Snooze University

Why Does Magnesium Citrate Cause Insomnia?

by Dale Cudmore | Updated: May 16, 2021

Magnesium is an important mineral for sleep.

For people who are struggling to get enough in their diets, supplements are a good option. Magnesium citrate is among the most popular forms of magnesium supplements (magnesium glycinate is a higher quality alternative).

When everything goes as expected, magnesium supplements improve sleep. A 2021 review found (1):

...sleep onset latency time was 17.36 min less after magnesium supplementation compared to placebo

In plain English, subjects with insomnia who take magnesium supplements typically fall asleep just over 17 minutes faster.

However, some people find that magnesium citrate makes their sleep worse. While no comprehensive studies have looked at this topic, there are 4 main possible reasons for this that we’ll go over here.

Possible Negative Reactions to Magnesium Citrate

Different forms of magnesium can have different effects on certain individuals.

Magnesium citrate has a similar bioavailability to magnesium glycinate, which is about 4 times higher than magnesium oxide (the cheapest kind) (2). So overall the citrate version is relatively high quality.

However, despite this high bioavailability, magnesium citrate is known to cause stomach issues. It’s sometimes used medicinally as a laxative prior to surgery (3).

The effect will depend on the dosage taken, and individual sensitivity. But other related symptoms like gas, nausea, and abdominal cramps are common.

Taking too much magnesium citrate, especially for an extended time period can cause more serious side effects (weakness, mood changes, irregular heartbeat, and more).

SummaryMagnesium citrate absorbs well, but is known to have a laxative effect when taken in significant amounts. Any intestinal discomfort can cause sleep issues.

Low Quality Magnesium Citrate

In many countries, especially the United States, supplements aren’t as strictly regulated as you might think.

Low quality brands import low-cost and low quality products from overseas and put a nice label on it.

For example, melatonin is the most popular natural sleep aid supplement. A study found that (4):

Melatonin content did not meet the label within a 10% margin of the label claim in more than 71% of supplements and an additional 26% were found to contain serotonin.

It’s reasonable to assume this sort of issue exists in other supplements like magnesium as well.

Not only may your magnesium supplement not contain as much magnesium as it should, it may actually contain other substances that cause sleep issues.

SummaryMany supplements have poor quality control and the nutritional claims on labels do not come close to matching the actual product. Look for third-party audited supplements at the very least to improve the odds that the product actually contains what it’s supposed to.

Too Much Magnesium (Side Effects)

We touched on it a bit earlier, but having too much magnesium is likely to cause a variety of digestive issues, and can cause mood issues (which could affect sleep).

The NIH states that the tolerable upper intake for adults is 350 mg of magnesium per day (5):

A typical magnesium citrate has around 250 mg per capsule. It’s really easy to go over the maximum amount someone should be having, especially for smaller people.

You have to keep in mind that even if someone isn’t getting enough magnesium from food, they are still getting some.

Now typically the symptoms are going to be really obvious, but in the rare case of mood changes alone, too much magnesium could cause depression and insomnia.

SummaryAside from obvious safety reasons, it’s possible that ingesting too much magnesium over time could cause insomnia from both obvious and non-obvious symptoms.

Magnesium Citrate Can Interact With Other Substances

There’s a reason that pretty every supplement advertisement tells you to consult with your doctor before taking it.

Magnesium supplements can interact with certain medications that someone might be taking and cause a wide variety of side effects.

The most studied negative interactions with magnesium supplements are (5):

  • Bisphosphonates
  • Antibiotics
  • Diuretics
  • Proton pump inhibitors

But if you’re taking any other over the counter supplements, it’s possible that they could have unexpected interactions.

SummarySymptoms from medication interactions can vary widely, but symptoms like restlessness and disruption of hormone regulation are types of symptoms that could cause insomnia.

Summary: Effect of Magnesium Citrate on Sleep

For people with a magnesium deficiency, taking a magnesium supplement like magnesium citrate will improve sleep.

However, there are anecdotal reports of magnesium citrate actually causing insomnia. The most likely reasons that we looked at are taking too much, having a low quality supplement, or an unexpected interaction.

If the sleep issues or insomnia are new and serious, consulting a doctor is a good idea.

Other potential solutions include taking the supplement early on in the day, taking less of it (or every other day), and trying a different form of magnesium.


  1. Oral magnesium supplementation for insomnia in older adults: a Systematic Review & Meta-Analysis
  2. Bioavailability and pharmacokinetics of magnesium after administration of magnesium salts to humans
  3. Magnesium Citrate Oral
  4. Melatonin Natural Health Products and Supplements: Presence of Serotonin and Significant Variability of Melatonin Content
  5. Magnesium: Fact Sheet

Medical Disclaimer: The information on is not intended to be a substitute for physician or other qualified care. We simply aim to inform people struggling with sleep issues about the nature of their condition and/or prescribed treatment.

About the authorDale is the founder of Snooze University and a sleep researcher. I overcame my sleep issues and now I'd like to help you do the same by summarizing the latest sleep studies for you.