Should I take a magnesium supplement? Here’s what the science says

Dr. Trisha Pasricha. PHOTO:

Q: I’ve heard that magnesium might be related to fatigue and mood symptoms. Should I start taking supplements?

A: The data on taking a magnesium supplement is underwhelming for some of the purported benefits popularized on social media, including taking magnesium for fatigue and mood symptoms. There are few clear circumstances where magnesium supplementation is warranted, but it’s hard for a doctor like me to give magnesium supplementation an unconditional stamp of approval.

Here is an alternative I can gladly endorse: Eat more magnesium-rich foods. That way, you’ll get the boost of magnesium as well as the other natural benefits of these foods.

What does magnesium do for the body?

Magnesium is an essential ion contained in every cell in our body. We rely on magnesium for many important cellular functions including metabolism, transportation across the cell membranes, and binding hormones.

Can I take a daily magnesium supplement if I’m healthy?

It becomes tricky when relatively healthy people start taking magnesium supplements. Although too much magnesium can be toxic to your body, taking low levels – less than 350 mg daily – probably won’t cause any harm unless you have kidney disease. But it may not do any good either.

It’s important to discuss starting magnesium supplementation with your physician. People with kidney disease may have a harder time getting rid of excess magnesium taken as supplements. Signs of a magnesium overdose include hypotension, poor reflexes, and changes to your heart rhythm.

What are magnesium supplements good for?

Here are some areas where we know magnesium supplementation can be beneficial and some areas where there might be a benefit, but the evidence isn’t as strong:

Mild constipation: A well-known side effect of these supplements is diarrhea, and so I confidently recommend certain magnesium formulations for my patients with mild constipation.

Preeclampsia and other serious conditions in the hospital: When magnesium is given intravenously to patients with preeclampsia, it more than halves the risk of developing eclampsia. However, in these scenarios, the magnesium would be administered by your health-care team in the hospital. Similarly, there are certain critical cardiac arrhythmias, like torsades de pointes, where intravenous magnesium might be given by your health-care team.

Migraines: The randomized trials on oral magnesium supplements here are mixed but trend positive, although the data overall are fairly limited. If you still want to give magnesium a try, increasing the amount of magnesium-rich foods in your daily diet is still likely a better route here.

Mood disorders: A 2016 study found that people with mild to moderate depression who took magnesium supplements for six weeks reported improved mood compared to those who didn’t. However, this study was not blinded, nor placebo controlled, and we don’t have high-quality trials showing a benefit of magnesium for symptoms of anxiety. My advice? Discuss your symptoms with a provider, as psychotherapy and medication are still the options with the strongest evidence to help.

High blood sugar: Increased consumption of magnesium-rich foods is associated with a lower risk of type II diabetes, however, according to the American Diabetes Association, there’s insufficient evidence that magnesium supplements help lower blood sugar in people with diabetes.

High blood pressure: Multiple studies have confirmed that magnesium supplementation will lower blood pressure, but the effect size isn’t profound (on average, a 2.2 mmHg reduction in diastolic blood pressure). It’s worthwhile discussing more effective strategies to lower blood pressure with your physician, keeping in mind that increased dietary magnesium is associated with a lower risk of cardiovascular disease.

Other areas where there’s even less evidence for magnesium supplements is insomnia, leg cramps and dementia.

What foods are highest in magnesium?

Data from the National Health and Nutrition Examination Survey found that about half of Americans don’t meet the estimated dietary requirements for magnesium. Adult males should aim for 400-420 mg daily and females should aim for 310-320 mg daily.

Magnesium is often found in high-fiber foods like leafy greens, seeds and nuts. Try saving those fall pumpkins and roasting the seeds – one cup contains 168 mg of magnesium. These foods tend to have loads of well-established health benefits – they’re abundant in the Mediterranean diet – that would outweigh taking magnesium pills. Here’s a list of common foods that are high in magnesium.

*Leafy greens like spinach and kale

*Seeds and nuts

*Dark chocolate


*Fatty fish


*Whole grains

What are the signs that my magnesium is low?

Critically low levels of magnesium in the blood are associated with serious complications such as abnormal heart rhythms and sudden cardiac death. But poor dietary magnesium intake doesn’t necessarily translate to dire blood levels. Our kidneys do a fantastic job at scavenging and saving the minerals we need and excreting those we don’t.

A few examples of conditions or medications that we know are linked to a magnesium deficiency – and for whom supplementation could indeed be recommend – are:

*Celiac disease

*Crohn’s disease

*Chronic alcohol use

*Insulin resistance or type II diabetes

*Certain diuretic medications, including furosemide and hydrochlorothiazide

*Proton pump inhibitors, like pantoprazole, if taken long-term

What I want my patients to know

I get it: Who wouldn’t rather take a pill than change the way they eat? That’s why I recommend starting with small changes that don’t rob you of your enjoyment of food. Mix in some spinach into your next pasta dish, or reach for a serving of almonds or cashews when you need a snack.



Please enter your comment!
Please enter your name here