The Best Time to Take Magnesium for Anxiety, Sleep and Relaxation

Wondering whether to try taking magnesium to improve your sleep and help with anxiety problems?

Magnesium is an essential mineral in our body that's naturally present in several foods and is also available as a dietary supplement.

Magnesium is required to regulate hundreds of fundamental biochemical reactions in our bodies, from nerve and muscle function to our immune system.

Carol Haggans, a registered dietitian (RD) and nutrition scientist under contract to the U.S. National Institutes for Health (NIH) Office of Dietary Supplements, told Newsweek: "Getting enough magnesium is very important for overall health, including building and maintaining healthy bones and regulating blood pressure."

Some people are more likely to be magnesium deficient, including older adults and those with gastrointestinal diseases, type 2 diabetes or alcohol dependence, Haggans said.

An insomniac woman laying in a bed.
A woman unable to sleep, laying awake on her bed at night. A magnesium deficiency can lead to several health conditions, including insomnia. iStock/Getty Images Plus

But instead of immediately reaching for magnesium tablets, making sure you are consuming the daily recommended dietary allowance (RDA) for magnesium from food sources would be a good place to start for improving your sleep and anxiety levels, Roxana Ehsani (RoxanaEhsani.com), a registered dietitian nutritionist (RDN) and the national media spokesperson for the Academy of Nutrition and Dietetics, told Newsweek.

"However if for some reason you aren't consuming whole grains, nuts, seeds or dark leafy greens due to having a food allergy or intolerance," then "taking a magnesium supplement daily is okay," the RDN said.

But you should always consult with your physician before taking magnesium supplements, as certain medications may interfere with them, she warned (more on this and other risks associated with magnesium supplements later below).

Below experts explain the best time to take magnesium for sleep, anxiety and relaxation.

Types of Magnesium Supplements

There are many different forms of magnesium supplements on the market, with magnesium oxide, citrate and chloride being among the most common, said Haggans.

Magnesium citrate has the highest bioavailability, "meaning it is absorbed the best and fastest by the body," Ehsani explained.

Below are some common magnesium supplements available:

  • Magnesium sulfate
  • Magnesium aspartate
  • Magnesium lactate
  • Magnesium citrate
  • Magnesium glycinate
  • Magnesium L-threonate
  • Magnesium chloride
  • Magnesium oxide

Haggans said some dietary supplements contain only magnesium, while others contain magnesium along with other ingredients, such as calcium or vitamin D. Most multivitamins and mineral supplements also contain magnesium.

Dr. Stella Lucia Volpe, an RDN and certified exercise physiologist who is a fellow with the American College of Sports Medicine (ACSM), told Newsweek: "Remember that any mineral supplement must be bound ('chelated') to a substance (e.g., citrate or glycinate) to help maintain the stability of the mineral and help with absorption."

The true amount of a specific mineral in a supplement is described as "elemental." So in the case of magnesium, it would be listed as "elemental magnesium," explained Volpe.

A bottle of magnesium capsules.
A bottle of magnesium capsules. Those taking magnesium supplements should be careful to stick to the daily recommended amount.

Which Magnesium Is Best for Sleep and Anxiety?

Haggans said it's currently unclear whether magnesium supplements are helpful for sleep, anxiety or relaxation. For example, a recent review of studies published in April 2021 in BMC Complementary Medicine and Therapies journal concluded "there isn't enough evidence to recommend magnesium for insomnia in older adults," the nutrition scientist said.

The study noted, however, that "given that oral magnesium is very cheap and widely available, RCT [randomized control trials] evidence may support oral magnesium supplements (less than 1 gram quantities given up to three times a day) for insomnia symptoms."

Haggans explained that whether a person would benefit from a magnesium supplement "depends largely on how much they're already getting from the foods and beverages they consume."

Those with a magnesium deficiency may experience muscle contractions and cramps, along with other symptoms, which could disrupt their sleep, so "correcting the magnesium deficiency should help," according to Haggans.

But it's unclear whether a supplement would be helpful for someone who is already getting enough magnesium, she added.

Volpe agreed that studies about the effect of magnesium on sleep, anxiety and relaxation are limited. "Some research has shown that magnesium might help sleep some, but not significantly," she said.

For example, magnesium supplementation has been shown to increase sleep time by about 16 minutes. However, "those extra 16 minutes can be a lot for someone who is having trouble sleeping," the ACSM fellow noted.

It's unclear exactly which magnesium supplements are best for sleep and anxiety.

According to Volpe, some researchers in some small studies have reported that magnesium glycinate, aspartate, citrate, lactate and chloride are better absorbed than magnesium oxide and magnesium sulfate.

The better absorption of these magnesium supplements helps increase intake of the magnesium supplement, which may allow for better results in improving sleep and anxiety symptoms .

