Can too much vitamin D cause anxiety?

Can Too Much Vitamin D Cause Anxiety?

  • ​Have you been experiencing increased anxiety since you began supplementing with vitamin D?
  • ​Are you worried this might be due to vitamin D?

It could.

Vitamin D can increase your anxiety because of the way it influences both your magnesium and calcium metabolisms.

But you can make things right again.

In this article, you’ll learn what’s happening and how you can turn it around.

You’ll understand the steps you need to take so that vitamin D ends up reducing your anxiety instead of increasing it.


To achieve this, we’ll look at 3 key areas:

  • 1
    ​The role of in magnesium in promoting the health of your nervous system.
  • 2
    ​How vitamin D depletes your magnesium reserves and how you can counteract that.
  • 3
    ​Why Vitamin D actually helps you feel calmer as long as you make sure that your body has enough magnesium available.

In a Hurry?

​Click here to find a nice summary of the main points of this article at the end.

The role of in magnesium in promoting the health of your nervous system.

​​​“Anxiety disorders are the most common mental illness in the U.S., affecting 40 million adults in the United States age 18 and older, or 18.1% of the population every year.“ (1)

If you suffer from anxiety, you are not alone as it has been estimated that this problem affects 40 million people, just in the United States. (2)

Could magnesium help?

Magnesium deficiency has been known to cause anxiety. As a result, its supplementation has been carefully purposed as having the potential to help. (3)

Similarly, in 2013, when a group of Spanish researchers from the University of Navarra reviewed the studies evaluating the role of magnesium in depression they concluded:

Magnesium seems to be effective in the treatment of depression but data are scarce and incongruous. Disturbance in magnesium metabolism might be related to depression. Oral magnesium supplementation may prevent depression and might be used as an adjunctive therapy. However, more interventional and prospective studies are needed in order to further evaluate the benefits of magnesium intake and supplementation for depression. (Emphasis added) (4)

Did you notice the careful wording?

This is intentional, and you’ll find it in most research papers.

For example, in Dietary magnesium and calcium intake and risk of depression in the general population: A meta-analysis, (5) a group of researchers got together to make an analysis of the many scientific studies examining the relationship between these two minerals and depression.

What is a meta-analysis?

  • ​The English word “meta” comes from the Greek word “μετά” which means “after” or "beyond."
  • ​When researchers get together to perform a meta-analysis this means they are going to review the available papers, looking beyond individual clinical studies, checking for any patterns that may stand-out.
  • For example, there might be 10 studies demonstrating an outcome but 2 studies showing no results whatsoever. Researchers will try to understand why this happened and describe their own conclusions in their meta-analysis.

​What did they find in this meta-analysis?

“For dose-response analysis, evidence of a nonlinear relationship was found between dietary [Magnesium] intake and risk of depression, and the largest risk reductions were observed for 320 mg/day.”

Or, in other words, it is as if they said:

​“Magnesium intake lowers your chances of getting depression. How much should you take?

At least 320 mg per day”.

Yet, they can’t actually say it like this. Why?

Because they can’t know for sure.

They can only report what they have observed.

And what they saw, was that in some cases, under some circumstances, magnesium helps.

That’s why, in the end, they state:

“This meta-analysis indicated that moderate [magnesium] intake may be inversely associated with the risk of depression, which still needs to be confirmed by larger prospective cohort studies.”

Or, in other words, it is as if they were saying:

“Yeah, it really seems magnesium helps you avoid depression, but, who knows, we might be wrong. Someone needs to do a much bigger study. That’s the only way to know for sure.”

However, what researchers said it’s enough for you to make an educated guess about the role of magnesium in your nervous system health.

Educated guess

​​If your levels of magnesium were to drop and you got magnesium deficient, you’d be likely to feel more anxious than usual.

If your levels of magnesium were to drop and you got magnesium deficient, you’d be likely to feel more anxious than usual.

Moreover, as a study from 2001 pointed out, magnesium deficiency its associated with a host of other disorders, including migraine, premenstrual syndrome, cramps, hypertension, and other cardiovascular problems. (6)

Any of these would impact your mood and leave you unease.

