Share on Facebook

6 Things to Know Before You Take a Magnesium Supplement

Magnesium may help you have stronger bones as well as better sleep, pain relief, and heart health, so some people take this mineral as a supplement. However, here's what you need to know before you take magnesium.

A vital mineral

Magnesium is an important mineral when it comes to your health, says Carolyn Dean, MD, ND, author of “The Magnesium Miracle” and a medical advisory board member of the Nutritional Magnesium Association. Magnesium may help lower your risk of heart disease, type 2 diabetes, and osteoporosis while also helping to reduce anxiety, insomnia, blood pressure, and migraine headaches. It may even help you age more gracefully, according to research published by the National Institutes of Health (NIH). You can get enough magnesium by eating a variety of foods (more on that later). However, some people may not get enough magnesium from their diet, and men over age 7o and teens girls may be at greater risk of a deficiency than other people, according to the Office of Dietary Supplements at the NIH. However, before you pop a supplement, there are a few things you need to know first.

White and multi-colored supplementsAfrica Studio/Shutterstock

How much magnesium do you need?

Magnesium already naturally exists in our bones, muscles, and cells. The earth’s crust and seawater also contain the mineral. We need between 310 and 420 milligrams of magnesium a day for optimal functioning and to maintain our body’s reserves, according to the NIH. Not sure if you’re getting enough? These 10 signs will let you know if you have a magnesium deficiency.

Receiving vitamins. Concept illness, colds, cure, fall and winterOlha Tsiplyar/Shutterstock

Why take a magnesium supplement?

“Magnesium is one of the key electrolytes your body needs, affecting nearly every system in your body,” Dr. Dean says. “It activates enzymes that control digestion, absorption, and the utilization of proteins, fats, and carbohydrates.” We can get some or all of your daily allotment from foods including green leafy vegetables (like spinach), whole grains, beans, and nuts, but many people choose to take supplements to make sure they are getting enough of this essential mineral, she says. (Breakfast cereals and other foods may be fortified with the mineral, so make sure to read food labels.)

In addition, some groups of people are more likely to be magnesium deficient so if you have a gastrointestinal disease, diabetes, alcohol dependence, or are over age 65 then you may need to supplement with extra magnesium, according to the NIH.

Woman with stomach pain talking to a doctorDragon Images/Shutterstock

What type of magnesium supplement should you take?

Not all types of magnesium supplements are created equal because some forms of magnesium are more easily absorbed and used by the body, Dr. Dean explains. Magnesium supplements come in aspartate, citrate, lactate, chloride, oxide, sulfate, threonate, malate, and glycinate forms but some are more bioavailable—meaning they are easier for your body to use, according to the NIH. Confused? The ones that are best absorbed are those that can be dissolved in water, including all the forms except the oxide and sulfate forms, the NIH notes.

The newer supplements, including magnesium glycinate, threonate, and malate, while more expensive, were found to be better absorbed and cause less stomach discomfort, according to a study published in the Journal of The American College of Nutrition. Dr. Dean prefers magnesium citrate powder, as it is affordable, easy to find, and dissolves quickly in water, making it easy to take.

Other magnesium supplements may double as laxatives or antacids. The skin can absorb epsom salts, another form of magnesium, during a bath. (Spoiler alert: Don’t expect miracles from an Epsom salt bath.)

woman sleeping in a white bedStock Asso/Shutterstock

How should you take a magnesium supplement?

For best results, take the supplement with food, as that will help it absorb better and will minimize stomach discomfort, says Stephanie Schiff, RDN, a registered dietitian at Northwell Health’s Huntington Hospital in Huntington, New York. Timing can also be important. “Some studies recommend that magnesium supplements be taken at night, as they help relax the muscles in the body and can help you fall asleep,” she adds. (Can’t sleep? Get a sleep doctor’s and nutritionist’s advice on how to eat to sleep better.)

Woman clutching her stomach with bathroom in backgroundEmily frost/Shutterstock

Can you overdose on magnesium supplements?

Magnesium supplements in reasonable doses are safe for most people, according to the NIH. Overdosing is rare but the most common side effect from too much magnesium is diarrhea and stomach pain, however, taking over 5,000 mg a day can lead to magnesium toxicity, which can be fatal without treatment, they note. People with kidney or heart problems should exercise caution, according to the National Magnesium Association. There may be some other vitamin mistakes you don’t realize you’re making as well.

doctor with patient, writing on a clipboardwutzkohphoto/Shutterstock

Can you take other supplements or medications with magnesium?

Be careful loading up on supplements as taking magnesium can interfere with absorption of other minerals, says Tod Cooperman, MD, a supplement expert and president of Consumer Labs, a supplement testing site. “So if you take a multivitamin, calcium, or zinc, take magnesium at a different time of day,” Dr. Cooperman warns. “Magnesium may also reduce the absorption of medications such as blood thinners, anti-diabetes drugs, diuretics, and drugs used to treat osteoporosis. Check with your doctor first if you are on any medications.”

Medically reviewed by Samantha Cassetty, MS, RD, on February 13, 2020

Denise Mann, MS
Denise Mann is a freelance health writer whose articles regularly appear in WebMD, HealthDay, and other consumer health portals. She has received numerous awards, including the Arthritis Foundation's Northeast Region Prize for Online Journalism; the Excellence in Women's Health Research Journalism Award; the Journalistic Achievement Award from the American Society for Aesthetic Plastic Surgery; National Newsmaker of the Year by the Community Anti-Drug Coalitions of America; the Gold Award for Best Service Journalism from the Magazine Association of the Southeast; a Bronze Award from The American Society of Healthcare Publication Editors (for a cover story she wrote in Plastic Surgery Practice magazine); and an honorable mention in the International Osteoporosis Foundation Journalism Awards. She was part of the writing team awarded a 2008 Sigma Delta Chi award for her part in a WebMD series on autism. Her first foray into health reporting was with the Medical Tribune News Service, where her articles appeared regularly in such newspapers as the Detroit Free Press, Chicago Sun-Times, Dallas Morning News, and Los Angeles Daily News. Mann received a graduate degree from the Medill School of Journalism at Northwestern University in Evanston, Ill., and her undergraduate degree from Lehigh University in Bethlehem, Pa. She lives in New York with her husband David; sons Teddy and Evan; and their miniature schnauzer, Perri Winkle Blu.