your natural self

Do You Need Magnesium? Forms, Absorption, and Benefits

Published on February 20, 2024

By Lisa Stockwell

Lisa Stockwell

Lisa Stockwell has worked as a copywriter, writer, author, and editor for 35 years, specializing in the field of healthcare since 2009. She recognized the need for reliable health information while supporting friends through unique health challenges and refocused her career to bring clarity and compassion to healthcare communications. Lisa is a graduate of the University of California, Berkeley and a lifelong Northern Californian.

Magnesium is the fourth most abundant mineral in the human body and plays a vital role in numerous biological processes. Despite its significance, over half of the people in the United States may have suboptimal magnesium levels.REF#3623

Are you one of them?

Ideally, you should be able to get adequate amounts of magnesium from the food you eat. However, factors like soil depletion, food processing, and modern dietary trends often limit proper intake of these sources. Consequently, magnesium supplementation has become increasingly popular. 

Knowing whether you need a supplement and what kind of supplement to take can be challenging, especially since there is a wide variety of magnesium forms, each with distinct bioavailability and potential effects. This article reviews the functions of magnesium and its different forms and discusses its potential benefits for optimizing various aspects of health and well-being.

What is Magnesium, and Why is it Essential?

Magnesium is a critical mineral that resides within your body in specific proportions and locations. The average human body holds approximately 25 grams of magnesium, of which about 53 percent is found in your bones, about 27 percent in your muscles, and about 19 percent in your non-muscular soft tissue. Your bloodstream contains less than one percent of total magnesium.REF#3624

Magnesium is absorbed into your body through your gut from the food you eat. Excess is excreted from the kidneys. When available in adequate amounts, Magnesium offers a range of health benefits and is essential to your overall health. It is known to support the following functions:REF#3624

  • Muscle support: It helps your muscles contract, relax, and produce energy, whether you're hitting the gym or just climbing the stairs.
  • Bone strength: Magnesium teams up with calcium to build strong, healthy bones, reducing your risk of fractures and keeping your skeleton sturdy.
  • Energy production: It plays a key role in converting food into usable energy, ensuring you have the fuel to power through your day.
  • Brain function: Magnesium helps your nerves send signals efficiently, contributing to normal neurological function as well as sleep.REF#3625
  • Heart health: By helping to regulate blood pressure, magnesium may help maintan heart rhythm and vascular tone.REF#3626
  • Blood sugar balance: Magnesium may contribute to healthy blood sugar levels, supporting overall metabolic health.REF#3627

Although less than one percent of Magnesium circulates through your bloodstream, the body possesses remarkable adaptability to use Magnesium from reserves in bones, muscles, and potentially soft tissues. Think of it as a reserve tank that helps maintain stable Magnesium concentrations in your body's fluids. This ensures your body can maintain critical functions during short-term fluctuations or mild Magnesium deficiencies.

While our bones store a significant amount of Magnesium, its accessibility becomes a concern with age and illness. Studies have shown that low Magnesium content in aging adults may affect normal inflammatory response.REF#3628 Also, if you are struggling with certain illnesses, such as gastrointestinal disease, diabetes, or alcoholism, you may be at higher risk for Magnesium deficiency.

Additionally, modern agricultural practices deplete soil of essential minerals, leading to food with lower Magnesium content. Food processing also can strip away naturally occurring Magnesium, further reducing dietary intake.

Chronic depletion can potentially overwhelm your body’s ability to support important physiological functions, like muscle contraction and nerve transmission. Therefore, it’s critical to consume adequate amounts of Magnesium through diet or supplementation to support your overall health.

How to Assess Your Magnesium Levels

Since less than one percent of the total Magnesium in your body is in your bloodstream, when you test your blood, the level of Magesium in your blood serum offers limited insights. A blood test can’t reflect the total amount your body stores in your bones, muscles, and soft tissue. 

Even if you have normal serum levels, you might have Magnesium deficiency, where those hidden stores in your muscles and bones are dwindling. 

