Published on February 21, 2022

Magnesium supplements come in many different compounds, forms, and types… here are some key items to consider when choosing a magnesium supplement for your health

Key Points

  • The amount of magnesium absorbed from a supplement can depend on many things, including the current magnesium levels in the body, an individual’s age, the magnesium supplement used and dose of magnesium taken, how it is taken, medications, and other factors
  • While the magnesium ion itself can be absorbed into all cells and tissues of the body, the preparation of magnesium and the compound used in a supplement can affect the amount of magnesium absorbed in the digestive system and its bioavailability within different tissues (such as the muscles, heart and brain), with some compounds having dose-dependent effect
  • Always look at the amount of elemental magnesium provided with each serving size for the supplements being considered; for example, a supplement containing 1,000 mg of its magnesium compound may only contain 50 mg of magnesium itself – be sure to check the nutrition label to see!

Magnesium is essential to all cells and plays an important role as a co-factor for more than 80% of known metabolic functions, with up to 1,000 enzymes relying on magnesium to help regulate those functions. Yet nearly half of all individuals 1 year and older and more than two thirds of teenagers (ages 14-18) and elderly adults (ages 71 and over) in the United States do not get enough of this vital nutrient.

Magnesium deficiency may present as asymptomatic, or may lead to symptoms such as muscle cramps, anxiety, depression, tremors, irregular heartbeat, and others. There are several causes of magnesium deficiency, including gastrointestinal disorders, the use of certain medications, excessive sweating, high intake of caffeine and alcohol, prolonged stress, depleted soils, and processed food diets which lack magnesium.

Supplementation is Necessary to Correct Magnesium Deficiency: How do you choose the right magnesium supplement for you?

Magnesium is needed in its positively charged ionic state for a wide array of physiological and biochemical processes in the body. In magnesium supplements, the magnesium ion is combined with another compound. Magnesium is absorbed in its combined state for certain compounds (through dipeptide channels) or it is broken down during digestion and absorbed in its ionic form (through ion channels).

The amount of magnesium absorbed can also depend on current magnesium levels, an individual’s age, the dose of magnesium taken, how it is taken, and medications, among other factors.

A systematic review of 14 animal and human studies by Pardo et al. looked at several of these factors to compare the bioavailability of different magnesium supplements and concluded that, while all magnesium supplements likely have the potential to maintain physiological levels of magnesium in the body and correct deficiency, the absorption and distribution of magnesium are dependent on the dose, form, and preparation administered. Not all supplements are equal.

A Break-down of Magnesium Supplements

Here are some factors to consider when choosing between different magnesium supplements.

Magnesium Compound

This is the combination of the magnesium ion bound to another molecule (such as citrate or carbonate) to make a stable magnesium compound. While the magnesium ion itself is highly absorbed and able to reach all cells and tissues of the body, the compound used can affect its absorption in the digestive system and the bioavailability of the magnesium (percentage of magnesium available) to different tissues (such as the muscles, heart and brain), with some compounds having dose-dependent effect. For example, when Ates et al. (2019) measured magnesium in the brain between just a few different magnesium compounds, magnesium taurate accumulated more in a non-dose-dependent, while magnesium glycinate and magnesium citrate accumulated only at the highest doses. Keep in mind that this study was done in mice, therefore tissue specific findings may differ in humans.

Some of the molecules magnesium is bound to may have their own beneficial health effects as well. For example, taurine is known to benefit the heart while malic acid (from magnesium malate) may be beneficial for fibromyalgia. It is important to keep in mind, however, that if supplementing to treat a magnesium deficiency, the most important consideration is the absorption, bioavailability, and the amount of the magnesium itself in the compound (see more below).

There are two main groups of magnesium compounds. Inorganic formulations (including salts, metals, minerals, and other carbon-free compounds) include magnesium chloride and magnesium sulfate, while organic formulations (containing bonds associated with living organisms, such as the form found in plants and animals) include magnesium citrate, magnesium malate, and magnesium carbonate. Inorganic forms of magnesium have been found to be less bioavailable than organic form since organic complexes tend to have higher solubility overall and are less dependent on pH to become ionized. However, these differences don’t come into play for certain formulations, such as supplements containing a more stabilized magnesium ion.