Magnesium supplements with poor bioavailability, such as magnesium oxide, are avoided for addressing sleep issues as they may produce a laxative effect, which isn't conducive to sleeping.

Ehsani highlighted that one small study from 2010, published at the website of the U.S. National Library of Medicine of the National Institutes of Health (NIH), found that 320 milligrams (mg) of magnesium citrate was associated with improved sleep in participants aged over 50.

According to the RDN, some other studies have found that people with low levels of magnesium may see an improvement in mood and reduced anxiety when they begin supplementation or consume more dietary sources of magnesium.

"Another small study found that people with depression and low serum magnesium levels found their depression symptoms lessened with supplementing with magnesium," Ehsani added.

An anxious man with hand on head.
A man looking anxious with his hand on his head. Some studies have suggested magnesium intake could potentially play a role in reducing anxiety. iStock / Getty Images Plus

How Much Magnesium to Take for Sleep Improvement

There's no specified amount of magnesium that's believed to be ideal for sleep improvement. Haggans said the recommended daily amount of magnesium is 310 to 320 mg for most women (while those who are pregnant need slightly more) and 400 to 420 mg per day for men. These amounts include all the magnesium you get from dietary supplements as well as food and beverages.

The nutrition scientist explained: "Magnesium found naturally in food and beverages does not have an upper limit. So men should still strive to consume a total of 400-420 mg of magnesium per day from food, beverages, and if needed, a supplement. Women should strive to consume 310-320 mg."

Volpe also warned "more is not better" when it comes to magnesium supplements. So individuals should not take a higher dose of magnesium than recommended.

"In addition, healthy sleeping habits, like going to bed the same time each evening and not using electronic devices in bed, are also important to help individuals sleep better," she said.

When to Take Magnesium for Sleep

Volpe said it is recommended to take the magnesium supplement about 30 minutes prior to bed for those taking magnesium to see if it helps them to sleep.

Ehsani said it's also recommended to take magnesium supplements with food, "so possibly with your last meal like dinner or evening snack."

A woman sleeping on a bed.
A woman sleeping on a bed. Some studies have show taking a magnesium supplement could potentially help with sleeping issues. iStock/Getty Images Plus

The Risks of Taking Magnesium Supplements

While too much magnesium from food sources does not pose a health risk in healthy individuals (since their kidneys eliminate excess amounts in the urine), high doses of magnesium supplements do come with potential health hazards.

Although magnesium supplements are "relatively safe" for those who are healthy, the recommended daily intake limits should be followed, Volpe warned. "Taking too much of any vitamin or mineral can lead to negative side effects" and "the risk of magnesium toxicity increases if a person has compromised kidney function."

Haggans also said: "Taking a magnesium supplement at recommended amounts is safe for healthy people." But consuming too much magnesium from dietary supplements or medications that contain magnesium, such as laxatives and antacids, can cause health problems, with some of the extreme cases including irregular heartbeat and cardiac arrest, she warned.

Taking high doses of magnesium can potentially lead to the following health conditions, according to Haggans, Volpe and Ehsani.

  • Low blood pressure
  • Nausea
  • Vomiting
  • Upset stomach
  • Stomach cramps
  • Gastrointestinal distress
  • Diarrhea
  • Flushing in the face
  • Inability to void urine
  • Depression
  • Muscle weakness
  • Difficulty breathing
  • An irregular heartbeat
  • Heart attack

There are several types of medications and supplements that may interact with magnesium supplements, such as ones listed below, according to the NIH Office of Dietary Supplements:

  • Bisphosphonates
  • Antibiotics
  • Diuretics
  • Prescription drugs used to ease symptoms of acid reflux or treat peptic ulcers
  • Very high doses of zinc supplements

A spokesperson for the U.S. Food and Drug Administration (FDA) told Newsweek that in general, individuals should always consult with a health care professional before using any dietary supplement. Your health care professional can advise whether it is safe for you to take a certain product and whether it's appropriate for your needs, the FDA spokesperson added.

When Will I Start Seeing Results?

Haggans said it's hard to know when a person will see the effect of taking magnesium supplements because "most magnesium in the body is inside cells or in bone, so assessing someone's magnesium 'status' (meaning whether they are getting enough) via things like blood tests is challenging.

"In addition, other factors may be involved. For example, calcium and vitamin D also affect bone health," she said.

Volpe also noted it's important to bear in mind that magnesium supplements aren't for everyone. "Some people may not respond at all to magnesium supplementation for sleep."

For those who do respond to it, how long it takes to see the effects varies widely. For some it may take a week or two, while others may see the effects sooner, she said.

A table spread of nuts, seeds, vegetables.
A table spread of nuts, seeds and leafy greens, which are great natural sources of magnesium. iStock/Getty Images Plus