So, what else can you do to assess your Magnesium status? Here are some tips:

  • Listen to your body: Muscle cramps, fatigue, anxiety, and sleep troubles can be red flags for magnesium deficiency. 
  • Track your intake: Are you fueling your body with Magnesium-rich foods like leafy greens, nuts, and seeds? Keeping a food diary can help determine if you’re consuming enough Magnesium.
  • Consult your healthcare provider: Your healthcare provider can assess your risk factors, symptoms, and test results to paint a clearer picture of your Magnesium status.

Remember, optimal magnesium levels are key to vibrant health. While the serum test offers a starting point, consider it just one piece of the puzzle. As with every aspect of health maintenance, knowing your own body and keeping tuned into how you feel is critical for long-term wellness. 

Consume Natural Sources of Magnesium

The best way to optimize your Magnesium intake is to eat the right foods. Make sure you add the following Magnesium-rich foods to a balanced daily diet to enjoy all the critical nutrients you need. 

  • Leafy greens: Leafy green vegetables are like nature’s mini Magnesium powerhouses, boasting impressive Magnesium content. Kale, spinach, dandelion greens, and Swiss chard offer 20 to 24 mg per cup of chopped raw greens. 
  • Nuts and seeds: This excellent source of magnesium can be eaten as a snack between meals or added to salads, breads, or baked goods. Add nuts and seeds to fish, chicken, or meat dishes to provide a satisfying crunch alongside their valuable mineral content. Pumpkin seeds pack a serious punch with 167 mg per ounce. Almonds, cashews, and sunflower seeds offer from 82 to 92 mg per ounce. Peanuts, walnuts, and pecans contain 34 to 47 mg per ounce. 
  • Legumes: Black beans, kidney beans, white beans, chickpeas, and lentils provide 78 to 120 mg per cooked cup, making them an affordable and protein-rich way to boost your magnesium intake. 
  • Whole grains: Brown rice, quinoa, and oats can contribute 78 to 118 mg of Magnesium per cooked cup, providing sustained energy and valuable nutrients alongside their fiber content. 
  • Soy products: A half cup of firm tofu provides over 70 mg of Magnesium, while a cup of soy milk gives you over 36 mg. 
  • Beets: Beets are a nutrient-rich root that offer over 31 mg per cup.
  • Fish: Different fish offer different levels of Magnesium. A 3-ounce serving of cooked mackerel offers over 62 mg of Magnesium while the same portion of salmon offers around 26 mg. 
  • Dark chocolate: If you want a great way to indulge your sweet tooth, dark chocolate (70% cocoa or higher) offers a magnesium content of over 64 mg per ounce. However, remember moderation is key, as dark chocolate also contains sugar and fat. 

Many other foods contain Magnesium, including yogurt, poultry, and beef. To make sure you’re consuming enough Magnesium, use an online nutrition calculator to determine values of the foods in your daily diet. Note that processing methods can deplete Magnesium content. So when planning a healthy diet, select raw or minimally processed options whenever possible to maximize your dietary Magnesium intake.

Types of Magnesium: Benefits and Bioavailability of Common Supplements

If you are considering a Magnesium supplement, selecting the right one can be confusing. There are at least 11 forms available, and some supplements combine more than one form. 

Studies have shown that bioavailability is not related to the volume of the mineral in the supplement. The bioavailability of Magnesium depends on its chemical form and its ability to dissolve in your digestive system. While a higher dose might contain more overall Magnesium, a poorly absorbed form won't deliver its full potential benefits.

The most common types you’ll find in supplement form include:

Magnesium Glycinate (MgGly)

This gentlest form features Magnesium bound to the amino acid glycine, resulting in superior absorption and minimal gastrointestinal (GI) side effects.REF#3629 MgGly readily crosses the intestinal barrier and avoids the laxative effect often associated with other forms. 

It’s believed to have calming properties, which may make it suitable for individuals sleep disturbances or stress-related concerns.REF#3630 However, more research is needed to confirm these effects. MgGly is often priced higher than other forms.

Magnesium Oxide (MgO)

While known for its high traces of elemental Magnesium and affordability, MgO has been shown to have poorer solubility and therefore lower bioavailability than other forms. This often translates to potential laxative effects.REF#3631 While readily available and cost-effective, MgO may help support healthy digestion but might not be suitable for individuals who want to avoid the laxative effects or those seeking to raise their Magnesium levels.

