulin resistance.

Even so, the American Diabetes Association does not recommend routine magnesium supplementation for everyone with diabetes, especially those who do not have a magnesium deficiency.

High Blood Pressure

Magnesium helps regulate blood pressure. Therefore, some people with hypertension (high blood pressure) take magnesium supplements to reduce their blood pressure. While some research supports that theory, the effect is usually small.

A 2016 meta-analysis of 34 randomized, double-blind, placebo-controlled trials involving 2,028 participants evaluated the effects of magnesium supplementation on blood pressure. Compared to placebo groups, those who received 368 mg of magnesium per day over three months reduced the systolic (upper) blood pressure by 2 mmHg and the diastolic (lower) blood pressure by 1.78 mmHg.

In addition, a 2012 meta-analysis of 22 trials and 1,173 participants looked at the impact of magnesium supplements on blood pressure. Researchers found that three to 24 weeks of magnesium supplementation with a mean dose of 410 mg decreased systolic blood pressure by 3–4 mmHg and diastolic blood pressure by 2–3 mmHg.

Despite these findings, the evidence is not conclusive, and further research is needed.

Osteoporosis

Since magnesium is involved in the formation of bones, it makes sense that people would turn to magnesium for bone health. In addition, there is evidence that magnesium deficiency may be a risk factor for osteoporosis (low bone density).

About 60% of magnesium in the body is stored in the bones.

However, studies have found that both low and high concentrations of magnesium may have a negative impact on bones. Therefore, researchers believe that maintaining a correct balance is key to bone health.

So, while magnesium is essential for overall bone health, more research is needed before supplementation can be recommended to prevent or treat osteoporosis.

Migraines

Nerves and blood vessels play a role in headaches. Therefore, some research has focused on the relationship between migraines and magnesium.

In a 2015 randomized, double-blind, placebo-controlled, multicenter trial, researchers evaluated magnesium, vitamin B12, and Q10 as a migraine treatment. The study randomized 130 participants who experienced three or more migraines a month into a control or placebo group. For three months, the control group received a daily supplement containing 400 mg vitamin B12, 600 mg magnesium, and 150 mg coenzyme Q10.

After three months, the control group reduced their migraine frequency from 6.2 days per month to 4.4 days, compared to the placebo group, which reduced theirs from 6.2 to 5.2 days. In addition, migraine intensity was decreased in the control group by 4.8 points, whereas the placebo group's was reduced by 2 points. However, since this study involved a combination of ingredients, it's difficult to say how much magnesium played a role.

However, in an evidence-based guideline update by the American Academy of Neurology and the American Headache Society, researchers analyzed 15 non-traditional headache therapies. They concluded that magnesium was probably an effective therapy for preventing migraines.

Other

In addition to the potential health benefits listed above, some people use magnesium to support:

  • Sleep
  • Mood
  • Energy

Magnesium Deficiency

Magnesium deficiency is uncommon in otherwise healthy people. That's because the kidneys limit how much of it your body excretes in urine. However, some situations can lead to magnesium deficiency, including:

How Do I Know If I Have a Magnesium Deficiency?

A magnesium deficiency may need to be correctly identified and diagnosed by a healthcare provider through specific lab tests. Although magnesium deficiency may not have obvious symptoms, some people may experience:

  • Appetite loss
  • Nausea
  • Exhaustion
  • Weakness
  • Depression
  • Fasciculations (involuntary twitches)
  • Arrhythmia (irregular heartbeat)

Some people may develop a magnesium deficiency when intakes are lower over time than recommended levels, they have a specific risk factor for lower than normal levels, or there is a particular reason they are unable to absorb magnesium.

Though magnesium deficiency is uncommon in the United States, research suggests that half of all Americans consume less than the recommended amount of magnesium from food each day.

Long-term magnesium deficiencies can lead to a variety of health concerns, including:

  • Type 2 diabetes
  • Hypertension
  • Hypomagnesemia (lower than usual magnesium in the blood)
  • Osteoporosis
  • Migraine headaches

Magnesium chloride supplements may help improve the health of those with magnesium deficiency.

