What are the side effects of low magnesium in your body? And what does this have to do with your brain?


For humans, magnesium is a macromineral which is a cofactor in more than 300 enzymatic reactions in the body (Kirkland et al., 2018), including in the brain. I’m not going to bore you with too much science-ese (you can always check out the references at the bottom for that). We are going to review the importance of magnesium in the diet and what can happen when we are deficient. Additionally, we’ll go into the various forms of magnesium because there are several.

Side Effects of Low Magnesium


Magnesium affects so many body processes; it’s sometimes mistaken for something else.

Here’s the list of symptoms of low magnesium:

  • Heart Arrhythmia and other irregularities
  • Fatigue
  • Brain Fog
  • Muscle cramps, twitches, and spasms
  • Anxiety
  • Memory problems
  • Mood problems
  • Migraines
  • PMS
  • Irregular sleep patterns and insomnia
  • Aches and pains
  • Depression
  • Constipation
  • Lack of appetite
  • ADHD
  • Digestive issues
  • Osteoporosis
  • Type II Diabetes

Some people have some of these symptoms. Some have no symptoms (that they know of)! The fact is, the estimated number of people deficient in magnesium is over 80% of the population unless they are supplementing. That number can vary depending on who you ask, but that’s a staggering statistic. Our farm-grown foods just don’t have the quality or quantity of nutrients they used to have due to depleted soil so it’s hard to get enough even from raw foods.

Magnesium and the Brain


So, magnesium is responsible for interacting with a receptor in the brain and blocking a bad calcium channel. When we don’t have enough magnesium, it opens the flood gates for excitotoxicity which can lead to oxidative stress and neuronal cell death. Oxidative stress creates rogue cells called free radicals, which are atoms with one or more unpaired electrons floating around and looking for other electrons to pair with. They don’t always pair up with good cell combinations. They can cause heart disease, diabetes, and certain cancers. So we want to prevent this from happening in the first place.

The brain receptor mentioned above is called N-methyl-D-aspartate (NMDA). Magnesium plays a protective role in the brain by protecting the NMDA and is now known as having a neuroprotective role in the brain.


Featured in: The Top 10 Brain Supplements

The use of magnesium is being studied for the prevention and treatment of migraine, chronic pain, epilepsy, Alzheimer’s, Parkinson’s, and even some kinds of stroke. The research is ongoing though, but hopefully, before long we’ll have more results. But the neuroinflammation and excitotoxicity is a feature of dementia and Alzheimer’s disease (AD). They have found that brains with AD did have depleted magnesium levels (Kirkland et al., 2018).

When the brain is working properly and has everything it needs, our moods are better, we think more clearly and anxiety and depression are reduced or cured. Magnesium helps to regulate all of that while protecting your most valuable resource, your brain.

Science of magnesium

What Else Does Magnesium Do?


One of the main things magnesium does for us is keeping us regular. It pulls water into the bowels and stimulates the colon. Without enough magnesium, we have constipation. Taking magnesium every day will make things run so much better.

It also regulates our sex hormones, estrogen and testosterone.

Another great function of magnesium is as a detox agent for the liver. It also helps you sleep, so taking it at night will give you a better night’s sleep which is important for your brain!

Related Article: The Gut and Brain Connection

Two essential functions of magnesium are with the heart and the brain. We already discussed the brain so let’s talk about the heart. Magnesium regulates the nervous system. It controls when nerves fire. Basically, it’s all to do with the electrolyte balance, the levels of calcium and also sodium and potassium ions on either side of a cell’s membrane (Sperlazza, 2018). Magnesium controls this delicate balance and steps in where it’s needed. If you are low on magnesium, there is nothing to stop nerves from over- or under-firing, which is what happens with arrhythmia and other heart and nerve problems.

In a book written by Dr. Sherry Rogers, “Is Your Cardiologist Killing You?” (2009), she states that most people don’t die of heart attacks; they die from magnesium deficiency. A pretty strong statement but imagine your heart after years of ill-functioning nerve controls.

Since magnesium also controls and helps us use calcium, it’s an extremely important macromineral for bone health and in treating osteoporosis.

How to Test for Magnesium


Most of us get the serum magnesium test, but it turns out that kind of test isn’t that accurate. It is recommended to get the intracellular magnesium method of testing for the amount of magnesium in your red blood cells. The reason for this is that more than half of the magnesium in our bodies is in bones and soft tissues and the true levels aren’t reflected accurately in the serum test.

Your RBC magnesium should be between 5.2 – 6.5 mg/dL.