Then, even if you don’t agree that supplementing with magnesium will help you feel calmer, I hope you can see how a magnesium deficiency would most likely trigger anxiety.

Therefore, if higher doses of vitamin D can deplete your magnesium reserves it would be logical that too much vitamin D could also make you anxious.

Well, can they?

Let’s examine this issue further.

How vitamin D depletes your magnesium reserves and how you can counteract that

Magnesium is involved in at least 300 (7) chemical reactions inside your body. Some of these involve vitamin D. (8)

For example, vitamin D needs to be transformed, transported and activated. All these steps require magnesium and this will deplete your reserves.

Because of this, if you have been supplementing with vitamin D without also nourishing your body with sufficient magnesium, you may end up deficient.

Worse yet, vitamin D can cause your calcium blood levels to rise.

This is especially true if you are undergoing any form of high-dose vitamin D therapy.

how too much vitamin d can make you feel anxious

How does vitamin D raise your calcium levels?

First, vitamin D stimulates your intestine to absorb more calcium from foods than usual.

This means that, when you are taking vitamin D, your body will work much harder to extract any calcium it can from what you eat and drink. That’s one of the reasons why people on the Coimbra Protocol are required to follow a low-calcium diet.

Secondly, too much vitamin D stimulates your bones to release more calcium into the blood than they normally would.

Could higher calcium have a negative influence on your nervous system?

Yes, because of how calcium interacts with magnesium.

Higher levels of calcium, a condition called hypercalcemia, can cause your magnesium levels to drop to the point of hypomagnesemia. (9)

the meaning of hypomagnesemia

But there’s more.

When calcium levels rise in your blood, your kidneys become responsible for restoring the correct values.

They do this by excreting any excessive amount of calcium through the urine.

This creates two potential problems:

  • ​Getting high amounts of calcium flowing through your kidneys all the time increases the risk of kidney stones
  • ​If the kidneys aren't working in perfect condition, excessive urination may lead to the excretion of other vital minerals together with the calcium, including potassium and magnesium.

This can further harm your nervous system.

Don’t be scared though.

This would only happen if you were supplementing with high doses of vitamin D for too long and without caring about safety.

The meaning of hypercalcemia

How can you prevent vitamin D supplements from making you anxious?

First, you need to make sure you are getting the right vitamin D dosage for your organism.

How much is that?

Unless you have an autoimmune condition or are otherwise known to be deficient in vitamin D, this dosage would be of about 10,000 IU per day.

If you are thinking about getting pregnant, expecting or lactating check the correct vitamin D for a pregnant woman.

Next, you must make sure you are not magnesium-deficient.

If you are, the extra demands vitamin D puts on your magnesium supplies could end up depleting them. Then, you could begin feeling the symptoms of magnesium deficiency, including anxiety.

That’s why it’s recommended that you supplement with magnesium.

If you are supplementing with vitamin D, you should be supplementing with magnesium

Also, if you are on a high-dose vitamin D protocol, like the Coimbra Protocol, you must make sure you are following the safety guidelines. These include a dairy-free low-calcium diet along with increased fluid intake and regular blood and urine tests. These are to ensure your calcium levels remain within the normal range.

When you take these recommendations into account you might be surprised with the results.

Instead of keeping you awake at night, vitamin D might become yet another ally in helping you relieve your symptoms of anxiety and even depression.


Why Vitamin D actually helps you feel calmer as long as you make sure that your body has enough magnesium available.

As it turns out, vitamin D helps your body regulate the chemicals involved in anxiety and depression, like adrenaline, serotonin, and even dopamine. (10)

In Vitamin D and Depression: A Systematic Review and Meta-Analysis Comparing Studies with and Without Biological Flaws, a group of researchers got together to make an analysis of the many scientific studies examining the relationship between vitamin D and depression.

What was their conclusion?