Formulation/Preparation of Magnesium Supplement

There is great variability among magnesium products, even among those containing the same magnesium compound. Some supplements contain a stabilized, ionized form of magnesium, such as several liquid supplements, pharmaceuticals, and mineral water. Magnesium in its ionic state has a higher absorption rate from the gut and is highly successful at getting into the blood and tissues, however, since the magnesium ion is highly reactive, it will bind to another molecule immediately if it is not stabilized.

Preparation Form (Liquid vs Powder vs Solid)

Several studies have found differences in absorption of magnesium based on the supplement preparation, even when comparing the same magnesium compound. For example, one study found that magnesium oxide is better absorbed in effervescent tablets compared to capsule form, while another study found that magnesium aspartate in powder form was better absorbed than in capsule form. Liquid magnesium supplements may be especially beneficial for those with digestive issues and are more likely to contain an ionized form of magnesium.

Dose of Magnesium Taken

Always look at the amount of magnesium provided with each serving size for the supplements being considered! Many people miss this important step when choosing supplements, especially for those requiring multiple tablets, capsules, or units per serving. Here are some simple rules to remember when choosing any supplement:

  • Look at the serving size on the label. Never assume that the amount listed on the product’s front label is what is included in “one” of what’s in the bottle
  • Supplement labels should state the amount of elemental magnesium contained in the supplement; look for this amount (sometimes listed as magnesium FROM the compound in the supplement)
  • Keep in mind that a supplement containing 1,000 mg of its magnesium compound may only contain 50 mg of magnesium itself – be sure to check the nutrition label to see!

Digestive Health and Other Factors May be Important to Consider

Solubility of different forms of magnesium can also be dependent on the pH of the gut and health of the digestive tract. Overall gut health plays a role, as do certain medications (such as bisphosphonates, some antibiotics, and proton pump inhibitors) and diet. In fact, the FDA has declared a black box warning for proton pump inhibitors causing magnesium deficiency. Eating foods high in fermentable fiber favors the absorption of magnesium by reducing pH and increasing solubility. The level of certain hormones, such as parathyroid hormone and calcitriol (the active form of vitamin D), genetics, and gastro-intestinal problems can also affect magnesium absorption. Conditions that cause malabsorption can also impair absorption of magnesium, such as chronic pancreatitis, celiac disease, lactose intolerance, cystic fibrosis and others.

The Dreaded Laxative Effect

The laxative effect is another limiting factor in dosing magnesium. Poor absorption of magnesium supplements drives this effect. For example, some studies have demonstrated that only 4% of magnesium oxide is absorbed from the intestines, with the rest being flushed through the urine or bowels. High doses of magnesium citrate are used as a bowel prep for colonoscopies because of the laxative effect. If someone is very deficient in magnesium, they may want to take more magnesium but are prevented by this laxative effect. In these cases, and when digestive health is an issue, Epsom salt baths or forms of topical magnesium may be beneficial in place of or in addition to an oral magnesium supplement, such as one containing a stabilized magnesium ion that is more likely to be absorbed.

Supplementing to Correct Magnesium Deficiency and Improve Health

Whatever magnesium supplement you choose, one of the best ways to tell if it’s the right one for you is to track your symptoms. With magnesium, some of the first symptoms that have been shown to improve upon supplementation include better sleep, less muscle cramping, stabilization of blood pressure, an increased sense of calm, improved energy and focus, fewer heart palpitations, better joint mobility and less pain. Identify your major one or two symptoms and track them using the myTrackers in your personal GrassrootsHealth account as you start taking your new magnesium supplement!

Measure Your Magnesium Level

Since the standard serum magnesium testing used by most doctors is highly inaccurate at identifying a magnesium deficiency, symptom tracking can be as or even more important than testing to make sure you have chosen the right brand, product, dose, etc. of magnesium. And while the absolute best measurement of magnesium in the body is an Ionized Magnesium Blood Test, it is not widely used and is difficult to access. GrassrootsHealth offers a second-best way to measure magnesium status at home using the whole blood magnesium test. This test measures the amount of magnesium in your blood cells as well as the plasma/serum, which is a better indicator of magnesium status than the serum magnesium test offered by most doctor’s offices and hospitals.