You can order your intracellular magnesium lab test through this company in the US. It’s quite cost-effective. (I am not affiliated with this lab in any way).

It is highly recommended to test for Vitamin D at the same time since magnesium and Vitamin D depend on each other. Or you can just supplement Vitamin D. Most people don’t get enough Vitamin D without supplementation anyway and you would have to take 40,000 IU’s to reach toxic levels. It’s pretty hard to get too much.

Dr. Josh Axe video on Magnesium Deficiency Warnings:

Food Sources of Magnesium

  • Spinach
  • Broccoli
  • Artichokes
  • Almonds
  • Pumpkin Seeds
  • Avocado
  • Bananas
  • Cabbage
  • Asparagus
  • Dark chocolate
  • Spirulina
  • Salmon *** Also a good source of Omega-3 fatty acids which makes it a superfood

But remember, the plant sources aren’t as powerful as they used to be. But it sure couldn’t hurt.

salmon and asparagus good sources of magnesium

Salmon and asparagus are good sources of magnesium

What Causes Low Magnesium?

  • Little ingestion of natural spring water (good source of magnesium)
  • Soil depletion
  • Digestive disorders, diabetes, and other medical conditions
  • Alcohol consumption
  • Rx’s and over the counter meds
  • Stress – Stress kicks magnesium out of cells – chronic stress causes depletion

We can beat this! The cost of magnesium supplements is low.

Further, it’s so easy to get. Most people simply don’t know they need it. But now you do! Supplementing your diet with magnesium is one of the best things you can do for your health right now and have immediate results.

Forms of Magnesium


Sperlazza (2018) gives a great guide on the different forms of magnesium and what each is best used for.

However, any of these forms will give you great benefits. Here are the various forms for enhanced effects in specific areas you desire:

  • Magnesium Oxide – constipation
  • Magnesium l-Threonate – memory and brain 🙂
  • Magnesium Citrate – relaxation
  • Magnesium Chloride – topical ‘oil’ spray or liquid drops for people with low internal absorption rate or adrenal fatigue
  • Magnesium Sulfate (Epsom salts) – relax and soothe muscles. Not the most exceptional absorption, though.
  • Magnesium Glycinate – sleep
  • Magnesium Chelate – easily absorbed

How Much Should I Take?


It is recommended to take 600-800 mg per day, at night (according to the Bulletproof philosophy). Remember that it will rev up your bowels, so start with 300-400 mg per day and work yourself up to the 600-800mg per day dose, so you don’t end up with ‘oopsy pants’. This way you can get to your optimal dose as well. It might be lower than 600mg. If you get diarrhea, you should cut back.

You can take less than that with Chelated Magnesium since it’s more absorbable.

It will make you relaxed, so nighttime is the perfect time to take it. One of the benefits is great sleep, which helps your brain detox.

If you also take Bacopa Monnieiri, an herbal brain supplement, then take it with your Bacopa a few hours before bed.

Related Article: Bacopa Monnieri Benefits


Where We Are Now…

So we went over the side effects of low magnesium and the benefits of magnesium – helping the brain not go into neurotoxicity, helping the nerves regulate heartbeat and other nervous system functions, cure or prevent constipation, help for detoxifying the body and liver and help with getting to sleep and sleeping better. Even bone health and osteoporosis.

This Carlson Chelated Magnesium is highly recommended by Dr Sherry Rogers:

Click Here for Info

I hope you learned some new things about magnesium from this article or solidified what you already knew. Above all, you need to start taking magnesium if you aren’t already. Click the links above to shop for your preferred form of magnesium on Amazon. Thank you very much for visiting.

Please feel free to leave comments, questions, or your experience with magnesium in the comment section below. I’ll be sure to respond quickly. Thank you!


Kirkland, A., Sarlo, G., and Holton, K. (2018). The Role of Magnesium in Neurological Disorders. US National Library of Medicine, National Institutes of Health. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6024559/

Rogers, S. (2009). Book. Is Your Cardiologist Killing you?. Published by Prestige Publishing.

Sperlazza, C. (2018). How to choose the best magnesium supplement for your body. https://www.bulletproof.com/supplements/vitamins-minerals/best-magnesium-supplement/

Sperlazza, C. (2018). Magnesium Deficiency Signs and Symptoms & How To Fix It. https://www.bulletproof.com/supplements/vitamins-minerals/magnesium-deficiency-supplements-causes/

Get Updates!

Sign up for email notifications when there are new articles on MyWellBrain!