Minerals: Magnesium (About)

Magnesium Flakes

by Cat, July, 2007; Updated Aug 2017 re: “chew chew chew” for mineral absorption. Image, right, from Step to Health (8)

Magnesium is a very important mineral for humans, but it is not so easily absorbed from foods or most supplements. For this reason, many of us are deficient, causing symptoms such as constipation and leg cramps, or even more serious symptoms such as insulin resistance, type-2 diabetes or high blood pressure.

It is hard for us to absorb magnesium from the foods we eat or from most supplements we take internally, but there are ways to get around this problem, as discussed in the article.

About Magnesium

Magnesium is the 4th most common mineral in our bodies. Here’s some details:

Magnesium (Mg) is an essential common mineral   

Our bodies need certain minerals for proper functioning of enzymes, co-enzymes, nerve impulses, bone tissue, etc.. The most common of these essential minerals are needed in significant quantities in our daily diet.

Why magnesium is important

Here are some of the key reasons (1):

  • It is the fourth most abundant mineral in your body
  • Exists in over 300 different bodily enzymes
  • Is found primarily in your bones (half of your total body magnesium)
  • Plays a role in your body’s detoxification processes
  • Aids your energy metabolism and protein synthesis
  • Helps guide a large number of physiological functions
  • Is required by glutathione (the “master antioxidant”) for synthesis
  • Is especially valuable for supporting your brain health

See also:

Magnesium function

It is essential for more than 300 enzymes to function, including the enzyme that makes glutathione, the major detox enzyme. Hexokinase and glucose-6-phosphatase are just two enzymes that are activated by magnesium.

Several organs cannot function without magnesium, including the brain, bones and muscles. The latter is one reason why fatigue is a symptom of magnesium insufficiency. It has also been implicated in many disorders including hypoglycemia, insulin resistance, asthma and bowel disorders, along with many others. See Mercola: The Miracle of Magnesium (1A) and Problems Due to Magnesium Deficiency (1B) for more.

RDA for magnesium

“The recommended dietary allowance for magnesium is 310 to 420 mg per day depending on your age and sex, but many experts believe you may need 600 to 900 mg per day, which is more in line with the magnesium uptake during the Paleolithic period.” (from Mercola (2b)). I totally agree with this, as that is how much I have to take to avoid having another heart-attack-like episode (muscles in arterial walls spasm, temporarily blocking blood flow), because magnesium relaxes these muscles to avoid the spasm. 

Common food sources for magnesium

Molasses, honey, legumes*, tuna, bone meal, nuts* and seeds*, cocoa, whole grains*, dried apricots, dark green leafy veggies**, sea vegetables. [Those marked with * or ** need special treatment to make the magnesium available for absorption.]

‘* Sprouting or presoaking legumes, nuts and whole grains makes their magnesium available for absorption.

‘** Braising dark green leafy veggies (sautéing in oil, then steaming in a bit of water) frees the magnesium from the phytates that bind it.

See also Magnesium Supplements and Topically Applied Magnesium, below.

Foods rich in magnesium

This chart is from Mercola (1):

Magnesium deficiency

This list is from Dr. Jockers’ Nov 2021 article: 10 Signs of Magnesium Deficiency (13); those items in color are not included in either of the next two lists from Mercola. Check out Dr Jockers’ article for more detail.

  1. Poor cognitive processing, such as brain fog
  2. Headaches and chronic migraines
  3. Constipation and related disorders such as IBS
  4. Fatigue (physical, mental and emotional)
  5. Poor sleep quality 
  6. Muscle spasms and cramping [such as charley-horses]
  7. Pain and soreness, including fibromyalgia
  8. Irregular heartbeat, or heart arrhythmia 
  9. Numbness and tingling [this is one I have in my feet, especially when I go to bed; I treat this by rubbing “Magnesium Oil” on my feet before bed.]
  10. Mood and behavioral disorders, such as ADD/ADHD, anxiety, irritability, bipolar disorder and more

Some early signs of a potential lack of magnesium in your body include. 