What Are the Side Effects of Magnesium Chloride?

Your healthcare provider may recommend you take magnesium to prevent or help treat a health condition. However, consuming a supplement like magnesium may have potential side effects. These side effects may be common or severe.

Common Side Effects

Magnesium chloride supplements are considered safe if used as directed. However, typical side effects may include:

  • Stomach upset
  • Nausea
  • Diarrhea
  • Vomiting

You can avoid many of these side effects by taking the supplement with food.

Nearly all forms of magnesium supplements can lead to an increase in bowel movements. However, smaller doses that are more easily absorbed in the intestines tend to cause less stomach upset.

For example, magnesium oxide is more likely to cause diarrhea because it requires a larger dose than magnesium glycinate, requiring a smaller amount.

Severe Side Effects

Severe side effects are rare. They occur most often when you take too much of the supplement or have an allergy to it. They include:

  • Thirst
  • Hypotension (low blood pressure)
  • Dizziness
  • Fainting
  • Confusion
  • Trouble breathing
  • Allergic reactions

Call a healthcare provider or seek emergency care if any of these symptoms develop after taking a magnesium supplement.

Precautions

Magnesium can interfere with certain medications. This interaction can impact how well your body can process them or increase the amount of magnesium in the blood and lead to side effects. Possible interactions include:

  • Aminoglycoside antibiotics, like Gentak (gentamicin) and streptomycin
  • Bisphosphonates (bone-strengthening medication) like Fosamax (alendronate)
  • Calcium channel blockers, like nifedipine and verapamil
  • Quinoline antibiotics, like Cipro (ciprofloxacin) and Levaquin (levofloxacin)
  • Tetracycline antibiotics, like doxycycline and Minocin (minocycline)
  • Thyroid medications, like Synthroid (levothyroxine)
  • Muscle relaxants
  • Diuretics (water pills)

Separating the doses may help you avoid medication interactions.

It is essential to carefully read the ingredient list and nutrition facts panel to know which ingredients are included and in what amounts. In addition, please review the supplement label with your healthcare provider to discuss any potential interactions with foods, other supplements, and medications.

Dosage: How Much Magnesium Should I Take?

Always speak with a healthcare provider before taking a supplement to ensure that the supplement and dosage are appropriate for your individual needs. 

Magnesium chloride supplements are available as tablets, capsules, and powders, with doses ranging from 200 mg to 500 mg. They can help meet your recommended dietary allowance (RDA) of magnesium.

Recommended Dietary Allowance (RDA) of Magnesium
Age Male Female Pregnant Lactating
Birth to 6 months 30 mg 30 mg    
7 to 12 months 75 mg 75 mg    
1 to 3 years 80 mg 80 mg    
4 to 8 years 130 mg 130 mg    
9 to 13 years 240 mg 240 mg    
14 to 18 years 410 mg 360 mg 400 mg 360 mg
19 and older 400 mg 310 mg 350 mg 310 mg

Helpful tips to keep in mind when taking a magnesium supplement:

  • You can take magnesium supplements with or without food.
  • If loose stools occur, try taking a lower dose.
  • Extended-release tablets should be swallowed whole—do not chew, split, or crush the tablet.

Magnesium supplements are meant to boost your dietary intake, not replace a healthy diet.

What Happens If I Take Too Much Magnesium?

Magnesium toxicity is rare, but high doses may cause side effects including:

  • Nausea
  • Vomiting
  • Dizziness

Remember, the amount of magnesium you take in supplement form adds to the amount you get from food. So, be sure that your magnesium supplements don't exceed the recommended upper intake level of 350 mg per day.

If you are taking a magnesium supplement greater than 350 mg per day, speak with a healthcare provider.

How To Store Magnesium

Store magnesium in a cool, dry place. Keep magnesium away from direct sunlight. Discard any supplement that is past its expiration date or shows signs of damage.

