There are two huge mistakes that are often made with magnesium, and I see it all the time at the clinic. So instead of making those mistakes, let’s arm you with the knowledge to avoid them.
Plus, we’ll go through common questions about dose and forms of magnesium.
Table of Contents
- Magnesium’s Role in the Body
- Mistake #1: Not Getting Enough
- Magnesium and Health Conditions
- Mistake #2: How We Assess Magnesium
- How to Reach Your Recommended Magnesium Intake
- Choosing the Right Magnesium Supplement
- Final Thoughts
- References
Magnesium’s Role in the Body
Magnesium is an essential mineral required for more than 300 enzyme systems in the body. It’s involved in protein synthesis, muscle and nerve function, blood glucose control, and blood pressure regulation.
It also contributes to bone development, DNA synthesis, and the production of the antioxidant glutathione. Magnesium plays a crucial role in the active transport of calcium and potassium ions across cell membranes. And this is vital for nerve impulse conduction, muscle contraction, and maintaining a normal heart rhythm.
Mistake #1: Not Getting Enough
Yet despite magnesium’s importance, the evidence suggests many of us aren’t getting enough.
According to a recent estimate, 60% of adults do not get enough to hit the average dietary intake level. And 45% of the U.S. population is magnesium deficient [1].
And it isn’t super easy to find out if our magnesium levels are low, which we’ll return to in a minute.
Magnesium and Health Conditions
Why worry, especially because having magnesium levels low enough to cause obvious symptoms is relatively rare [2]?
The reason is that we have a lot of data linking low magnesium levels to serious health problems.
One of them is heart disease.
There was an observational study of 14,232 people over 12 years. It showed that higher magnesium intakes were associated with an almost 40% reduction in the risk of sudden death from heart problems [3].
Then a 2013 study involving over 300,000 people showed that higher magnesium levels were associated with a 30% lower risk of heart disease [4].
A separate study published in the Journal of the American Heart Association in 2016 showed that low magnesium levels are associated with a 36% higher risk of death compared to high levels [5].
And it’s not just heart disease. A 2012 study involving over 240,000 people showed that higher magnesium intakes are associated with a lower risk of strokes [6].
There are also strong associations between magnesium and metabolic syndrome markers like blood pressure, cholesterol, blood sugar, and insulin sensitivity.
For example, a 2011 study involving over 500,000 people showed that higher magnesium intakes are associated with a 22% reduction in the risk of developing type 2 diabetes [7].
The list goes on. Low magnesium intake is associated with dementia, poor hearing, Parkinson’s disease, depression, anxiety, and more.
But here’s the key thing to notice: most of the data we have about magnesium comes from observational studies. These show associations but not causation.
Take the example of magnesium and type 2 diabetes. A higher intake might lower risk. Or it could be that people who eat more magnesium also eat better overall or exercise more. So we can’t know for sure unless we look at controlled trials.
This is the first mistake: people are often led astray about the magnitude of magnesium’s impact. It’s easy to cherry-pick an observational stat to justify taking a supplement without addressing why you might be deficient in the first place.
Now, let’s turn to randomized controlled trials.
One study looked at 46 elderly patients with insomnia. Half took magnesium daily for 8 weeks, the other half took a placebo. Magnesium increased sleep time and reduced how long it took to fall asleep [8].
Blood samples showed that magnesium supplements increased melatonin levels and reduced cortisol levels—both crucial for better sleep.
A 2021 meta-analysis found that magnesium supplementation reduced the time it takes to fall asleep by about 17 minutes in older adults with poor sleep [9].
And a more recent meta-analysis showed that five out of eight sleep studies reported improvements with magnesium [10].
So while we need more clinical data to prove causation in many areas, we do know this: magnesium is essential, many of us aren’t getting enough, and supplementing can help—particularly with sleep.
Mistake #2: How We Assess Magnesium
Given how important magnesium is, it’s crucial to make sure we’re getting enough. But how?
