The Best Absorbed Magnesium

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Our bodies need a wide range of vitamins and minerals to stay healthy, build new tissue, and repair themselves from injuries.

Among the most important of these is magnesium: a crucial mineral for transmitting of nerve signals throughout your body, bone health, and more. Magnesium is particularly tricky for our bodies to absorb unless it is attached to other molecules.

That’s why many top-tier magnesium supplements are advertised as either magnesium citrate or magnesium oxide. Not sure which magnesium supplement you should target for overall wellness? This guide can help.

Below, you’ll find a detailed breakdown of magnesium and why the body has difficulty absorbing this mineral by itself.

We’ll also go over magnesium citrate versus oxide to help you determine which type of magnesium supplement is best for you. Let’s dive in!

Magnesium in a Nutshell

Magnesium is a critical nutrient for bodily health. Although you can find magnesium in a variety of food products (both naturally and through supplementation), many people live with a magnesium deficiency, which can lead to a variety of health problems.

However, magnesium is the fourth most abundant mineral on the earth and the ninth most abundant mineral in the universe.

Magnesium can often be found in saltwater, as the mineral is very water-soluble. You can find magnesium in foods like green vegetables, lean and red meats, and even in spring water.

How Our Bodies Use Magnesium

In a nutshell, magnesium is a cofactor necessary for the completion of over 300 enzyme reactions.

Why does this matter?

Without getting too technical, enzyme reactions are necessary so your body can do things like creating new cells, utilizing energy from your food, and repairing daily wear and tear. At the cellular level, many typical reactions would be impossible without enzymes, which help to lower the energy requirements for those reactions.

In this way, magnesium is crucial so your body can perform a variety of essential tasks. These include:

  • Protein synthesis, which is essential for daily tissue healing and also if you want to build muscle
  • Muscle and nerve functionality
  • Blood glucose control
  • Blood pressure regulation
  • Energy production
  • Glycolysis
  • Oxidative phosphorylation
  • And more

Perhaps most importantly of all, magnesium is necessary, so your body can develop healthy bones, and so it can synthesize DNA and RNA. It’s also crucial for transporting calcium and potassium ions across cell membranes, which is the big reason why magnesium is important for the conduction of nerve signals through individual nerve cells.

An average adult body will have about 25 g of magnesium at any given time.

Between 50% and 60% of that magnesium will be present in the bones, with the rest in soft tissues. Because of this, it can be challenging to determine whether you are suffering from magnesium deficiency, as doctors can only measure magnesium levels through a variety of tests.

However, you can sometimes tell if you are magnesium deficient if:

  • You have difficulty building muscle
  • You experience regular muscle cramps or irregular contractions
  • You have an irregular heartbeat
  • Your body doesn’t absorb all the nutrients necessary from its food
  • And more

As always, speak to your doctor for proper research and consultation.

How Much Magnesium Do We Need?

According to the National Institutes of Health, the recommended daily requirements for magnesium are as follows based on your age and sex:

  • 0-6 month: 30 mg for both males and females
  • 7-12 months: 75 mg for both males and females
  • 1-3 years: 80 mg for both males and females
  • 4-8 years: 130 mg for both males and females
  • 9-13 years: 240 mg for both males and females
  • 14-18 years: 410 mg for males, 360 mg for females, and 400 mg for pregnant females
  • 19-30 years: 400 mg for males, 310 mg for females, and 350 mg for pregnant females
  • 31-50 years: 4 to 20 mg for males, 320 mg for females, and 360 mg for pregnant females
  • 51+ years: 420 mg for males and 320 mg for females

Most people get plenty of magnesium from plant and animal foods and in certain beverages. The best foods to target for getting enough magnesium in your diet include green leafy vegetables like spinach, legumes, seeds, nuts, whole grains, and certain meat products.

However, even though most people get much or all of their daily required magnesium from food, only between 30% and 40% of dietary magnesium is absorbed by your body.

Magnesium Absorption

This leads to the next big question: why is magnesium so tough for our bodies to absorb in the first place? It all has to do with molecular structure.

How is Magnesium Absorbed?

You see, magnesium can’t stay isolated for too long. Due to its molecular structure, magnesium is a naturally unstable element, so it has to bind with another molecule to last long enough for our bodies to absorb it. Additionally, the kinds of molecules that magnesium binds with can affect how easy or difficult it is for our bodies to absorb the mineral in the first place.

Therefore, different magnesium products and supplements are distinct mostly because of the different molecules they bind to the primary magnesium.

Common magnesium binding agents include oxide, citrate, sulfate, chelate, and glycinate.

