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

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Magnesium chloride is a type of salt used as a nutritional supplement. Magnesium chloride may improve health by increasing the amount of magnesium in people with low levels of it.

Other substances used to increase magnesium levels include magnesium aspartate, magnesium citrate, magnesium gluconate, magnesium glycinate, magnesium lactate, magnesium malate, magnesium oxide, and magnesium sulfate.

Magnesium chloride supplements are commonly found in tablet and capsule forms. Magnesium chloride flakes can also be used for therapeutic baths and foot soaks.

What Is Magnesium Chloride Used For?

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

Benefits of magnesium oxide

Verywell / Brianna Gilmartin

Magnesium Deficiency

Magnesium is an important nutrient. It is responsible for more than 300 processes in the body, including regulation of blood sugar and blood pressure, as well as muscle and nerve function. It also helps with the production of proteins, bone mineral, and DNA, the genetic material in cells.

Although low levels of magnesium, otherwise known as magnesium deficiency, may not have obvious symptoms, some people may experience exhaustion, weakness, depression, fasciculations (involuntary twitches), and arrhythmia (irregular heartbeat).

Long-term magnesium deficiencies can lead to a variety of health concerns, including asthma, migraine, type 2 diabetes, metabolic syndrome, hypertension, atherosclerosis, osteoporosis, and colon cancer

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.

There are certain substances and/or situations that can lead to magnesium deficiency. These include:

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

Type 2 Diabetes

Studies suggest that magnesium supplements increase insulin sensitivity and improve glucose control in those with type 2 diabetes. These results have led some experts to suggest that magnesium can help those with diabetes manage their blood sugar.

However, another study concluded that the magnesium supplement only improved insulin resistance in people with type 2 diabetes who also had magnesium deficiency. It is unknown how deficient in magnesium someone needs to be in order to benefit from taking supplements.

High Blood Pressure

Some evidence suggests that magnesium supplements can help lower high blood pressure, which is also known as hypertension.

According to research, 368 milligrams of magnesium per day over a period of three months reduced the systolic (upper) blood pressure by 2 mmHg and the diastolic (lower) blood pressure by 1.78 mmHg. This effect continued to improve month by month.

Despite these findings, it is not clear if blood pressure continues to get better over time. It is also unknown if these supplements would benefit everyone, as the study focused on those with certain health conditions.

Recap

While some evidence suggests magnesium supplements may help lower high blood pressure in some individuals, more research is needed.

Athletic Performance

Athletes may use magnesium supplements in the hopes that it will boost energy levels and athletic performance. Though some people believe it helped them, studies have had mixed results.

Research has noted that athletes given a one- or four-week dose of magnesium experienced an increase in bench press performance on the day immediately following taking it.

This means that for some individuals a small dose right before athletic activity may have a positive impact on performance. For those who already get enough magnesium in their diet, taking these supplements prior to exercise didn't really improve their performance.

Recap

Magnesium likely does contribute to athletic performance in some individuals, however more research is needed to fully understand how and why magnesium impacts athletic performance.

What Are the Side Effects of Magnesium Chloride?

Magnesium chloride supplements are considered safe if used as directed. Common side effects include stomach upset, nausea, diarrhea, and vomiting. Many of these side effects can be avoided by taking the supplement with food.

Nearly all forms of magnesium supplements can lead to an increase in bowel movements. 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 compared to magnesium glycinate, which requires a smaller dose.

Rare side effects include dizziness, fainting, confusion, allergic reactions, and blood in stool. Call your healthcare provider or seek emergency care if any of these symptoms develop after taking a magnesium supplement.

Interactions

Magnesium can interfere with certain medications. This can impact how well your body is able to process them. Possible interactions include:

  • Aminoglycoside antibiotics, like Gentak (gentamicin) and streptomycin
  • Bisphosphonates, 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)

On the other hand, potassium-sparing diuretics like Aldactone (spironolactone) can increase the amount of magnesium in the blood and lead to side effects.

Separating the doses by two to four hours is often all that is needed to avoid medication interactions.

To avoid medication interactions with your magnesium supplement, be sure to speak with your healthcare provider about any drugs you are taking. This includes prescription, over-the-counter, nutritional, herbal, or recreational medications.

Dosage and Preparation

Magnesium chloride supplements are available as tablets, capsules, and powders with doses ranging from 200 milligrams (mg) to 500 mg. They are used to 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:

  • Magnesium supplements can be taken 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 can be stored safely at room temperature.
  • Discard any supplement that is past its expiration date or shows signs of damage.

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

Is Magnesium Chloride Toxic?

Magnesium toxicity is rare, but high doses are more likely to cause nausea, vomiting, and dizziness. If you are taking a magnesium supplement greater than 350 mg per day, be sure to speak with your medical care provider.

What to Look For With Supplements

Dietary supplements are not carefully monitored in the United States. Because of this, the quality can vary from one brand to the next.

For the highest level of quality, look for supplements that have been independently tested by a certifying body like the U.S. Pharmacopeia (USP), NSF International, or ConsumerLab. The certification confirms that the supplement contains the ingredients and amounts listed on the product label.

Always read the label to check for any added ingredients you may be allergic or sensitive to, including gluten and animal-based gelatin.

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

Common Questions

Is magnesium chloride the best supplement choice?

Magnesium chloride can be dissolved in water, making it easier for your body to absorb and use. Magnesium chloride is absorbed almost completely in the gut. This 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.

What are the best dietary 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

Summary

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

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 helps 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.

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