Magnesium Supplements: A Complete Guide

Katelyn Hagerty FNP

Medically reviewed by Kristin Hall, FNP

Written by Our Editorial Team

Last updated 12/03/2020

Magnesium is an essential macromineral that plays a role in hundreds of important processes within your body.

As one of the most abundant minerals in your body, magnesium is responsible for maintaining your cardiovascular health, ensuring your bones remain dense and strong, helping to produce testosterone and other hormones and even regulating certain aspects of your mood.

Despite its importance, research shows that many people don’t get enough magnesium. In fact, scientific study data suggests that between 10 percent and 30 percent of the population has subclinical magnesium deficiency.

Being deficient in magnesium can cause a variety of negative health effects, from poor sleep to an increased risk of issues such as heart disease and osteoporosis.

Luckily, treating a magnesium deficiency isn’t complicated. You can increase your magnesium levels by eating foods rich in magnesium, or by using a magnesium supplement.

Below, we’ve explained what magnesium is and how it works in your body as a mineral. We’ve also talked about how much magnesium you need for optimal health and wellbeing, as well as how magnesium supplements can fit into your health routine. 

What Is Magnesium?

Magnesium is a type of mineral. It’s one of the most abundant minerals in the body. Your body uses magnesium in more than 300 enzyme systems, including those related to essential tasks such as energy production and protein synthesis. 

Your body even uses magnesium in order to create DNA and RNA. Put simply, magnesium is an essential mineral that plays a role in a vast range of biological functions, from the mundane to those critical for your health and survival.

Magnesium is found in both plant and animal-based foods. Many everyday foods, particularly those that contain fiber, provide magnesium. Your body absorbs about 30 to 40 percent of the magnesium you eat, making your diet an important source of magnesium.

Since diets can vary hugely from person to person, many people don’t get enough magnesium from foods and beverages. 

A lot of common foods, including processed foods and refined flours and sugars, are devoid of magnesium. If your diet is heavy on processed foods and low on fibrous foods, healthy meats, vegetables and other magnesium-rich foods, you may be at risk of magnesium deficiency.

If you’re deficient in magnesium, making certain changes to your diet and taking a magnesium supplement may be helpful. We’ve talked about this more further down the page.

Benefits of Magnesium

Magnesium offers a large, diverse range of benefits, particularly for people who are deficient in magnesium. Benefits of magnesium include:

  • Improved physical performance. Research shows that magnesium may boost strength and physical performance. For example, one study found that magnesium may be linked to increased strength, while another noted better exercise performance in elderly women.

  • Increased testosterone production. Research shows that magnesium is closely linked to testosterone. One study even found that men who used magnesium supplements had a larger increase in testosterone than their peers.

  • Better sleep. Magnesium deficiency is often associated with insomnia. Several studies have found that magnesium and related supplements may have positive effects on sleep quality.

  • Better mental health. Research shows that magnesium deficiency is associated with a range of mental health issues, including depression. There’s also some evidence that magnesium supplementation may help to treat mild-to-moderate depression.

  • Improved heart health. Magnesium plays a key role in cardiovascular health. Research has found that magnesium deficiency is linked to a higher risk of heart health issues and that magnesium consumption is inversely linked with some heart-related problems.

Magnesium also has a large range of other health benefits, including reducing inflammation and potentially preventing diseases such as osteoporosis. It’s also linked to lower blood pressure and prevention of issues such as migraines.

We’ve gone into more detail on these benefits and the scientific research behind them in our full guide to the benefits of magnesium

Virtual Primary Care

Connect with qualified healthcare providers online

How Much Magnesium Do You Need?

The amount of magnesium you need each day can vary depending on your sex, age and other factors. 

According to the Institute of Medicine of the National Academies, the Dietary Reference Intakes (DRIs) for magnesium are as follows:

  • For men aged 14 to 18, 410mg per day

  • For men aged 19 to 30, 400mg per day

  • For men aged 30 to 51+, 420mg per day

  • For women aged 14 to 18, 360mg per day (if pregnant, 400mg per day)

  • For women aged 19 to 30, 310mg per day (if pregnant, 350mg per day)

  • For women aged 31 to 50+, 320mg per day (if pregnant, 360mg per day)

Magnesium Supplements: Types, Pros & Cons

Magnesium supplements are available over the counter and can be a convenient option if you’re deficient in magnesium. Most magnesium supplements are sold as capsules or tablets, although magnesium is also available as a topical oil.