Magnesium by itself is typically poorly absorbed by the body; in the best-case scenario, your body will only absorb around 50% of consumed magnesium. However, If your body is magnesium-deficient, it may absorb a slightly higher amount than this since it will prioritize magnesium over other minerals.

Calcium and magnesium are both absorbed by the body in the same way, so they can crowd each other out and limit your body’s maximum absorption rate. With the suitable binding molecule, this can help your body absorb more magnesium in a supplement than it normally would.

Molecule Factors to Consider When Choosing a Magnesium Supplement

So, how can you tell which binding molecule is best? You’ll want to consider two major things: the size and the function of the binding molecule in question.

Molecule size matters practically because it affects how large any given supplements have to be. No one wants to take a large pill or a big spoonful of supplementary powder when a smaller, easier to swallow and digest alternative exists.

Magnesium alone is pretty small, but larger and clunkier molecules can force any resulting supplement to be much bigger than you might expect. “Magnesium by weight” is a description of the magnesium’s weight relative to any binding molecules.

For instance, magnesium by weight is higher in a supplement of magnesium oxide since oxygen is a smaller molecule than magnesium. If it's bonded to a molecule like a glycine, which is used in magnesium glycinate, the magnesium by weight is lower as the glycinate is significantly more prominent than the primary magnesium molecule.

The bottom line: certain molecules are more manageable for our bodies to absorb due to their size or other chemical factors. This plays a key role in whether magnesium citrate or magnesium oxide is a better choice for your wellness needs.

The other big factor to consider is the function of the binding molecule. For example, oxygen, as used in magnesium oxide, is beneficial for bodily tissues. Amino acids used in other magnesium supplements can also be helpful, particularly for forming the protein.

However, certain amino acids might enhance or decrease the absorption rate of magnesium.

Magnesium Citrate

Magnesium citrate is the most common type of magnesium supplement. As its name suggests, magnesium citrate is a molecule connecting magnesium with citric acid: the same acid found in citrus fruits gives them their sour flavor.

Depending on the supplement you choose, the citric acid could be synthetic, or it could be natural. Citric acid is frequently used throughout the food industry as a flavor enhancer and as a preservative.

Why use citric acid?

Because it makes magnesium more bioavailable or easily absorbed by your digestive tract. Your stomach and intestines can more easily absorb the citric acid and the magnesium along with it.

Most magnesium supplements with citric acid, therefore, are taken orally to replenish low magnesium levels.

However, magnesium citrate features lower magnesium levels by weight ratio compared to magnesium oxide. The citric acid molecules are significantly larger, so any given magnesium citrate capsule will contain less magnesium when compared to an equivalent weight magnesium oxide capsule.

What does this mean practically?

Suppose you need a certain amount of magnesium added to your daily diet through a supplement. You’ll have to take more magnesium citrate capsules or powder to get the same amount of magnesium into your body (though not necessarily absorb it) as you would with magnesium oxide.

What It’s Used For

Magnesium citrate is a popular magnesium supplement as it may provide a natural laxative effect. With the correct dosage, magnesium may help to relieve constipation and similar digestive tract disorders or issues.

Naturally, this does mean that magnesium citrate is not the best choice if you suffer from loose bowel issues, including IBS or irritable bowel syndrome.

Additionally, magnesium citrate may also have calming effects when it comes to mood and emotional balance.

Magnesium Oxide

Magnesium oxide is another common form of magnesium supplement. It’s technically a type of salt that forms when you combine oxygen with magnesium. As a result, it takes the form of a white and powdery substance, although you can find magnesium oxide supplements in both capsule and powder varieties.

Magnesium oxide is distinct from magnesium citrate based on its molecular structure. It is not as easily absorbed by your body’s digestive tract compared to magnesium citrate.

As touched on above, magnesium oxide necessarily has a higher magnesium by weight ratio compared to magnesium citrate. There is more magnesium in a given magnesium oxide capsule than an equivalent weight magnesium citrate capsule because oxygen is a pretty small, stable molecule.

Therefore, a single magnesium oxide capsule might contain a higher concentration of magnesium. But remember that the absorption rate matters.

Here’s an example:

  • Say that you have a magnesium citrate capsule with 5 mg of magnesium. You also have a magnesium oxide capsule with 10 mg of magnesium
  • The magnesium oxide capsule will only be absorbed by about 50% at most, so your body will likely only get between 5 and 6 mg from the consumed capsule
  • On the other hand, the magnesium citrate capsule will be absorbed at a rate of about 70% to 80%. With a given 5 mg capsule of magnesium citrate, your body will absorb around 4 mg of the magnesium

As you can see from the example above, the magnesium citrate capsule actually allows your body to absorb more magnesium per capsule than magnesium oxide. Were you to take two capsules of both supplements, the discrepancy would become even more dramatic.