Magnesium Citrate (MgC)

Studies have shown this form of Magnesium, which contains citric acid, to have higher bioavailability than MgO.REF#3632 MgC (in powder form) is noted for its ability to dissolve quickly in water. This translates to efficient uptake into the bloodstream, making it a popular choice for individuals aiming for quick Magnesium replenishment.

Magnesium Malate (MgMal)

Bound to malic acid, MgMal exhibits moderate bioavailability and potential benefits for energy production. Malic acid, a key component of the Krebs cycle, plays a crucial role in energy production at the cellular level. 

The theory is that by supplying both Magnesium and malic acid, this form might enhance energy metabolism. Studies suggest it might be less laxative than MgC, making it attractive for individuals seeking energy support without significant digestive concerns. However, further research is needed to confirm its specific advantages over other forms.

Magnesium L-Threonate (MgT)

This relatively new Magnesium compound features Magnesium bound to L-threonine, an amino acid. Preliminary research suggests enhanced bioavailability and potential benefits for cognitive function.REF#3633 Studies indicate MgT might be an intriguing option for individuals concerned about cognitive health or age-related cognitive decline. However, extensive research is still needed to fully understand its long-term efficacy and potential side effects.

Magnesium Sulfate

Also known as Epsom salts, Magnesium sulfate is a crystalline mineral compound composed of Magnesium, sulfur, and oxygen. It's readily soluble in water and has been used for centuries for various purposes. While it can be absorbed through the skin during a bath, the amount absorbed is minimal and unlikely to contribute to your daily Magnesium intake significantly. Therefore, it's not considered a reliable source of dietary Magnesium.

Choosing the right Magnesium form requires a personalized approach considering individual needs, absorption concerns, and desired outcomes. Due to individual variances in the way Magnesium is absorbed and utilized, it’s best to consult with your healthcare provider or dietician to determine the best option for your body. 

Dosages and Side Effects of Magnesium

According to guidelines developed by the Food and Nutrition Board at the Institute of Medicine (IOM) at the National Academies, 350 mg a day of Magnesium is considered a tolerable upper limit. It’s unlikely that you will exceed a tolerable limit through eating food. Your kidneys will eliminate excess amounts through urine.

While the Recommended Daily Allowance is set higher for men aged 19 to 51 (400 to 420 mg/day versus 320 for women), when using supplements, start with a lower dose (around 200mg/day) and gradually increase that dose to minimize potential side effects.

Common side effects of excess Magnesium supplementation include diarrhea, nausea, and stomach cramps. 

Since individual needs vary, your healthcare professional can recommend the appropriate dosage and form of Magnesium based on your unique circumstances. They can also advise on potential interactions with medications you may take and monitor for any adverse effects.


  • 1. , "Micronutrient Inadequacies in the US Population: an Overview", Linus Pauling Institute.
  • 2. , "Magnesium basics", Clinical Kidney Journal.
  • 3. , "The effect of magnesium supplementation on primary insomnia in elderly: A double-blind placebo-controlled clinical trial", Journal of Research in Medical Sciences.
  • 4. , "Dietary Magnesium and Cardiovascular Disease: A Review with Emphasis in Epidemiological Studies", Nutrients.
  • 5. , "Effect of magnesium supplementation on insulin resistance in humans: A systematic review", Nutrition.
  • 6. , "Magnesium in Aging, Health and Diseases", Nutrients.
  • 7. , "Study of magnesium bioavailability from ten organic and inorganic Mg salts in Mg-depleted rats using a stable isotope approach", Magnesium Research.
  • 8. , "The Effects of Magnesium Supplementation on Subjective Anxiety and Stress—A Systematic Review", Nutrients.
  • 9. , "A Randomized Double-blind Placebo-controlled Trial on the Effect of Magnesium Oxide", Journal of Neurogastroenterology and Motility.
  • 10. , "Effects of Magnesium Citrate, Magnesium Oxide, and Magnesium Sulfate Supplementation on Arterial Stiffness: A Randomized, Double‐Blind, Placebo‐Controlled Intervention Trial", Journal of the American Heart Association.
  • 11. , "A Magtein®, Magnesium L-Threonate, -Based Formula Improves Brain Cognitive Functions in Healthy Chinese Adults", Nutrients.