Which magnesium supplement is right for me?

If your only experience with over-the-counter magnesium comes from the occasional glug of milk of magnesia to relieve your digestive distress, guess what? There is a whole wide world of magnesium supplements out there! This wonder nutrient is available in several formulations, with each variety aiming to treat different symptoms.

To make it easier for you to head to your local pharmacy, health food store, or vitamin shop and buy the best kind of magnesium supplement for you, we’ve asked experts to lay out all your options—and make some recommendations for how, when, and why to take magnesium.

What is magnesium?

Magnesium is an essential mineral that the human body needs to regulate everything from your muscle and nervous system to your energy production, blood sugar, and blood pressure, according to the National Institutes of Health (NIH). Most adults need between 300 and 400 milligrams (mg) of magnesium per day, much of which comes from what you eat—foods like cooked beans, cashews and almonds, avocados, bananas, green leafy vegetables, dark chocolate, whole grains, and brown rice have a  high magnesium content, as are many fortified foods. You can find a full list of magnesium-rich food sources from the NIH’s Office of Dietary Supplements here.

Still, you may not be getting as much of this nutrient as you think.

“It’s estimated that about 80% of people are deficient in magnesium,” says naturopathic physician Jaquel Patterson, ND, medical director of Fairfield Family Health in Connecticut.

A 2017 Scientifica study confirms this is a reasonable estimate, revealing that about two-thirds of the Western population is likely deficient in magnesium (a condition called hypomagnesemia). Most healthy people can handle a short-term deficiency, but in the long-term you may notice symptoms such as:

• Loss of appetite
• Nausea or vomiting
• Fatigue and muscle weakness
• Muscle cramps
• Heart arrhythmia
• Numbness or tingling

People with certain health conditions, like Crohn’s disease, celiac disease, and Type 2 diabetes are at higher risk of becoming deficient in magnesium, as are people on certain medications (like chemotherapy drugs, some antibiotics, diuretics, and proton pump inhibitors).

Benefits of magnesium

The health benefits of magnesium supplementation can be broad, though in some cases there isn’t enough research to say definitively that increasing your intake is a reliable treatment.  Magnesium may help to improve the following: 

Constipation 

Supplemental magnesium can regulate your bowel movements by acting as an osmotic laxative, drawing water into the intestines and making movements easier to pass. Magnesium citrate and magnesium hydroxide are common examples of osmotic laxatives. 

RELATED: Constipation treatments and medications

Muscle function

If you suffer from restless legs syndrome or muscle cramps, a dietary supplement may be able to help. Unfortunately, much of this advice is anecdotal; several reviews of studies examining the link between magnesium and the relief of muscle cramps, including this one from Cochrane, showed no clear evidence that magnesium supplements are effective (a little bit of research shows they could be useful for pregnant women, but not for the rest of the population.) 

Migraine

Both the American Headache Society and the American Migraine Foundation agree that magnesium supplements may be effective in reducing the severity and frequency of migraine headaches, possibly because people with migraine have been shown to have lower than average levels of magnesium. In recent years, it’s even become a regular part of many migraine sufferers’ preventative care routines, especially for those with menstrual migraines.

RELATED: Migraine treatment and medications

High blood pressure

Magnesium has vasodilator properties. Meaning it can help relax blood vessels and maintain normal blood pressure. The current evidence points to a small reduction in blood pressure with magnesium supplementation, which over time, could lead to better heart health and a lower risk of cardiovascular disease, heart attack, and stroke. For example, a 2016 review of studies in Hypertension found that an average supplementation of 368 mg per day for three months was associated with lower systolic and diastolic blood pressure levels. 

RELATED: How to lower blood pressure naturally

Insulin resistance

According to NIH, magnesium deficiency may increase insulin resistance—often a precursor to developing Type 2 diabetes. A 2007 meta-analysis published in the Journal of Internal Medicine looked at the role of magnesium intake in preventing Type 2 diabetes; almost all the studies considered showed that increasing magnesium intake by even 100 mg a day could increase insulin sensitivity and lower your risk of Type 2 diabetes.

