Supplementing with magnesium should be the easiest decision to make, because there are substantial potential benefits and no downside.

Magnesium is a chemical element, a mineral, common enough that the cost is negligible.  The kidneys easily excrete any excess above what you need, so toxicity is not an issue*.  Magnesium is essential for life, with a part to play in the body’s electrochemistry, nerves and muscles.  Hundreds of different hormones contain magnesium.  Mg is found in many foods, especially nuts and greens.  But modern diets tend to be low in Mg, and ⅔ of Americans are getting by with magnesium levels that are sub-optimum.

Wikipedia says: “Inadequate magnesium intake frequently causes muscle spasms, and has been associated with cardiovascular disease, diabetes, high blood pressure, anxiety disorders, migraines, osteoporosis, and cerebral infarction [Ref, Ref].”

The amount of magnesium you need each day is not microscopic.  The USDA recommends 400mg (almost half a gram).  Your body’s total inventory is about 20 or 30 grams (about an ounce).

Magnesium is a chemical sibling to calcium, in the same column of the Periodic Table.  The body’s electrochemistry plays off magnesium vs calcium in the same way that it pairs sodium and potassium.  A nerve fires when sodium replaces potassium.  A muscle contracts when calcium replaces magnesium.

The ratio of magnesium to calcium is tightly regulated, and calcium supplements have been added to so many foods that, whether or not we eat dairy, most of us get more than adequate calcium.  Some but not all calcium supplements include magnesium.  In maintaining your body’s ratio calcium/magnesium, it is better to err on the side of too much magnesium, as too much calcium can lead to calcium deposits in the arteries [ref].  “Magnesium deficiency” is associated with elevated risk of arterial diseases, and that includes most people in the developed world. There is some evidence associating low Mg with the wrong kind of cholesterol in the blood (too much LDL, not enough HDL).

The biggest role for magnesium is in the energy metabolism.  Every cell takes in chemical energy as sugar from the blood, and burns the sugar in its mitochondria to create usable electrochemical energy in the form of ATP.  ATP in its active form is bound to magnesium.

The muscle protein myosin that is the source of all strength and movement, including heart contractions, has a magnesium atom at its core.

The body can get by with less magnesium, but it doesn’t function as well.  Muscles can cramp and anxiety can be higher when magnesium is scarce.  Calcium metabolism is closely linked to magnesium.  There is some evidence that magnesium deficiency plays a role in osteoporosis.  (Here is a page from Dr Lam on the subject.)

Insulin sensitivity and the sugar metabolism are the most accessible variable in controlling our rate of aging.  More than ¼ of Americans over 65 are formally diagnosed with Type 2 diabetes, and the numbers would be far larger but for the fact that loss of insulin sensitivity is considered part of “normal aging”.  Many studies have documented that higher intake of Mg helps to retain insulin sensitivity with age [for example, ref1, ref2, ref3, review].

Some people who suffer from migraines find that magnesium helps dramatically [example ref].

One study suggested enhanced athletic performance with magnesium supplementation

Life expectancy?

The definitive studies have not been done, but there is suggestive evidence that more magnesium might be associated with longer life.   Here are two studies from Sweden [Ref1, Ref2] that found a connection between magnesium in drinking water and protection from cardiovascular disease.  This is a French study that found lower overall and cardiac mortality rates in people who had higher levels of Mg in the blood.  In this more recent study from Germany, peope with low blood levels of Mg had mortality rates 7 times higher than people with “normal” levels.  (Remember that “normal” is in the minority.)  Here is a Finnish study, however, that failed to find a cardio-protective effect from Mg in the blood.  In this Taiwanese study, the highest levels of Mg in drinking water were found to protect against cancer.

This is important work, and I don’t know why it hasn’t been pursued with more detail.  It these results are correct, there is no cheaper or easier way to better health.


Epsom Salt

Epsom salt=magnesium sulfate is cheap enough that you can pour it into your bath.  Absorption through the skin can be all you need, if that is your preferred delivery.  If you eat epsom salt, a bag costing a few dollars will last a year.  The only reason not to eat epsom salt is the taste.

Epsom salt is sometimes used as a laxative at dose of 1-2 tsp.  A daily dose of magnesium is about ¼ tsp.


Magnesium and brain aging

There is a separate line of research associating brain aging with lower magnesium in the brain.  This is newer, less well established, and has been promoted by Life Extension Foundation the last few years.  There is an expensive form of magnesium, called magnesium threonate (or MgT), that is more available to the brain.

