How Does Magnesium Supplementation Benefit You?

Why has magnesium gotten so popular recently? Perhaps you’ve heard that a magnesium deficiency is the reason you feel like crap all the time. Maybe you heard that a magnesium supplement may help alleviate anxiety, depression, muscle cramps, lower your blood pressure, and heal all sorts of health ailments because health gurus have been jumping on the bandwagon.

Well, at least they’re right that many people are deficient in magnesium, as it actually happens to be the second most common deficiency in developed countries. This is basically due to a poor diet of processed foods which is low in fruits and vegetables which supply the most easily absorbed dietary magnesium.

Does this mean you should immediately run out and get a magnesium supplement?

Not really.

You see, we believe that your nutrition should come primarily from whole foods, but a magnesium supplement may be a good idea if you have various food allergies or intolerances which make consuming rich sources of magnesium an issue. Otherwise, actually changing your diet to include more magnesium is the best strategy and will also boost the overall quality of your diet as well, no supplement needed.

We’re going to see though, that the majority of the research on magnesium supplementation and how it benefits the body is dependent on being deficient in the first place. So basically, a supplement won’t do much for someone who already has adequate magnesium stores in their body.

How Do You Determine Deficiency?


There are several types of tests for magnesium levels which can help discover deficiencies and can be ordered by a doctor.

Blood tests - while common, they aren’t very accurate since your body will regulate your blood magnesium to stay at a certain level regardless of whether or not your cells contain enough. Only about 1% of your body’s magnesium is in the blood at any time, and therefore this isn’t a good indicator.

RBC Tests - This is more accurate as it actually measures the amount of magnesium within red blood cells.

Ionized magnesium in erythrocytes - This is currently the best estimate of your body’s magnesium stores and should be considered the gold standard of tests when determining deficiency or sufficiency.

Magnesium tolerance test - This type of testing is supposed to be a free, at-home test with some simple magnesium powder and checking to see if you experience side effects. While it may be somewhat accurate in some people, the quality and form of magnesium will determine if it gives you side effects like diarrhea or not. It’s also more of an indicator of how well you absorb a magnesium supplement and how your bowels function in response. If you’re really concerned about your magnesium levels, just go get a test and stop trying to diagnose yourself!

How Much Do I Need?

For most people, it will range between 350-450 mg per day, but many people who eat a Western or Standard American Diet will be lucky to get a fourth to half that amount. If you didn’t already know to eat your fruits and may be a good time to start!

Continuing to eat junk food and relying on a magnesium supplement to avoid deficiency is not really solving any problems long term, and will just cost you extra money that you don’t need to spend. Remember: supplements can be abused like pharmaceuticals can where they are used as a bandage to cover up a more serious underlying problem. In this case, the problem is a bad diet.

If you have food allergies and/or intolerances to the best sources of magnesium in food, then a supplement can help you reach your daily target. A supplement may also be used as a tool for temporarily helping to get out of a deficiency, but shouldn’t be seen as a long term solution.

So what happens when you’re deficient in magnesium and begin to supplement? As we’ll see, the majority of the benefits are due to correcting a deficiency and so aren’t unique benefits that can apply to everyone. However, an adequate magnesium intake is essential for the following reasons.

Blood Pressure Regulation

In those with depleted magnesium levels, it appears that a supplement is able to reliably reduce blood pressure, especially in those with preexisting hypertension (high blood pressure). Some studies suggest that the overall effect may be small, and limited by overall magnesium status. Basically, a magnesium supplement hasn’t been shown to have much of an effect in people with normal blood pressure and/or normal magnesium levels.

Fortunately, many of the positive effects on blood pressure do seem to be apparent in those with diabetes, but may not apply to all. The doses typically range from 300-500 mg per day and use a variety of forms of magnesium to achieve the blood pressure regulation effect. It may be a good option to consider for those with low magnesium status who also suffer from high blood pressure, but it may not significantly lower blood pressure when the cause of hypertension isn’t due to low magnesium.

Promote Bowel Regularity

Magnesium supplements are often touted to provide relief from constipation, but this depends on the individual and the type of supplement being used. For example, milk of magnesia has been used for quite a long time to induce bowel movements because of its low intestinal absorption and tendency to bring water into the bowels. Other supplements like magnesium oxide have been shown to induce diarrhea in about 12% of those taking it at 1 gram per day.

Other forms of magnesium may also have this effect in large doses (or small doses for some people), and may depend on current magnesium status, as the body tends to absorb less magnesium when there are already sufficient amounts.