You can also often find magnesium as an ingredient in multivitamin supplements and other daily supplements that contain essential minerals. 

The biggest advantages of using a magnesium supplement is that it makes it significantly easier to reach the Dietary Reference Intake for magnesium. By using a supplement, you can increase your magnesium intake without having to make any changes to your diet. 

With this said, magnesium supplements do have some disadvantages. The first is that they can cause side effects when taken to excess, including nausea and diarrhea. We’ve discussed these more further down the page. 

The second is that magnesium supplements can interact with certain medications. We’ve also covered this further down the page. If you use prescription medications, it’s important to talk to your healthcare provider before using a magnesium supplement. 

Types of Magnesium Supplements

Several different types of magnesium preparations are available. You can typically find the type of magnesium used in supplements in the ingredients list. It’s very important to check the exact type of magnesium you’re buying, as some forms are much better absorbed than others. 

Generally, scientific research shows that magnesium citrate, aspartate, chloride and lactate are most effectively absorbed by the body. Magnesium glycinate, or chelated magnesium, may be less likely to cause diarrhea than other forms of magnesium.

We’ve listed the most common forms of magnesium below, along with information on each type and its bioavailability (the amount that’s successfully absorbed by your body).

Magnesium Oxide

Magnesium oxide is a common form of magnesium that’s used in health supplements and as a treatment for heartburn. It’s also often used as a short-term laxative before medical procedures such as surgery. 

You can find magnesium oxide as an ingredient in many over-the-counter supplements, such as magnesium capsules and tablets. 

Although magnesium oxide has a high magnesium content per weight, some research suggests that it’s poorly absorbed by the body compared to other common forms of magnesium. One study even found that it produced no difference in magnesium levels compared to a placebo.

Magnesium Citrate

Magnesium citrate is another common form of magnesium. It’s available as a health supplement and is occasionally used as a laxative for treating constipation on a short-term basis.

Research indicates that magnesium citrate is generally well absorbed by the body, with a higher level of bioavailability than magnesium oxide. A study from 2003 found that after 60 days of use, magnesium citrate was one of the most effective forms of magnesium in terms of bioavailability.

Magnesium Gluconate

Magnesium gluconate is typically used to treat low levels of magnesium, which may develop as a result of gastrointestinal disorders, vomiting and/or diarrhea, kidney diseases and other health issues.

Magnesium Chloride

Another common form of magnesium, magnesium chloride is available in supplements. It has a high degree of solubility and is absorbed well by the body. Magnesium chloride is often sold as flakes, which are added to warm bath water for relaxation and muscle recovery.

Magnesium Hydroxide

Magnesium hydroxide is a common form of magnesium used in health supplements. Like other forms of magnesium, it’s also used as a short-term treatment for constipation. 

Magnesium Glycinate

Magnesium glycinate, often referred to as chelated magnesium, is another form of magnesium used in health supplements. It’s a highly available form of magnesium that’s absorbed in a part of the small intestine close to the stomach.

Since it’s absorbed in a different part of the small intestine than other magnesium supplements, magnesium glycinate might be less likely to cause diarrhea than other forms of magnesium. It may also be an option for people with intestinal health conditions, or intestinal resection.

Magnesium Aspartate

Another common form of magnesium, magnesium aspartate can be found in many magnesium supplements. It has a high degree of bioavailability, meaning your body can generally absorb it successfully.

Magnesium Complex Supplements

Some magnesium supplements are called “magnesium complex” supplements. These typically contain several forms of magnesium in one capsule or tablet. You can find the specific forms of magnesium used in these supplements by checking the ingredients label. 

Side Effects of Magnesium Supplements

When consumed through food, excessive amounts of magnesium usually aren’t harmful. This is because your kidneys are able to filter out excess magnesium and eliminate it from your body in your urine.

However, using magnesium supplements excessively may cause certain side effects and safety issues. One common side effect is diarrhea, which may be accompanied by nausea and cramps that affect the abdominals.