This is the main reason why many people looking to reduce their magnesium deficiency typically choose magnesium citrate instead of oxide. It’s simply better for getting more magnesium into your cells quickly.

What It’s Used For

Magnesium oxide is well-known enough that it’s a primary active ingredient in various over-the-counter medications for constipation relief. But it isn’t normally used to treat magnesium deficiency the same way that magnesium citrate is.

There’s additionally some evidence that magnesium oxide may be able to provide some short-term relief for a variety of uncomfortable digestive systems like indigestion, heartburn, and more.

Which Type of Magnesium Supplement Should You Take?

The biggest difference between these two types of magnesium supplements is this

  • Magnesium citrate is more readily absorbed by the body, and can therefore be used as a mild laxative.
  • Magnesium oxide is not as easily absorbed by your body but might be more useful for treating other issues like indigestion or potentially migraines.

Magnesium deficiency is marked by a variety of symptoms, including muscle twitches, indigestion, weight gain, and more. Therefore, the best way to decide which magnesium supplement is right for you is to consider your issues at hand and speak to your doctor about potential magnesium deficiency.

Other Types of Bonded Magnesium Supplements

There are a variety of other forms of bonded magnesium, either as supplements or as other products. Each of these, just like magnesium citrate and magnesium oxide, carries different potential benefits and downsides.

  • Magnesium chloride is another type of magnesium salt that uses chlorine instead of oxygen. This is a naturally unstable element that can then bind strongly to other elements like sodium and regular magnesium to form different salts. Like magnesium citrate, magnesium chloride is easily absorbed by your digestive tract. It is sometimes used to temporarily relieve various digestive discomforts like heartburn and constipation.
  • Magnesium lactate is magnesium bonded to lactic acid: the same acid produced by your muscle and blood cells and which is used as a flavoring agent and preservative. Magnesium lactate is easily absorbed by the body and may be a prime choice for individuals who need to take lots of supplementary magnesium based on a doctor’s recommendation.
  • Magnesium malate is magnesium bonded to malic acid, which is a natural acid found in wine and associated fruits. It’s a sour taste in acid and is typically used as a preservative or flavor enhancer in food products. Magnesium malate is absorbed quite well by your digestive tract, so it may be a good choice for replenishing low magnesium levels.
  • Magnesium taurate combines magnesium with an amino acid called taurine. Both of these minerals can play a role in the regulation of your blood sugar level, so this particular supplement can help to support healthy blood sugar levels and healthy blood pressure.
  • Magnesium sulfate combines magnesium, oxygen, and sulfur. You probably already know this by another name: Epsom salt. It looks quite similar to table salt and can be consumed to treat constipation, but it's most often used in bathwater as a dissolving mineral to soothe aching muscles, relieve stress, and more.
  • Magnesium glycinate is formed when you bind magnesium to glycine, another amino acid. This amino acid is critical for protein construction and can be found in a variety of foods like fish, dairy, legumes, and meat products. Magnesium glycinate can be easily absorbed by your body and may have calming effects.

There’s been a lot of research and experimentation done on magnesium and binding various appropriate minerals to help stabilize the element and make it more effective or absorbable by your body.

Can’t decide which form of magnesium is best for you?

You could try a versatile supplement like Healthy Directions’ Magnesium Broad-Spectrum Complex. Rather than use just one version of bonded magnesium, our supplement experts decided to formulate a top-tier magnesium supplement that features four versions instead.

This supplement provides magnesium citrate, magnesium glycinate, magnesium taurinate, and magnesium orotate for maximum absorption by your digestive tract. As a result, every capsule you take should be absorbed quickly and thoroughly for a total of 400 mg of magnesium per day.

It’s still important to speak to your doctor at length before taking any magnesium supplement so you know which of the above choices is best for your unique needs.


Ultimately, many types of magnesium supplements can be effective solutions for treating magnesium deficiency or a variety of other health issues. But between magnesium citrate versus magnesium oxide, magnesium citrate is typically chosen as the more effective and easily absorbed choice.

As magnesium citrate can boost the bioavailability of magnesium by between 20% and 30%, it’s a top-tier choice if you want to make sure that you get as much magnesium in your system as possible, either to replace the magnesium you should be getting from your diet or because of associated conditions.

Still, magnesium oxide might be a better choice based on your unique needs and bodily chemistry. As mentioned above, you should speak to your doctor before starting any serious magnesium supplementary regimen. They can advise you about the best course of action based on tests or your health history.

At Healthy Directions, we offer a variety of magnesium supplements and can provide some assistance in learning materials as you dive deep into the details of magnesium deficiency and supplementary options.


Healthy Directions Staff Editor