Using magnesium as a laxative over long periods of time to induce bowel movements shouldn’t be considered 100% safe, but may be a safer option than stimulant based laxatives. Anything which causes diarrhea can lead to electrolyte imbalances and may further complicate existing issues. Fixing the root cause of constipation is essential, as it tends to be more related to diet, gut health, and motility issues.

Sleep, Relaxation, and Depression

Is magnesium an all natural sleep aid and antidepressant? Well, it depends.

Magnesium supplementation has been demonstrated to improve sleep quality in elderly subjects with low magnesium status. Theoretically, it may also have this effect in other people with low magnesium status since one of magnesium’s primary roles is to counterbalance calcium channels which can cause anxiety and over-excitability when they aren’t functioning properly. We’ve heard plenty of anecdotes from clients who have seen an improvement in sleep quality who weren’t elderly, and I’ve also personally experienced slightly better sleep when supplementing magnesium (though I usually use it in combination with L-theanine!).

What does magnesium have to do with depression?

There are theories floating about that a reduction in magnesium consumption over the years is strongly correlated with an increase in depression rates. Also notable is that some antidepressants have been known to increase cellular magnesium levels, and it starts to make sense that magnesium may play a role in mitigating depression. Rats who have induced magnesium deficiency by being fed a diet low in magnesium have also exhibited an increase in anxiety and depression.

However, other evaluations have failed to find consistent correlations between magnesium levels and depression. One study even found that majorly depressed patients had significantly higher erythrocyte and serum magnesium levels when compared to those with minor depression. One study did note that 450 mg of magnesium chloride per day was as effective as 50 mg of imipramine (an antidepressant) in elderly depressed patients with type 2 diabetes.

Why are the correlations all over the place?

Because depression is a complex disorder which isn’t always dependent on nutritional factors. While low magnesium or low omega-3 status may have implications in depression in some people, it doesn’t always translate because depression can be caused by a host of issues like lack of social interaction, major life events, stress, and more. This means that while magnesium may be effective in some people, it isn’t a catch all and shouldn’t be viewed as one.

If you would like to learn more about what it’s like to have a diagnosis of a mental health disorder, check out this great article. You’re not alone and it’s more complex than you might think.

Increased Insulin Sensitivity and Lowered Blood Sugar

Diabetes, pre-diabetes, and insulin resistance are so prevalent now that we’ve been searching for alternative solutions to pharmaceutical interventions and magnesium has no doubt made the list. Like the others so far, the effects seem to be mostly dependent on correcting a deficiency, but may also happen in those with normal magnesium levels but with characteristics of metabolic syndrome.

In subjects with type 2 diabetes, magnesium supplementation which alleviates deficiency was able to help improve insulin sensitivity. This effect has also been found in those without type 2 diabetes, but who were overweight and insulin resistant even when their magnesium levels were adequate. What really blows my mind is that magnesium supplementation has also failed to find the same effects elsewhere in those with adequate magnesium levels. One study found that magnesium failed to significantly influence blood sugar control in those with type 2 diabetes.

Interestingly enough, magnesium supplementation actually appears to enhance the glucose fluctuations of exercise in both fighting athletes and triathletes. This means that maintaining good magnesium status may be crucial to athletes in regulating their blood sugar responses and may lead to a slight increase in performance.

Cramps and Muscle Pain

While magnesium depletion can be a cause of cramping and muscle pain, what does the research have to say about a supplement being used as an intervention for general muscle cramps? Unfortunately, there isn’t very compelling evidence that magnesium can alleviate cramping to a significant level. Another study on pregnant women also found that magnesium failed to reduce cramping to a significant level above placebo. One study did find a significant reduction in leg cramps in another subset of pregnant women, but the interesting thing is that a placebo was able to reduce cramping by 60% itself. Other studies have found high rates of leg cramp reduction with a placebo as well, with a failure of magnesium to significantly outperform these sugar pills.

So despite many people using magnesium for leg cramps, it appears that a placebo is able to reduce cramping severity and frequency on its own in multiple studies. Does this mean that the cramping is psychosomatic? We’re not really sure, but our theory is that since both sugar and magnesium have the ability to increase muscular hydration to a degree, that may be the reason that these effects are seen.

Cramps can also have other causes like a potassium deficiency or otherwise just general dehydration. They may also be stress related, or have many other causes that won’t specifically be addressed with a magnesium supplement. I’ve heard mixed results from my clients with magnesium and cramps where it helps some but not everyone. Based on the studies so far, it appears that magnesium works to a degree, but so does a placebo!