Supplementing with MgT has been associated with enhanced memory and more effective learning in rats.  In a mouse model of Alzheimer’s Disease, MgT delayed cognitive decline.  There is theoretical support for the effect that invokes the NMDA receptor.   The only human study that I’ve been able to find reported abatement of fear and anxiety with MgT.  Can the memory results be replicated in humans?  I have written to Guosong Liu, now at the medical school of Tsinghua University in Beijing, who originally developed MgT while at MIT. The English version of his academic web site says, “Human clinical trials based on our discoveries are undergoing to translate the knowledge from our research to new therapies for the treatment of neurological disease with decline of memory function and psychiatric disorder such as anxiety and depression.”

The bottom line

If you want to read even more effusive support for magnesium supplements, visit the Center for Magnesium Education and Research.  You can try to have your blood levels tested, but the correlation between blood levels and Mg available in tissues is not so reliable.  The easiest thing to do is add Mg to your supplements.  It’s not going to hurt you, and it may do a great deal of good.

I have recently discovered as a source for information about common and uncommon nutritional supplements.  It is encyclopedic in scope, well-indexed, and seems to contain straight, unbiased summaries.  Everything is linked to primary references. Put “magnesium” into their search box and this is what you’ll find. They have digests and cross-indexed sumaries for sale as PDFs, but I appreciate the fact that all their basic research is available on-line at no cost. has already made my work easier.


* There is such a thing as magnesium toxicity, hypermagnesemia, but it is limited almost exclusively to people who have kidney disorders and are being medicated with pharmacological doses of magnesium.

14 thoughts on “Magnesium

  1. Hi there

    nice to hear about magnesium-
    I have been hearing form people taking high dose Vitamin D3 along with high dose K2. Maybe 600 or so people so far…
    A few people have a bad reaction to high dose d3 and or k2….and in these rare cases it usally turns out they have an underlying magnesium deficiency which is excaberated by high dose d3 and k2 which likely causes magnesium to be seqauestered in the bones and taken out of the blood and soft tissues..
    In these rare cases what happens? heart racing…arrythmias….large fluctuations in blood fact I was contacted by one lady in germany who took high dose d3 for a week and ended up in the hospital with heart arrythmias…the Dr wanted to operate and install a pacemaker
    I told her no!!!!..take high dose magneisium for a week and then restart the d3/k2 program..the magnesium quickly cured her symptoms..There are other stories like this too…

  2. I think modern foods are low to Mg becuase there are processed a lot meaning food loses its natural composition.

    A lot of people myself included dont know about the importance of Mg in the human body and what lack of it actually means for your body.
    But is taking Epsom salt for you? besides the taste. Is the salt content in it not harmful to you?
    Because i’ve heard stories whereby people are advised to reduce their salt intake.

    • Epsom salt contains no “salt”. It’s an ambiguity in the chemical name. The part of salt that people objected to was the sodium. There is sodium in table salt, but not in epsom salt. Epsom salt has no sodium.

      But I also encourage you to rethink sodium and table salt. The latest thinking is that all the years of doctors telling people not to eat salt were completely wrong. Read more here and here.

  3. For some reason I always notice a tiny little bit of sensation like the palms of my hands are somewhat numb after a dose of magnesium (like 20 mins afterward). I also can’t take it at night because it seems to keep me up. I’m a COMT++ and overmethylator so it’s possible I need to be careful with supplementation even when I feel like I should be taking it. Also, even if you take the chelated form do you think it potentially feeds biofilms in the gut?

  4. It’s interesting to note that many prominent Paleo and Weston Price writers have being pushing magnesium for years.


    Weston Price:

    I also find that taking some before bed time is a good idea as it helps the body sleep.

    Anyways, some supplements of MG are work better than others it looks like. Good cheap ones are magnesium citrate and malate – otherwise go for the chelated ones tied to an amino acid or try dermal magnesium.

    The oxide stuff is not good.

  5. It is actually the first time that I see all these attributes of magnesium and I am shocked that this information is not on the front page of every newspaper? According to the World Health Organization less than 30% of adults consume the correct amount of magnesium (1). It is obvious that small changes in lifestyle and food choices can lead to life without pain. Is this the reason that government and corporate health organizations remains silent? It might just cause them to lose money if we life healthier.

    (1)Combs GF, Nielsen FH. Health significance of calcium and magnesium: Examples from human studies. In: World Health Organization. Calcium and Magnesium in Drinking Water: Public health significance. Geneva: World Health Organization Press; 2009.

  6. Hi Josh,
    I supplement with magnesium citrate, do you know how less “brain availabilty” it has compared to threonate?

    • There is just that one study I cited, by an MIT doc who is now in Beijing. The results of the study were very clear that threonate works and other forms of Mg don’t work, but it’s just one study.

      • Thanks!
        (would that doc by any chance appear to sell threonate or be kind of friends with a lab who does ? ;p )

  7. A whole lot of enzymes use magnesium as a co-factor.
    Since many magnesium salts are very soluble in water, I imagine most farmland is deficient, unless the farmer is adding magnesium with his fertilizers.

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