Magnesium: Deficiencies, Health Benefits, and Supplements

When you supplement with most micronutrients, you don’t feel a significant difference, even though they make a difference. That’s not the case with magnesium. I’ve received numerous testimonials from clients and members after supplementing with it regularly.

Once you understand all it does for your metabolism, which forms make the most difference, and how much you should take, you can start experiencing the benefits as well.

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At least two-thirds of adults get less than the recommended dietary allowance (RDA) of magnesium: 400-420 mg for men and 310-320 mg for women. It is the second-most-common micronutrient deficiency, next to vitamin D.

Why is magnesium so important?

Magnesium plays a role in more than 600 enzymatic reactions, impacting almost every system in the body.

At any given time, you store about 25 grams, or a little less than an ounce. You store about half in your bones and half in your organs and tissues, while about one percent remains available in your blood.


Those with low levels of magnesium are more likely to have elevated C-reactive protein (hs-CRP), the main marker of systemic inflammation. Systemic inflammation contributes to everything from heart disease and degenerative disease to increased risk of infections, including COVID-19. Increasing levels back to normal reduces C-reactive protein levels.

Energy production

Magnesium aids in energy production by:

  • Assisting with the extraction of energy from food
  • Supporting proper utilization of amino acids, fat, and carbohydrates
  • Aiding in the production of adenosine triphosphate (ATP), the energy currency of every cell in the body
  • Aiding in nerve impulse conduction
  • Assisting in the utilization of other micronutrients, including B-complex vitamins, and vitamins C and E

Blood sugar and insulin sensitivity

Magnesium supports normal blood sugar levels and is needed for proper insulin metabolism. Those with insulin resistance, type 2 diabetes, and/or metabolic syndrome are often deficient. As we’ve seen in 2020, insulin resistance and diabetes are risk factors for severe viral infections, including COVID-19.

Taking magnesium alone won’t bring blood sugar and insulin levels back to normal. It still requires a well-designed strength training program, a lower-carb or ketogenic diet, and possibly medication. But the research shows it’s very difficult to maintain optimal blood sugar and improve insulin levels without addressing the need for magnesium.

Muscle function

Magnesium is essential for muscle contraction. Low levels compromise nerve conduction, which limits muscle contraction, reducing muscle strength and power. Opposite contraction, it is also necessary for muscle relaxation. Not surprisingly, supplementation often helps reduce cramps and restless leg syndrome. It may also help with normalizing high blood pressure.

Bone health

Osteoporosis risk jumps when levels decline. Though calcium plays a role in bone health, it’s helpless without sufficient vitamin D and K, plus magnesium. Vitamin D alone isn’t as helpful for health without magnesium either, as the mineral is necessary for vitamin D metabolism.

Depression and anxiety

Some believe the neural damage brought on by low magnesium diets can lead to feelings of depression.

Magnesium insufficiency lowers serotonin, which can also contribute to depression. This explains why many people experience a calming effect from magnesium.

Researchers found that taking 125-300 mg with each meal and at bedtime reversed symptoms of depression in those who have low-magnesium related depression.

It’s not just depression though.

Low magnesium, or even an excess intake of calcium, can lead to:

  • agitation
  • anxiety
  • irritability
  • confusion
  • sleeplessness
  • headaches (including migraines)
  • attention deficit hyperactivity disorder (ADHD)

Learning and memory

Low magnesium may accelerate the progression of neurodegenerative diseases like Alzheimer’s and Lewy Body dementia. It controls synaptic plasticity, which affects learning, memory, and cognitive function.

…all elements of the limbic–hypothalamus–pituitary–adrenocortical axis are sensitive to the action of Mg. Magnesium has also been demonstrated to suppress hippocampal kindling, attenuate the release of, and affect adrenocortical sensitivity to, adrenocorticotrophic hormone (ACTH), and may influence the access of corticosteroids to the brain at the level of the blood brain barrier via its action on p-glycoprotein.”

Boyle NB et al.

Exercise and sports performance

Animal studies show that deficiency increases free radical production during exercise.

Physical stress also increases the use of magnesium, making competitive athletes and fitness enthusiasts more at risk of insufficiency if they don’t supplement.

Magnesium is necessary for:

  • optimal muscle contraction
  • immune function
  • hormone production
  • cardiovascular function

All that said, there doesn’t seem to be a benefit to excessive intake. Once you reach an optimal level, taking more doesn’t create an ergogenic effect.

What causes low levels?

If you don’t consume enough through diet or supplements, you’ll remain deficient. Food processing strips most of the minerals found in grains, and fortified foods contain minimal amounts of poorly absorbed forms of minerals.

