Various studies have found that magnesium may have a range of benefits, including helping to improve sleep quality. Magnesium is a mineral naturally present in many foods and available as a supplement.

Although more research is necessary to determine how magnesium affects sleep quality, various studies have found the mineral positively impacts sleep.

Researchers believe magnesium may promote better sleep in various ways, such as reducing the stress hormone cortisol, increasing a sleep-promoting hormone called melatonin, and helping to regulate neurotransmitters for the central nervous system (CNS).

This article looks at how magnesium may affect sleep, other benefits, how to supplement with magnesium, and foods that contain the mineral. It also examines the risks of excessive magnesium intake and compares it with melatonin.

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More research is necessary to determine how magnesium affects sleep. Researchers believe the mineral may promote better sleep in the following ways:

  • Regulating GABA in the CNS: Gamma-aminobutyric acid (GABA) is a neurotransmitter in the brain that calms the nervous system by stopping certain signals from transmitting. Magnesium may play a role in regulating GABA, which could help promote calm and act as a sedative, to promote sleep.
  • Relaxing muscles: Magnesium may also inhibit another neurotransmitter, called the N-methyl-D-aspartate receptor, which could promote muscle relaxation. This could help improve general relaxation and sleep.
  • Promoting melatonin: Studies have found that people deficient in magnesium also have decreased melatonin, a hormone that maintains the circadian rhythm. The circadian rhythm causes changes in the body according to the day-night cycle, such as feelings of sleepiness and wakefulness.
  • Decreasing cortisol: Cortisol is a stress hormone and contributes to functions such as the fight or flight response. A decrease in cortisol could promote calm and help improve sleep.

Magnesium deficiency can increase a person’s risk of illness. Magnesium may be beneficial in the following ways:

  • Lowering the risk of type 2 diabetes: People who eat a diet rich in magnesium may be at significantly lower risk of type 2 diabetes. More research is necessary to determine whether magnesium supplements are effective at improving glycemic control in people with diabetes, however.
  • Lowering blood pressure: A diet rich in magnesium may lower blood pressure, which could be helpful for people with hypertension. An older study found that magnesium supplements may lower blood pressure, but only to a small extent.
  • Reducing migraine headache symptoms: People deficient in magnesium may experience factors promoting migraine headaches. One study suggests that a person may prevent migraine headaches by taking 300 mg of magnesium twice daily, alone or with medication. However, more research is necessary to determine the efficacy of magnesium as a preventive method or treatment for migraine. A person should discuss taking this dosage of magnesium with a doctor, as it may exceed the daily tolerable upper limit of supplemental magnesium. This could result in side effects.
  • Reducing the risk of osteoporosis: Magnesium may improve bone density and affect concentrations of vitamin D and parathyroid hormone, which play a role in bone health. Eating a magnesium-rich diet or taking magnesium supplements may help decrease osteoporosis bone loss.

Read about why we need magnesium.

Tolerable levels of magnesium supplements are lower than the recommended daily intake allowance. This is because a person may ingest magnesium in their food, medications, beverages, and supplemental form.

Magnesium supplements should not exceed the following daily dosages, in milligrams (mg), for the following age groups:

  • Birth–12 months: Researchers have not established safe intake levels of magnesium supplements for this age group, and a person should not allow infants to consume them.
  • 1–3 years: 65mg
  • 4–8 years: 110mg
  • 9–18 years: 350mg
  • 19 years and older: 350mg

Magnesium is present in a wide variety of animal and plant foods and beverages. Manufacturers also add magnesium to some breakfast cereals and other foods.

Food sources of magnesium include:

Learn more about foods high in magnesium.

High doses of magnesium from supplements or medications may cause health problems. These can include:

Magnesium supplements may also negatively interact with certain medications, including:

Magnesium and melatonin promote sleep quality in different ways. Magnesium may help to promote relaxation and stress reduction to improve sleep. Melatonin can help to regulate the circadian rhythm, and supplemental melatonin may help improve sleep in people with a disrupted circadian rhythm.

Research suggests that supplementing with magnesium, melatonin, and B vitamins may be effective in treating insomnia.

Read about home remedies for insomnia.

A diet rich in magnesium and the use of magnesium supplements may help promote better sleep.

Research has found that magnesium plays a role in improved sleep, but researchers are unsure of the exact mechanisms involved. Experts suggest magnesium may help with relaxation by interacting with certain neurotransmitters, decreasing cortisol levels, and increasing melatonin.

Excessive magnesium intake may cause side effects and could lead to health complications. The mineral may also interact with certain medications.