When these researchers focused on properly conducted studies, their conclusion was:

"Meta-analysis of studies without biological flaws demonstrates that improving Vitamin D levels improves depression (...)" and:

"the effect size of Vitamin D demonstrated in our meta-analysis may be comparable with that of anti-depressant medication. (...) Should these results be verified by future research, these findings may have important clinical and public health implications." (Emphasis added) (11)

​​"Improving Vitamin D levels improves depression."

What dose of vitamin D did they use?

By analyzing the various studies, these researchers found out that the daily doses use ranged between 400 IU and 18,400 IU.

vitamin D used in depression research

In fact, vitamin D besides being potentially as effective at treating depression as some antidepressants, it can even enhance the antidepressant effect of fluoxetine. (12, 13)

It's as if, without enough vitamin D, your body would get confused, finding it troublesome to properly regulate the production of these hormones and neurotransmitters.

This means that, as long as you provide your body with enough magnesium, vitamin D will help your nervous system work better.

​The Main Idea

​As long as you provide your body with enough magnesium, vitamin D will help your nervous system work better.

Even if you are undergoing treatment with a high-dose protocol, you can still reap the beneficial effects of vitamin D over your nervous system as long as you follow the safety guidelines – including a low-calcium diet – and take the main vitamin D co-factors, giving special attention to magnesium.


​can vitamin d supplements cause anxiety?

  • ​After getting inside your body, vitamin D will need to be transformed, transported and activated. All these steps require magnesium and will deplete your reserves of this mineral.
  • ​In the long term, taking too much vitamin D without also supplementing with magnesium can lower your magnesium levels and this will have a negative effect over your nervous system.
  • Because of how it promotes calcium absorption from food and calcium release from the bones into the blood, long-term high-dose vitamin D supplementation can cause your calcium blood levels to rise too much. This, in turn, will further increase your magnesium needs and negatively affect your nervous system.
  • This is especially true if you are following a high-dose vitamin D protocol, like the Coimbra Protocol.
  • Vitamin D has a great potential to help you deal with stress and contribute to a less anxious life. But, if you want to reap this benefit you need to make sure you keep supplementing with magnesium while also making sure your calcium levels are kept within their normal range.
Tiago Henriques

With more than 10 years of experience as a Public Speaker, Tiago Henriques has done hundreds of public talks. He was born in 1987, in Portugal, and is the Author of 3 books — and counting — and the creator and editor of the Portuguese Science Project, "Ciência Desenhada," where complicated science is explained in a simple way, using whiteboard animation techniques.Tiago developed his own practical and down-to-earth teaching method inspired by his experiences with the Portuguese Deaf Community and their use of highly visual, descriptive and easy-to-understand language.

  • Avatar Mo says:

    How very interesting. My anxiety has been going through the roof on Vit D supplements. So, now I know to take more magnesium.

    However, I found that magnesium raises my anxiety also! Even if I take it in the morning, it keeps me awake at night! Why does magnesium not relax me?

    • Hi Mo,

      At its chemical core, anxiety is mainly caused by a drop in serotonin.

      Both vitamin D and magnesium help in the formation of serotonin, but there’s a catch: you’ve got to have enough tryptophan available.

      Tryptophan being the building block your body requires to sculpt the serotonin molecule.

      In my own personal experience, about three 00-size capsules filled with l-tryptophan powder, are enough to take away the anxiety within the hour.

      If you are seriously suffering from anxiety you may want to try adding 1 gram of l-theanine to the tryptophan.

      However, make sure you don’t drive or operate heavy machinery afterwards since you might feel too relaxed and sleepy.

      Of course, you can — and probably should ☺️ — start with a much lower dosage.

      In my own case, when I have to deal with extreme anxiety I take the 3 home-made tryptophan caps + 2 l-theanine 500mg capsules twice a day.

      5-htp is supposed to help your body synthesize serotonin too. However, in my own personal experience, 5-htp supplements didn’t make a single dent on my anxiety levels, whereas the effect of l-tryptophan is very pronounced, especially when combined with l-theanine.

      Ps.: this is my own personal experience. Please be sure to consult with a doctor and research any possible side effects that either tryptophan or l-theanine could have in your particular case, specially if you are taking any antidepressants or anxiolytics. Also, make sure you start with lower dosages.

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