Bowl of spinach, pumpkin seeds, almonds, magnesium tablets, magnesium capsules, and magnesium powder
Verywell / Anastasia Tretiak

Similar Supplements

In addition to magnesium chloride, magnesium supplements come in other forms, including:

  • Magnesium oxide
  • Magnesium sulfate
  • Magnesium citrate
  • Magnesium aspartate
  • Magnesium lactate

The body absorbs some forms of magnesium more readily than others. For example, researchers have found that aspartate, citrate, lactate, and chloride forms absorb better.

Frequently Asked Questions

  • Are there benefits to soaking in a bath with magnesium salts?

    Since the skin acts as a barrier, it’s unlikely that much magnesium in a bath gets absorbed through the skin. It's best not to rely on it to replace dietary magnesium.

    However, soaking in magnesium chloride baths may improve skin hydration and reduce inflammation. Some people say that Epsom salt (magnesium sulfate) baths help with sore muscles, but there isn’t strong research to prove how effective it is.

  • Can magnesium supplements get rid of back pain?

    Studies show that magnesium may help reduce various types of pain including headaches and back pain. Try eating more magnesium-rich foods and talk to your healthcare provider about taking magnesium supplements to manage pain. 

  • Can magnesium help me fall asleep?

    If you have low levels of magnesium, increasing your magnesium intake could help with sleeping problems. Several studies show that taking magnesium supplements may help older adults with insomnia fall asleep more easily and have better-quality sleep.

  • Does magnesium chloride lower blood sugar?

    It may. Magnesium may improve insulin sensitivity. If you have type 2 diabetes, this means it can help your body to use the insulin it makes more efficiently, reducing insulin resistance and helping to lower blood sugar.

    However, in people with type 1 diabetes, magnesium supplements can change the way your body uses the insulin you take, which may cause low blood sugar.

Sources of Magnesium and What To Look For

The best source of magnesium is food because the body absorbs it better. However, when you don't get enough magnesium in your diet, you can also get additional magnesium with supplements.

Food Sources of Magnesium

In general, nuts, seeds, whole grains, dark leafy greens, dried beans, and low-fat dairy products are the best sources of magnesium. Foods with magnesium include:

  • Pumpkin seeds (1 ounce): 168 mg
  • Almonds (1 ounce): 80 mg
  • Spinach (1/2 cup): 78 mg
  • Soy milk (1 cup): 61 mg
  • Edamame (1/2 cup): 50 mg
  • Dark chocolate (1 ounce): 50 mg
  • Peanut butter (2 tablespoons): 49 mg
  • Avocado (1 cup): 44 mg
  • Baked potato (1 medium): 44 mg
  • Brown rice (1/2 cup): 42 mg
  • Plain yogurt (8 ounces): 42 mg
  • Banana (1 large): 32 mg
  • Salmon (3 ounces): 26 mg
  • Low-fat milk (1/2 cup): 24 mg
  • Whole wheat bread (1 slice): 23 mg
  • Chicken breast (3 ounces): 22 mg

Magnesium Supplements

Magnesium chloride can be dissolved in water, making it easier for your body to absorb and use. In addition, magnesium chloride is absorbed almost entirely in the gut. This absorption makes it more readily available in your bloodstream.

Organic salts like magnesium chloride are slightly more effective than inorganic salts because they tend to be easier for the body to absorb, especially if multiple low doses are taken.

Summary

Magnesium chloride is a mineral supplement used to increase your intake of magnesium. Those with low magnesium levels may experience uncomfortable symptoms that a magnesium supplement may help reverse or improve. Be sure to speak with your healthcare provider if you are taking any other medications before you begin a magnesium supplement.

19 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. National Institutes of Health. Office of Dietary Supplements. Magnesium: Fact sheet for consumers.