Are You Getting and Absorbing Enough Magnesium and Other Important Nutrients?

Having and maintaining healthy vitamin D levels and other nutrient levels can help improve your health now and for your future. Choose which to measure with vitamin D, such as your omega-3s, and essential minerals including magnesium and zinc, by creating your custom home test kit today. Take steps to improve the status of each of these measurements to benefit your overall health. You can also track your own intakes, symptoms and results to see what works best for YOU.

Enroll and test your levels today, learn what steps to take to improve your status of vitamin D (see below) and other nutrients and blood markers, and take action! By enrolling in the GrassrootsHealth projects, you are not only contributing valuable information to everyone, you are also gaining knowledge about how you could improve your own health through measuring and tracking your nutrient status, and educating yourself on how to improve it.

What Does it Take YOU to Get Your D to 40 ng/ml (100 nmol/L)?

Did you know your health could be greatly affected by making sure you have a vitamin D level of at least 40 ng/ml (100 nmol/L)? Help us help you.

STEP 1 - Do you know what your vitamin D level is? If not, be sure to test today to find out.

STEP 2 – Determine your target level. Are you at your target level? Experts recommend a level of at least 40-60 ng/ml (100-150 nmol/L).

STEP 3 – Need to boost your level? Use the D*calculator to see how much vitamin D it may take to reach your target. Opt for the Loading Dose for a quicker boost.

STEP 4 – Optimize how your body absorbs and utilizes vitamin D with co-nutrients and these simple steps.

STEP 5 – Re-Test! This is an important step to make sure you have reached your target level, and to ensure you are not taking too much! Re-testing after 3-4 months is recommended.

STEP 6 – Adjust, Repeat…

Give your immune system the nutrients it needs to support a healthy you and protect yourself from unnecessary diseases, especially COVID-19.


The first Randomized Controlled Trial on vitamin D and COVID-19 has shown a 96% lower risk of ICU admission for those receiving vitamin D (as 25(OH)D to quickly boost vitamin D blood levels) along with the standard treatment, compared to those receiving standard treatment alone.

These results support many previous observational studies showing a relationship between vitamin D levels and intake and COVID-19 severity.

Review the Latest Nutrient Research for COVID-19

GrassrootsHealth Nutrient Research Institute has launched the new Immune Boost project with the use of our myData-myAnswers nutrient health system that nearly 15,000 people are already using for their health. Specific markers that influence immune health are suggested for testing as part of this project including:

  • Vitamin D
  • Omega-3 Index
  • Essential elements magnesium, selenium, and zinc
  • hsCRP

Our goal is to demonstrate how one can use the Nutrient Research Model established by Dr. Robert Heaney to show the effect of vitamin D serum levels of at least 40 ng/ml (100 nmol/L) on risk reduction for all ethnicities in the population. Status and intake of other nutrients will also be analyzed for any type of relationship to immune status and symptom severity. Join the project today!

Please let us know if you're interested in helping sponsor this project.

CLICK HERE for updates and new information about the project.

Through GrassrootsHealth Nutrient Research Institute, you can also test your essential elements magnesium, copper, zinc and selenium, toxins such as lead, mercury and cadmium, as well as your omega-3 levels, inflammation levels and thyroid stimulating hormone (TSH) level. Find out your levels today! Log on to the test selection page (click the link below) to get your tests and see for yourself if your levels can be improved.

Make sure you track your results before and after, about every 6 months!

Click Here to Access the Test Page

How can I track my nutrient intake and levels over time?

To help you track your supplement use and nutrient levels, GrassrootsHealth has created the Personal Health Nutrient Decision System called

For each specific supplement, you can track what days you take it, how much, and many other details.  This will help you know your true supplemental intake and what patterns of use work for you to reach and maintain optimum nutrient levels. Check it out today!