This list is from a Mercola 2017 article (1b):

  • Loss of appetite and headache
  • Nausea and vomiting
  • Fatigue and weakness

Symptoms of long-standing magnesium deficiency:

I’ve divided the original list from a Mercola 2019 article (1g) into two categories:

Those I have experienced:

  • Constipation
  • Charley horses
  • Numbness or tingling in your extremities
  • Insulin resistance
  • “False” heart attack caused by spasming of arteries, temporarily blocking flow of blood

Those I’ve not yet experienced:

  • Type-2 diabetes [tho I have been a pre-diabetic in the past, before I learned about my insulin resistance]
  • High blood pressure
  • Heart disease (after my “false” heart attack, my cardiologist sent a small camera up one of my veins to my heart, and did not find any signs of plaque build-up or heart disease).

Magnesium absorption

This is a problem for most people – even though we may eat enough foods rich in magnesium, if we have trouble absorbing it, we will show signs of deficiency.  Ways to increase absorption:

  • One of the most important things we can do to improve absorption is to chew-chew-chew our foods. 
  • Sufficient dietary fat (good fats) and fiber are also important;
  • Magnesium from meats is easier to absorb than that from plants;
  • You need sufficient bifidobacteria in your gut microbiome;
  • Braise your dark green veggies (sauté in fat, then add a bit of water to steam them), and soak your seeds (including legumes, nuts, grains and other seeds) overnight to break down phytates that otherwise bind minerals making them unavailable for absorption.
  • Increase your vitamin D, preferably by spending time in midday sun, but supplementing with vitamin D3 also helps;
  • If you take magnesium supplements, take them with food, and ensure you have sufficient stomach acid (you can boost this by taking betaine-HCL or apple cider vinegar with your meal);
  • Avoid caffeine (coffee, tea, chocolate) and alcohol with meals, as both interfere with mineral absorption.

Other reasons for magnesium deficiency (1)

Types of food you eat – If you consume mostly non-organic foods, their magnesium levels may be depleted due to chemical fertilizers and pesticides. Levels of magnesium in the soil determine what’s in the food.

Medication – Certain medicines can contribute to a shortage of magnesium within your body.

Supplemental magnesium

Mercola (2D) writes, “The recommended dietary allowance for magnesium is 310 to 420 mg per day depending on your age and sex, but many experts believe you may need 600 to 900 mg per day, which is more in line with the magnesium uptake during the Paleolithic period.” This higher amount is likely due to dietary magnesium being hard to absorb.

There are many different types of magnesium supplements (not all possibilities are listed here):

  • magnesium ascorbate,
  • magnesium aspartate,
  • magnesium chloride,
  • magnesium citrate,
  • magnesium hydroxide (Milk of Magnesia),
  • magnesium oxide,
  • magnesium sulfate (Epsom Salt),
  • magnesium threonate (believed to cross the blood-brain barrier).

MgCl2 (magnesium chloride)

The main magnesium supplement I take (a compounded prescription) is 80% magnesium chloride solution (MgCl2). I also use Magtein (mag L-threonate) off and on, and magnesium aspartate if MgCl2 is causing diarrhea.

  • 2017 update: I’ve developed a food sensitivity to these forms of magnesium, so stopped taking them temporarily, then reintroducing MgCl2 slowly. 2019 update: The only form I’m currently taking is MgCl2 solution, or the topical form when my food sensitivity acts up.
  • 2019 update about the food sensitivity: My naturopath had me take myo-inositol to reverse my insulin resistance (by re-activating/restoring insulin receptors on cell membranes). Not only did it help with that, but its main job of stabilizing cell membranes also cleared-up my food sensitivity to MgCl2 (as well as other food sensitivities).

See: Supplements I use, Magnesium (About), and Magnesium Chloride, 80% Solution, for more about MgCl2.