Diarrhea may be more common with supplements that contain magnesium carbonate, chloride, gluconate, and oxide. If you experience side effects after taking a magnesium supplement, it’s important to talk to your healthcare provider.

Magnesium Toxicity

Taken as recommended at a normal dosage, magnesium supplements are safe for most people to use. However, very large doses of magnesium can lead to hypermagnesemia, or magnesium toxicity.

Magnesium toxicity is a particular risk for people affected by chronic kidney disease, people who are undergoing cancer treatment and women being treated for preeclampsia.

Common early symptoms of magnesium toxicity include diarrhea, muscular weakness, vomiting, nausea and low blood pressure. When levels of magnesium are very high, magnesium toxicity may cause severe symptoms, including respiratory paralysis and cardiac arrest.

If you have one of the risk factors listed above, it’s important that you don’t use any magnesium supplements without first talking to your healthcare provider. 

If you experience any of the symptoms of magnesium toxicity, contact your healthcare provider or seek emergency medical care immediately. 

Magnesium Drug Interactions

Magnesium may interact with certain medications, including some antibiotics, bisphosphonates, diuretics and proton pump inhibitors. Some of these interactions can affect absorption, making other medications less effective than normal.

If you’re prescribed any medication, or have any existing health issue for which you’re currently undergoing treatment, make sure to talk to your healthcare provider before using magnesium or other health supplements. 

Other Sources of Magnesium

Magnesium supplements are a convenient way to increase your magnesium intake and reach the Dietary Reference Intake. However, it’s also possible to increase your magnesium level by changing your diet to incorporate more magnesium-rich foods.

Many common foods contain magnesium. Try incorporating the following foods into your diet to increase your magnesium intake naturally:

  • Vegetables. Many vegetables contain magnesium. Green vegetables such as spinach and broccoli are both high in magnesium. Vegetables are also rich in other nutrients, making them good additions to your diet.

  • Nuts. Almonds, cashews and peanuts all contain more than 15 percent of the Dietary Reference Intake for magnesium. Try snacking on nuts instead of processed snacks, which are typically devoid of any substantial magnesium content.

  • Seeds and beans. Many seeds and beans are rich in magnesium. Try eating pumpkin seeds (which contain 37 percent of the Dietary Reference Intake for magnesium in one serving), black beans, kidney beans and chia seeds.

  • Milk and soy milk. Soy milk is high in magnesium, with one cup containing 15 percent of the Dietary Reference Intake. Milk is slightly lower but still a good source of dietary magnesium, with around six percent of the Dietary Reference Intake per cup.

  • Red meat and poultry. Meats such as ground beef, steak and poultry are all excellent sources of magnesium. One three-ounce serving of beef or chicken breast contains five percent of the Dietary Reference Intake for magnesium.

  • Fish. Many different types of fish, including salmon and tuna, contain large amounts of magnesium. One three-ounce serving of salmon contains approximately six percent of the Dietary Reference Intake for magnesium.

Many starchy foods also contain magnesium. You can find magnesium in potatoes, breakfast cereals (particularly fortified breakfast cereals), oatmeal, whole wheat bread, rice (particularly brown rice) and other starchy carbohydrates.

As a general rule, try to prioritize complex carbohydrates over processed ones, as they’re usually higher in magnesium content. For example, half a cup of brown rice contains 10 percent of the daily value for magnesium, whereas half a cup of white rice only contains two percent.

In Conclusion

Magnesium is an essential mineral for optimal health and wellbeing. It plays a role in everything from your cardiovascular health and bone density to your production of important hormones like testosterone.

If you’re deficient in magnesium, consider using a magnesium supplement. However, it’s best to talk to your healthcare provider before using anything, particularly if you use other medication or have a health condition that may affect your magnesium levels. 

Learn More About the Benefits of Magnesium

From your brain to your body, magnesium plays an important role in hundreds of vital biological processes. Our complete guide to the benefits of magnesium goes into more detail about what magnesium does and the advantages of maintaining healthy magnesium levels. 

This article is for informational purposes only and does not constitute medical advice. The information contained herein is not a substitute for and should never be relied upon for professional medical advice. Always talk to your doctor about the risks and benefits of any treatment.

📫 Get updates from hims

Insider tips, early access and more.