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Why Does Magnesium Glycinate Give Me Insomnia? 4 Reasons

by Dale Cudmore | Updated: May 18, 2023

Magnesium is arguably the most important mineral when it comes to sleep (and a bunch of other things). It’s involved in functions like muscle contraction and relaxation.

In most people with insomnia, magnesium helps improve sleep quality (1, 2).

However, there are always exceptions.

While magnesium glycinate is typically one of the best forms of magnesium for sleep, I’ve heard of many people starting to take a magnesium supplement and then report insomnia symptoms.

While this hasn’t been specifically studied, we can put together a few research-based “guesses” as to why this might happen.

1. An Individual Reaction to Magnesium Glycinate

Magnesium supplements can come in many forms.

Magnesium oxide is the cheapest and least absorbable.

Every other form of magnesium (e.g. aspartate, glycinate, citrate, etc.) are about 4 times as bioavailable (3, 4, 5). In addition, magnesium can be chelated to improve bioavailability further.

The most common magnesium supplements are (roughly from lowest to highest quality):

  • Magnesium oxide
  • Magnesium citrate
  • Magnesium malate
  • Magnesium threonate
  • Magnesium glycinate

Some people experience side effects with one form of magnesium, but not another.

While glycinate is one of the highest quality forms, some people find that magnesium glycinate keeps them awake at night, but other types do not.

SummaryIf magnesium glycinate causes sleep issues, switching to a different type of magnesium supplement can often work. It’s also recommended to try taking supplements in the morning when concerned about sleep trouble.

Reactions to Glycine

Why might glycinate cause a reaction?

Magnesium glycinate is a magnesium salt of glycine, which is an amino acid and neurotransmitter.

Glycine can both act as a stimulant or depressant role in the brain. It improves sleep quality in most, but there are going to be some people who experience more of a stimulating reaction to it than others (6, 7).

2. Some Magnesium Supplements Are Low Quality

Most people don’t realize how unregulated the supplement industry is (in most countries, including the United States).

Many products slap a shiny label on a cheap product they import from a low-cost manufacturer, which is often low quality. And when it comes to platforms like Amazon, it’s really easy to buy fake 5 star reviews.

While there are no studies on magnesium supplements in particular, there are some on a related sleep supplement - melatonin. One study found that (8):

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.

Most other types of supplements are not any better.

When you’re buying a magnesium supplement, it may have more or less magnesium than promised on the label, or it may have other ingredients that it shouldn’t.

Stick to brands that you trust are sourcing quality products.

If you need a recommendation, Future Kind has a great plant-based Magnesium glycinate supplement that's chelated to improve absorption.

SummaryMagnesium glycinate may not necessarily be the cause of insomnia issues. Instead, there could easily be other ingredients in a particular brand that could cause problems. While it’s no guarantee, more expensive, reputable brands, with third party testing are the best signal of a high quality supplement.

3. Too Much Magnesium Can Lead to Side Effects

Just as low magnesium levels can lead to health problems like insomnia, having too much magnesium is also a problem.

The tolerable upper intake for adults is 350 mg of magnesium per day according to the NIH (9):

Supplements typically have up to a few hundred grams of elemental magnesium, and considering that some have more than is claimed on the label, it’s easy to see how you might accidentally go over the upper limit.

People who are on the small side need to be even more careful.

The best way to check this is to get a blood test to measure your magnesium levels and see how high they are.

Consequences of Too Much Magnesium

It’s extremely difficult to get too much magnesium from just food, but when you add supplements on top of it, particularly ones that absorb well (e.g. magnesium glycinate), it’s very possible.

Too much magnesium makes the kidneys work harder, and can also cause (3, 10,11):

  • Diarrhea (most common)
  • Cramping
  • Nausea
  • Depression
  • Lethargy
  • Irregular heartbeat

Any of these can indirectly cause sleep issues and even insomnia in some.

In really high amounts, magnesium toxicity can be fatal.

SummaryMagnesium is an over the counter supplements that really should be taken with doctor supervision. It’s easy to consume too much and suffer health issues other than just sleep trouble.

4. Magnesium Glycinate Can Interact With Other Substances

Finally, and this goes for almost any supplement, magnesium glycinate can interact with anything else you might be taking.

The most known interactions of magnesium supplements are with (9):

  • Bisphosphonates
  • Antibiotics
  • Diuretics
  • Proton pump inhibitors

Those are just the ones with significant research behind them.

Any other supplements could also have a complex interaction that leads to a side effect that causes insomnia.

SummaryOne of the main reasons that supplements always come with a warning to only take with doctor supervision (even though they’re sold over the counter, which is silly), is because they can interact with each other and cause unexpected side effects.

Summary: Magnesium Glycinate and Insomnia

For most people, magnesium glycinate improves sleep quality. There’s a lot of research behind that.

However, not everyone reacts the same, and research looks at the average, not the outliers.

The most likely reasons that magnesium glycinate can keep you awake are:

  • A reaction to this specific form of magnesium
  • A low quality supplement with a different amount of magnesium in it, or other ingredients
  • Consuming too much magnesium
  • Interactions with other supplements

The best course of action for anyone having sleep issues while taking a magnesium glycinate supplement is to see a doctor, and likely get a blood test to check magnesium levels.

If your levels are low, your doctor will likely recommend taking a different brand or form of magnesium, and carefully monitoring the results.


  1. The Effect of Melatonin, Magnesium, and Zinc on Primary Insomnia in Long‐Term Care Facility Residents in Italy: A Double‐Blind, Placebo‐Controlled Clinical Trial
  2. The Effects of Magnesium – Melatonin - Vit B Complex Supplementation in Treatment of Insomnia
  3. Bioavailability and pharmacokinetics of magnesium after administration of magnesium salts to humans
  4. Bioavailability of US commercial magnesium preparations
  5. Magnesium bioavailability from magnesium citrate and magnesium oxide
  6. New Therapeutic Strategy for Amino Acid Medicine: Glycine Improves the Quality of Sleep
  7. The Effects of Glycine on Subjective Daytime Performance in Partially Sleep-Restricted Healthy Volunteers
  8. Melatonin Natural Health Products and Supplements: Presence of Serotonin and Significant Variability of Melatonin Content
  9. Magnesium: Fact Sheet
  10. DRI Dietary Reference Intakes For Calcium, Phosphorus, Magnesium, Vitamin D, and Fluoride
  11. Magnesium metabolism in health and disease

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.