What to know about magnesium supplements

by Kaiser Permanente |
Young person reading supplement bottle label

Have you heard the buzz about magnesium supplements? From helping with sleep, easing anxiety, and minimizing migraines, people claim taking magnesium supplements offers a wide range of benefits. Does this mineral deserve the spotlight? 

What is magnesium?

Magnesium is found in every cell in your body. It’s a necessary nutrient for hundreds of bodily functions.1  

Along with potassium and calcium, it keeps your muscles, including your heart, contracting and relaxing. It helps regulate the messages your nervous system sends. Paired with vitamin D, it supports your bones and teeth. It’s also necessary to convert food into energy. And if you’re sick, it helps your body fight the infection.

About 99% of the magnesium in your body is in your bones, muscles, and soft tissues.2 If the levels circulating in your blood get low, your body can pull it from there. This means a magnesium blood test can show normal levels when the magnesium in your body is low.3

What happens if I have low magnesium?

If you’re deficient in magnesium, you’ll have noticeable symptoms such as loss of appetite, nausea, and vomiting. If you have low levels, you’ll have no symptoms. But long-term low levels of magnesium might increase your risk for certain conditions. These include high blood pressure, heart disease, type 2 diabetes, migraine headaches, and osteoporosis.4

Low magnesium levels have also been found in people experiencing depression, difficulty sleeping, and anxiety.5 Some studies have found that taking magnesium supplements reduced these symptoms.6 

Most adults should get from 310 to 420 milligrams of magnesium daily. Yet, according to the National Institutes of Health, 48% of Americans aren’t getting enough.7

Foods high in magnesium

You can find magnesium in many foods. One of the best ways to increase your magnesium intake is by choosing foods that are rich in magnesium. Some good sources include:8

  • Nuts and seeds like cashews, Brazil nuts, and pumpkin seeds. These 3 have over 70 mg per 1 ounce serving.
  • Legumes like cooked black beans, black-eyed peas, or chickpeas. These supply over 80 mg of magnesium per cup. Peanuts are another good source. A 1 ounce serving of roasted peanuts gives you almost 50 mg of magnesium.
  • Grains such as brown rice, kasha, and oatmeal. One cup of any of these 3 cooked grains provides between almost 60 to over 80 mg of magnesium.
  • Fruits like avocados, bananas, and jackfruit. Each cup provides over 40 mg of magnesium.
  • Greens are great for your plate — and a few are also rich in magnesium. A cup of cooked spinach provides you with 196 mg of magnesium. Beet greens will give you 110 mg. And 1 cup of collards will give you 50 mg. 
  • Surprising sources include water, certain breakfast cereals, and chocolate. Hard or fortified water can have up to 120 mg magnesium per liter. A few fortified breakfast cereals can have over 50 mg per serving. And a small piece of dark chocolate can have over 12 mg.

In addition to magnesium, plant-based foods like whole grains, beans and lentils, and fruits and vegetables provide necessary fiber and essential antioxidants. 

3 types of magnesium supplements

It’s best to get nutrients like magnesium from a healthy diet. But that can sometimes be difficult. Another option is to add a supplement to your routine. 

Here are 3 common magnesium supplements to consider.

Magnesium citrate

This is magnesium bound with citric acid, which gives citrus foods their tartness. Magnesium citrate is one of the most popular magnesium supplements. Your digestive system easily absorbs this form of magnesium, so it’s a good choice to raise low magnesium levels. It’s also used, at high doses, to treat constipation. 

Magnesium glycinate

Magnesium glycinate is a combination of magnesium and the amino acid glycine. Some studies have shown glycine can enhance sleep.9 This form is also easily absorbed and can have less of a laxative effect than other forms. 

Magnesium chloride

Magnesium chloride is sold as a supplement and often added to lotions sold to treat sore muscles. As a supplement it’s easily absorbed and is a good choice to raise low magnesium levels. It’s also used to treat constipation at high doses. 

If you’re considering a magnesium supplement, you shouldn’t take more than 350 mg a day. It’s best to start with 100 mg a day to see how you feel. 

Some supplements can also interfere with certain medications. So, talk to your doctor before starting a new supplement. 

You can find more healthy lifestyle tips on our Health and Wellness site.  

1Magnesium in Diet, MedlinePlus, National Library of Medicine, accessed February 16, 2024.

2Magnesium, Fact Sheet for Health Professionals, National Institutes of Health, Office of Dietary Supplements, accessed February 7, 2024. 

3Magnesium Blood Test. MedlinePlus, National Library of Medicine, accessed February 7, 2024. 

4See note 2.

5Gisele Pickering et al., “Magnesium Status and Stress: The Vicious Circle Concept Revisited,” Nutrients, November 28, 2020. 

6Andrea Botturi et al., “The Role and the Effect of Magnesium in Mental Disorders: A Systematic Review,” Nutrients, June 3, 2020. 

7See note 2.

8FoodData Central, U.S. Department of Agriculture, Agricultural Research Service, accessed February 7, 2024. 

9MA Razak, et al., “Multifarious Beneficial Effect of Nonessential Amino Acid, Glycine: A Review,” Oxidative Medicine and Cellular Longevity, March 1, 2017.