Depression and anxiety

Because magnesium contributes to nerve function, its role in preventing and treating neurological disorders has also been studied. According to a 2018 study in Nutrients, magnesium deficiency may be responsible for higher incidences of depression, anxiety, and chronic pain—and increasing intake may alleviate some of the symptoms associated with these conditions. There has also been some research studying magnesium’s effects on sleep quality and insomnia, as well as its possible benefits for children with attention deficit hyperactivity disorder (ADHD).

Magnesium side effects 

Magnesium is generally considered to be safe. According to Jeffrey Fudin, Pharm.D., managing editor of paindr.com, side effects of magnesium supplementation—like nausea, vomiting, facial flushing, sleepiness and lethargy, decreased blood pressure, and cardiac abnormalities—are usually only seen in very high doses above 5,000 mg per day.

Although you likely won’t take enough magnesium to have side effects, it’s possible that a supplement could interact with another medication you’re taking or be contraindicated for an existing medical condition. These include:

• Drugs used to treat osteoporosis, like Fosamax, which can have reduced absorption from the stomach when taken with magnesium. “These two medications should be separated by at least two hours,” says Dr. Fudin. Otherwise, it could impact bone health.
• Certain classes of antibiotics, including tetracyclines, such as doxycycline, and quinolones, such as levofloxacin and ciprofloxacin. Dr. Fudin recommends taking these antibiotics two hours before or six hours after magnesium to avoid any interaction.
• Certain diuretics used to treat heart disease, like amiloride, spironolactone, and triamterene, which Dr. Fudin says can cause the body to retain magnesium and could cause dangerously high levels if you’re also supplementing with it.

Finally, people with risk factors like diminished kidney function—including older adults and people with diabetes—are more likely to accumulate dangerously high levels of magnesium, says Dr. Fudin, so they should only supplement with magnesium under the care and supervision of a physician or pharmacist.

Types of magnesium  

If you’re Googling “magnesium supplement” and seeing a dozen different varieties pop up, it might feel like you need a chemistry degree to tell the difference between each one.

Thankfully, we can make this easier for you: It’s all about relationships. Depending on what other elements the magnesium is combined with, some forms absorb more readily into the bloodstream than others—and this can change how the magnesium works in your body.

“Different formulation options are important because they have varying ability to be absorbed from the gut to the bloodstream,” says Dr. Fudin. “Some are more water soluble compared to others and are therefore more readily absorbed into the blood, [while] the salts that are less well absorbed leave magnesium behind in the gut, where it becomes an osmotic laxative.”

Readily absorbed: Magnesium chloride, magnesium citrate, magnesium aspartate, L-threonate, lactate, glycinate, malate, orotate, and taurate

Less well-absorbed: Oxide and sulfate (which is typically applied to skin, but there’s not much evidence to show it’s well-absorbed that way, either)

Best magnesium supplements 

It’s up to you and your healthcare provider to determine which magnesium supplement you should take. But since finding the right formulation is often a matter of weighing how well the magnesium is absorbed into your bloodstream against what you want or need the magnesium to do, you can make a reasonable guess at where to start.

 Note: These are the average dosage recommendations provided by supplement manufacturers; it’s best to follow the professional medical advice of a  healthcare provider regarding magnesium dosage. Always inform your physician of any supplements you begin taking.

Magnesium supplements for kids

You should always talk to your children’s pediatrician before giving them any supplements, but magnesium can, in many cases, be a safe option for kids with ADHD or restless legs syndrome.

“Magnesium L-threonate comes in a kid-friendly powder and may have brain benefits that can help with ADHD,” says Dr. Patterson. “Magnesium oxide or citrate can be used for kids with restless legs syndrome or kids who just need help settling down at night.”

Per the Mayo Clinic, the recommended dietary allowance (RDA) for children up to age 3 is 40 to 80 mg per day, while children between the ages of 4 and 6 can take 120 mg and kids between 7 and 10 can take 170 mg. Your pediatrician, however, may recommend a higher or lower dosage based on your child’s overall health and symptoms.

Dr. Patterson, for example, usually suggests parents of older children start with 300 mg of magnesium and slowly increase the amount if needed. However, dosages of 500 to 600 mg may cause loose stool (which is a sign that you should lower your dose slightly). If your child doesn’t like drinking magnesium supplements, many are available in chewable or even gummy formulations.