Also, even the best multivitamins rarely contain enough, because the most bioavailable form of the mineral takes up so much space.

Sugar consumption increases the use of magnesium. So does excessive physical or mental stress.

Proton pump inhibitors like Nexium® and Prevacid® and antacids decrease magnesium absorption, while loop and thiazide diuretics increase excretion.

Fluoride, commonly found in tap water, and excessive zinc (>142 mg/day) reduce magnesium absorption as well.

Though higher-fiber intakes are generally considered healthy, partially fermentable fibers like hemicellulose, or non-fermentable fibers like cellulose and lignin can also interfere with absorption.

Exercise increases magnesium excretion, which may increase daily requirements by 10-20%

Lastly, even if you met the Recommended Daily Allowance, that’s still not an optimal amount. The RDA is set at a level where most people would avoid deficiency symptoms, not a level where they’re getting optimal amounts of micronutrients.

How to Increase Magnesium Through Diet

You can get some magnesium from foods. The foods with the highest concentrations include:

  • Unprocessed whole grains
  • Dark leafy greens
  • Beans
  • Legumes
  • Certain types of nuts

Also, protein, medium-chain triglycerides (MCTs), and low or indigestible carbohydrates like resistant starch, oligosaccharides, and inulin, enhance the mineral’s absorption.

However, even with a good diet, you probably won’t get enough from food alone. That brings us to supplements.

How to Increase Levels with Supplements

Supplements are available in a variety of forms, which makes it confusing to pick the right one.

I’ll briefly touch on your options, and then share with you what I use and recommend.

Organic vs Inorganic

When describing minerals, “organic” doesn’t have the same meaning you’re familiar with as it relates to food.

Magnesium isn’t found on its own in supplements. It is bound to another molecule or compound such as a salt or an amino acid.

When magnesium is bound to a carbon-containing molecule, it’s considered “organic.” When it doesn’t contain a carbon atom, it’s considered inorganic.

“Organic” magnesium is not better in this case, so don’t be fooled by a product that boosts “Organic Chelate.”

All forms, if you take enough, should raise blood, tissue, and brain levels. However, some forms are more bioavailable than others, so you can take less and get more into your blood and tissues.

The Best Magnesium Supplements

The following table includes numerous forms and their primary benefits. However, I usually recommend the first two forms as they are the most bioavailable and well-supported in research. If you use too much, especially too much of the low-quality forms, it can lead to one well-known side effect: loose stools or diarrhea.

Magnesium BislycinateBound to the amino acid glycine, this form is the most bioavailable
Magnesium ThreonateThe only form of magnesium that crosses the blood-brain barrier so it has a significant impact on sleep and cognitive function
Magnesium CarbonateHelpful for those with indigestion or acid reflux
Magnesium ChlorideCommonly recommended for supporting detoxification and kidney function
Magnesium CitrateHelpful with constipation as it is a mild laxative
Magnesium MalateCan be helpful for those with fatigue as malic acid is involved in ATP production and is more bioavailable than most forms
Magnesium OxideMost common form in over-the-counter constipation medications
Magnesium SulfateAlso known as Epsom Salt, this magnesium is often added to a bath, but can also be used internally, though it does have a laxative effect like magnesium oxide

Most of the best multivitamins include magnesium glycinate and/or malate.

Which supplement should you use?

I use and recommend Thorne Magnesium Bisglycinate as part of the Foundational Five (highlighted below). This form is the best-absorbed mineral chelate. As it is bound to the amino acid glycine, it also:

  • supports digestive function
  • supports healthy joints
  • calms the mind
  • supports restful sleep

A single-serving dose of magnesium is 200 mg, though some people need two to three doses a day initially.

For those who struggle with sleep or need additional cognitive support, I recommend magnesium threonate in addition to bisglycinate, but not in place of it.

Magnesium-L-threonate, developed by scientists at MIT, crosses the blood-brain barrier, and increases brain levels of the mineral.

Animal research shows it improves learning abilities, working memory, and short and long-term memory. A mouse model of Alzheimer’s disease showed that threonate supplementation prevented or reversed synapse loss and memory loss. In older adults with existing cognitive problems, supplementing increased brain levels, as expected. They also experienced improvements in executive function, memory, and problem-solving abilities. Contact me if you’re interested in magnesium threonate.

Thorne Magnesium Bisglycinate

An ideal formula for active individuals wanting to unwind. Magnesium Bisglycinate is a lightly sweetened powder that is well-tolerated and well-absorbed.* NSF Certified for Sport®