Magnesium sulfate (Epsom salt)

See also topically-applied magnesium, below.

Mercola (1F) sites the following benefits for taking most forms of magnesium internally, including mag sulfate:

  • Relief from constipationMost magnesium supplements, including mag sulfate, are known for their laxative effect, and magnesium sulfate has been found to be a helpful treatment for constipation by pulling more water from your body into the colon. mag chloride is also helpful to relieve constipation.
  • Improved muscle recoveryMagnesium is responsible for oxygen uptake, energy production and electrolyte balance, among other benefits. Increasing magnesium intake may help improve physical activity and recovery.
  • Relaxing muscles Research suggests that the muscle-relaxing properties of magnesium work by inhibiting calcium influx into the cytosol.
  • Better cognitive functionMagnesium deficiency has been linked to various neurological pathologies such as migraines, depression, epilepsy, stroke, traumatic brain and spinal injuries and Parkinson’s disease.

The same article also sites the following benefits specifically for supplemental magnesium sulfate:

  • Treatment for preeclampsia (a complication that may occur during pregnancy). Intravenous administration of mag sulfate in a hospital setting will help reduce risk of seizures in the mother’s body, and minimize further complications.
  • Ease asthma symptoms —  Mag sulfate may provide immediate relief by inducing relaxation in the brachial smooth muscles.
  • Improvement of insulin sensitivity.

Topically applied Magnesium

Sept 2018: I’ve developed a food sensitivity to my 80% solution of MgCl2 taken orally, and I can’t seem to heal that sensitivity. So I am going to try topical application for part of my daily requirement. That is, I’ll take a smaller dose orally, and make up the difference with topical application.

There are several methods of taking magnesium through the skin, including oil spray, baths, foot-soaks, massage, lotion and deodorant. Best places to apply for maximum absorption: underarms.

The following describes two different but related methods: Epsom Salt (MgSO4) bath or rub; and Magnesium Oil (MgCl2) sprayed on skin.

Topical Epsom Salt

There are two main ways to use epsom salt topically:

  • an epsom salt bath (1 cup of the salt per bath), or
  • a highly concentrated rub.

Here’s instructions from Mercola for the rub (2D) :

“Prepare a supersaturated solution of Epsom salts by dissolving 7 tablespoons of the salt into 6 ounces of water and heating it until all the salt has dissolved. I pour it into a dropper bottle and then apply it to my skin and rub fresh aloe leaves over it to dissolve it. This is an easy and inexpensive way to increase your magnesium and will allow you to get higher dosages into your body without having to deal with its laxative effects.

Optimizing your magnesium level is particularly important when taking supplemental vitamin D, as your body cannot properly utilize the vitamin if you’re your magnesium is insufficient. (10, 11). The reason for this is because magnesium is required for the actual activation of vitamin D (1E).”

Topical Magnesium Oil

This is not really an oil, but it feels oily when you rub it on the skin. It is actually a water solution of magnesium chloride (MgCl2.6H2O) flakes (see top of article for photo of the flakes (8)). There are many brands of the spray; the one I’m currently using is Life-Flo Pure Magnesium Oil (brine) (9).

Concentration of Mg in the dry flakes by brand (note, all contain other trace minerals). Here’s two examples:

  • Ancient Earth: 100 mg Mg per 1 ml solution (6 sprays) – they specified this.
  • Life-Flo Pure:  my calc: 25 mg Mg/ml solution if the salt is hydrated, or 5.4 mg Mg/ml solution if salt is not hydrated (my calculation; they don’t specify which form of MgCl2).

Or you can make your own by mixing ½ cup of the flakes in ½ cup filtered, boiled water; see Dr. Axe’s article (3) for details. He provides lots of good information about magnesium oil., including making an effective deodorant from the oil.