The most common method is a blood test. But here’s the problem: only about 1% of the body’s magnesium is in the blood, and these levels are tightly controlled [11].
This means you can have normal blood magnesium but still be deficient overall [12].
A magnesium blood test is useful for detecting rapid changes, but not for assessing total body stores [13]. Saliva and urine tests exist, but none are considered truly reliable.
So the second mistake is thinking a normal blood test means you’re fine. I see this all the time at the clinic.
Instead of over-relying on tests, I advise my patients to make sure they’re getting adequate intake. If you’re reaching the recommended daily intake (RDA), your levels will generally be fine.
How to Reach Your Recommended Magnesium Intake
How do we do that? Not by just throwing supplements at the problem.
The RDA of magnesium is 420 mg for men and 320 mg for women.
Many of us fall short because we eat too many refined, processed foods. Magnesium gets stripped out. And instead of improving our diets, we reach for a pill.
The first step should be improving your diet.
Magnesium-rich foods include green leafy vegetables like spinach, legumes, nuts, seeds, and whole grains. Foods with dietary fiber generally contain magnesium. Meat has some, but not as much as plant-based sources.
Still, even with a good diet, it can be hard to hit the RDA. That’s because the mineral content in crops has declined over the decades [14].
That’s where a low-dose supplement can help. As the name suggests, it should supplement a healthy diet—not replace it.
That’s why I include 126 mg of magnesium in my Sleep supplement and in MicroVitamin. That’s about 30% of the RDA.
As we saw earlier, magnesium is linked to better sleep. And this amount helps me hit my daily goal.
Of course, just because I take something doesn’t mean you have to. But this leads us to a common question: what form of magnesium is best?
Choosing the Right Magnesium Supplement
First, beware of a common trick on supplement labels.
Magnesium oxide is a popular form because it’s cheap and high in elemental magnesium (60%). But many supplements list 400 mg of magnesium oxide, and people assume they’re getting 400 mg of elemental magnesium. They’re not. They’re getting only about 240 mg.
Magnesium oxide is also poorly absorbed.
Magnesium citrate is better absorbed and also cheap, but it only contains 11% elemental magnesium. So to get 126 mg of elemental magnesium, you’d need over 1,100 mg of magnesium citrate.
It also has a laxative effect, which may be helpful for some.
Magnesium-L-threonate is a newer, trendy form. Animal studies are promising, but human results are mixed.
One small, manufacturer-funded study showed a small improvement in one cognitive task, but no other benefits [15].
Another study in people with dementia showed no meaningful improvement [16].
So I’m not convinced it offers additional benefits—especially given its high cost.
Instead, I favor magnesium glycinate and magnesium taurate. These are bound to amino acids, are well absorbed, and have added benefits.
Glycine has been shown to improve sleep, which is why it’s in my Sleep supplement. Taurine has heart health benefits, and that’s why I include magnesium taurate in MicroVitamin.
Final Thoughts
Magnesium is just one of many nutrients we’re commonly deficient in. And there’s another that has a surprisingly strong link to heart health—backed by robust clinical data.
If you’re curious about the #1 nutrient deficiency linked to high blood pressure, watch the next article/video for more.
References
1. https://pmc.ncbi.nlm.nih.gov/articles/PMC6163803/
2. https://ods.od.nih.gov/factsheets/Magnesium-HealthProfessional/
3. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2939007/
4. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3683817/
5. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4859391/
6. https://pubmed.ncbi.nlm.nih.gov/22205313/
7. https://pubmed.ncbi.nlm.nih.gov/21868780/
8. https://pmc.ncbi.nlm.nih.gov/articles/PMC3703169/
9. https://bmccomplementmedtherapies.biomedcentral.com/articles/10.1186/s12906-021-03297-z
10. https://pubmed.ncbi.nlm.nih.gov/38817505/
11. https://academic.oup.com/ckj/article/5/Suppl_1/i3/447534
12. https://www.tandfonline.com/doi/full/10.1080/09637486.2021.1981831