Headaches and Migraines

There is another interesting correlation between low magnesium levels and occurrence of migraine and cluster headaches. It appears that our rampant magnesium deficiencies can affect a lot of areas of life and correcting this may be a key player in improving overall health and quality of life. One study actually found that magnesium supplementation was decently effective at reducing migraine severity, but not frequency when compared to a placebo.

When talking about general tension headaches, magnesium hasn’t really be investigated in clinical studies, but it makes sense for those who have blood pressure related headaches due to magnesium’s positive effects on regulating high blood pressure. There are some anecdotal stories of frequent sufferers of headaches experiencing less headaches as a result of magnesium supplementation, so it may be something worth trying.

Athletic Performance

All sports competitors are looking for a way to get an edge up on the competition, and magnesium has been brought to the light as a supposed legal performance enhancer. It is suggested that physical exercise may increase the body’s need for magnesium. In older subjects, magnesium has been demonstrated to improve exercise performance slightly. It also appears to increase exercise tolerance in older people with heart disease and COPD.

When it comes to healthy young athletes, the studies are mixed. Two studies found an increase in jump performance in volleyball players, and in swim time in triathletes. Another study failed to find any significant performance increase, but this study also used magnesium oxide, a form with very poor absorption rates.

It may be that maintaining adequate magnesium levels is of the most benefit to athletes and that magnesium status may decline faster in those who engage in strenuous exercise. Increasing magnesium content of the diet or taking a supplement may be necessary for athletes to perform at their best.

Does the Form of Magnesium Supplement Matter?

We get it. Every company wants you to buy their magnesium and of course each will claim that their form of magnesium is the most highly absorbed...yatta yatta.

However, it really doesn’t matter as much as you might think. The main tip we’d give here on having a well absorbed magnesium is to avoid ones which primarily have a laxative effect like oxide and dihydroxide (milk of magnesia). Sulfate (which is epsom salt) can also have a laxative effect and may be limited by poor absorption.

Gluconate may be the most absorbable, but it doesn’t differ too much from ones like citrate and malate, which are only slightly better than orotate and aspartate. The studies mentioned in this article were able to correct magnesium deficiencies using a variety of forms of magnesium, and should show you that stressing out over which one is 2% more absorbable than another is largely irrelevant. Most of your magnesium intake should come from dietary sources anyway, and a supplement should be seen as just that...a supplement!

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There are so many food sources of magnesium that it should be easy for almost anyone to fit enough into their diet. However, some food sources like grains and beans may have limited absorption due to nutrient inhibitors like phytic acid, and therefore should be properly prepared through soaking and sprouting prior to consumption. My favorite sources are chocolate, veggies, bananas, and nuts, and I find it quite easy to meet my daily magnesium targets without a supplement. You can use services like cronometer to track how much you’re getting on a daily basis and make adjustments accordingly.  

What About Topical Magnesium?

There is currently insufficient evidence that magnesium applied to the skin will raise either blood or cellular levels of magnesium and probably shouldn’t be seen as a means of correcting a deficiency. That will occur through diet and an oral supplement.

However, magnesium baths do feel amazing and the benefits may be more related to muscular relaxation and a calm, meditative state brought about by a nice warm soak. Magnesium also feels really good externally and can help with dry skin, so it’s not like topical magnesium is completely useless. We just don’t see it as a solution to magnesium deficiency and a reliable means of obtaining higher magnesium levels in the body since the studies aren’t very conclusive and many show no benefit.

Side Effects and Toxicity

The most common side effect is diarrhea, which may be accompanied by nausea and is usually found most often with the forms of magnesium like oxide and dihydroxide which have a laxative effect. Other people may experience sedation and general uneasiness after taking large doses of magnesium (as has happened to me).

There haven’t been any reported toxic effects in normal doses so far and it appears that toxicity may be limited by absorption rates decreasing over time as a deficiency is alleviated.

Overall Thoughts


We’re sorry to burst your bubble, but magnesium doesn’t appear to be the cure all that people claim it to be. Most of the positive benefits are limited to those with deficiency, and in those without a deficiency the effects are pretty scattered and inconsistent. Is it worth taking? If you really have trouble getting in enough magnesium from your diet and intolerances prevent you from eating magnesium rich foods, then a supplement may come in handy. Otherwise, eat your fruits and vegetables!

Thanks for reading and we hope you enjoyed this article. Be sure to check out our podcast episode on magnesium on iTunes and Spotify, or by clicking here. Like us on Facebook, and follow us on Instagram for updates, and be sure to subscribe to our mailing list. Until next time, always remember that H = Health!