  2. Gommers LMM, Hoenderop JGJ, Bindels RJM, de Baaij JHF. Hypomagnesemia in type 2 diabetes: a vicious circle? Diabetes. 2016;65(1):3-13. doi:10.2337/db15-1028

  3. Guerrero-Romero F, Simental-Mendía LE, Hernández-Ronquillo G, Rodriguez-Morán M. Oral magnesium supplementation improves glycaemic status in subjects with prediabetes and hypomagnesaemia: A double-blind placebo-controlled randomized trial. Diabetes & Metabolism. 2015;41(3):202-207. doi:10.1016/j.diabet.2015.03.010

  4. Morais JBS, Severo JS, de Alencar GRR, et al. Effect of magnesium supplementation on insulin resistance in humans: a systematic review. Nutrition. 2017 Jun;38:54-60. doi:10.1016/j.nut.2017.01.009

  5. Evert AB, Boucher JL, Cypress M, et al. Nutrition therapy recommendations for the management of adults with diabetes. Diabetes Care. 2013;36(11):3821-3842. doi:10.2337/dc13-2042

  6. Zhang X, Li Y, Del Gobbo LC, et al. Effects of magnesium supplementation on blood pressure: a meta-analysis of randomized double-blind placebo-controlled trials. Hypertension. 2016;68:324-33. doi:10.1161/HYPERTENSIONAHA.116.07664

  7. Kass L, Weekes J, Carpenter L. Effect of magnesium supplementation on blood pressure: a meta-analysis. Eur J Clin Nutr. 2012;66(4):411-418. doi:10.1038/ejcn.2012.4

  8. Gröber U, Schmidt J, Kisters K. Magnesium in prevention and therapyNutrients. 2015 Sep 23;7(9):8199-226. doi:10.3390/nu7095388

  9. Castiglioni S, Cazzaniga A, Albisetti W, Maier J. Magnesium and osteoporosis: current state of knowledge and future research directions. Nutrients. 2013;5(8):3022-3033. doi:10.3390/nu5083022

  10. Gaul C, Diener HC, Danesch U, et al. Improvement of migraine symptoms with a proprietary supplement containing riboflavin, magnesium and Q10: a randomized, placebo-controlled, double-blind, multicenter trial. J Headache Pain 2015;16:32. doi:10.1186/s10194-015-0516-6

  11. Holland S, Silberstein SD, Freitag F, Dodick DW, Argoff C, Ashman E. 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. 2012;78(17):1346-1353. doi:10.1212/WNL.0b013e3182535d0c

  12. National Library of Medicine. Magnesium deficiency.

  13. National Institutes of Health: Office of Dietary Supplements. Magnesium fact sheet for health professionals.

  14. Rosanoff A, Weaver CM, Rude RK. Suboptimal magnesium status in the United States: are the health consequences underestimated? Nutrition Reviews. 2012;70(3):153-164. doi:10.1111/j.1753-4887.2011.00465.x

  15. Gröber U, Werner T, Vormann J, Kisters K. Myth or reality—transdermal magnesium? Nutrients. 2017;9(8):813. doi:10.3390%2Fnu9080813

  16. Tarleton EK, Kennedy AG, Rose GL, Littenberg B. Relationship between magnesium intake and chronic pain in U. S. adults. Nutrients. 2020;12(7):2104. doi:10.3390%2Fnu12072104

  17. Mah J, Pitre T. Oral magnesium supplementation for insomnia in older adults: a systematic review & meta-analysis. BMC Complement Med Ther. 2021;21(1):125. doi: 10.1186/s12906-021-03297-z

  18. Cleveland Clinic. Magnesium rich food.

  19. Schuchardt JP, Hahn A. Intestinal absorption and factors influencing bioavailability of magnesium-an update. Curr Nutr Food Sci. 2017;13(4):260-278. doi:10.2174/1573401313666170427162740

By James Myhre & Dennis Sifris, MD
Dennis Sifris, MD, is an HIV specialist and Medical Director of LifeSense Disease Management. James Myhre is an American journalist and HIV educator.