Magnesium chloride solution

I first learned about the important benefits of “mag chloride” when I was living in Portland OR in the 1990s, from Dr. Bernie Bayard, my naturopath/acupuncturist. He referred me to an article by Walter Last in Australia on the benefits of Magnesium Chloride: MgCl2-WalterLast.pdf (this is my pdf as a direct copy of the original – thank goodness I made that, as Walter’s link (4) is no longer available). Other articles of interest include:

  • Magnesium Chloride Hexahydrate Therapy (5) on its benefits (this uses 125 ml 2.5% solution daily for adults, which provides same amount of Mg as 8 ml 80% solution daily;
  • How to Extract Magnesium Chloride from Unrefined Sea Salt (6);
  • Magnesium Chloride Hexahydrate Therapy (7).

The solid salt form is a mix of small flakes, rather than being a powder like most other salts. It is a hexahydrate, meaning that each mag-chloride molecule is bound to 6 water molecules; the molecular formula is MgCl2.6H20. Walter Last recommends taking an 80% solution of the flakes in water. Dr. Bayard made up the 80% solution for me, and it worked miracles!

  • All my life, since infancy, I’d been horribly constipated and had to have regular enemas. But the 80% MgCl2 solution changed all that. I mixed ½ tsp (2.5 ml) of the solution in a glass of water upon getting up every morning and before bed every night, and that did the trick.
  • It improved my digestion of proteins by increasing gastric acid (hydrochloric acid) in my stomach.
  • I’ve had other benefits from this solution as well, but it’s been so long since they first happened that I do not recall them at this time.

I’ve modified my dosage a bit over the years; currently I take 2 eyedroppers-full of mag chloride added to a glass of water upon rising, at mid-day, and just before bed at night; for total daily dosage of 570 mg/day (95 mg/dropperfull, 6-times).

Another popular way to take mag chloride solution is a spray applied topically to the skin in the underarm area, or on the belly: spray it on, then gently rub it in. Your body will absorb it directly into the blood stream this way.

See separate article on Magnesium Chloride 80% Solution for more details < update link (this is the edit link)


  1. Mercola: products.mercola.com/magnesium-supplement/
    1. articles.mercola.com/sites/articles/archive/2004/08/07/miracle-magnesium.aspx; This link goes to: articles.mercola.com/vitamins-supplements/magnesium-citrate.aspx (Title has been changed)
    2. articles.mercola.com/sites/articles/archive/2017/09/06/magnesium-deficiency-effects.aspx,
    3. articles.mercola.com/sites/articles/archive/2017/08/13/heal-mental-disorders-with-nutrition.aspx
    4. articles.mercola.com/sites/articles/archive/2018/09/24/overlooked-lab-tests.aspx  
    5. mercola.com/Downloads/bonus/vitamin-d/report.aspx
    6. articles.mercola.com/vitamins-supplements/magnesium-sulfate.aspx
    7. articles.mercola.com/sites/articles/archive/2019/11/18/low-magnesium-diabetes.aspx
  2. ancient-minerals.com/transdermal-magnesium/magnesium-application-use/
  3. draxe.com/magnesium-oil/ 
  4. Walter Last: health-science-spirit.com/magnesiumchloride.html
  5. arthritistrust.org/…/Magnesium Chloride Hexahydrate Therapy.pdf
  6. ehow: How to Extract Magnesium Chloride from Sea Salt
  7. MagChloride-hexahydrate therapy:  arthritistrust.org/Articles/Magnesium%20Chloride%20Hexahydrate%20Therapy.pdf
  8. Image: steptohealth.com/18-incredible-benefits-magnesium-chloride/
  9. life-flo.com/magnesium-oil.html
  10. livescience.com/61866-magnesium-vitamin-d.html
  11. livestrong.com/article/387358-vitamin-d-magnesium-interaction/
  12. Green Med Info: Safe First-Line of Defense for Clinical Depression, by Ali Le Vere
  13. Dr.Jockers: drjockers.com/10-signs-magnesium-deficiency/

About Cat

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