Magnesium Dosage: How Much Should You Take per Day?

Recommended daily amounts

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Magnesium is essential for maintaining proper health.

However, low magnesium intake is relatively common.

It’s primarily found in people who follow a typical Western diet, which contains processed foods and refined grains and can lack foods like leafy green vegetables and legumes, which provide magnesium and other important nutrients (3, 4).

The table below shows the recommended daily allowance (RDA) or adequate intake (AI) of magnesium for adults, infants, and children (2).

For pregnant people 18 or older, the requirements are increased to 350–360 mg per day (2).

Certain diseases and conditions are associated with magnesium deficiency, including high blood pressure, type 2 diabetes, and alcohol use disorder (5, 6, 7).

Taking a magnesium supplement may help increase magnesium levels in those who have a higher risk of deficiency or don’t consume enough through their diet.

Summary

The RDA for magnesium for adults is 310–420 mg, depending on age and sex.

Types of magnesium supplements

Many forms of magnesium supplements are available.

The most important thing to consider before deciding on a supplement is its absorption rate, or how well the supplement is absorbed by your body.

Here are brief descriptions of the most common magnesium supplements.

Magnesium gluconate

Magnesium gluconate comes from the magnesium salt of gluconic acid. In one older animal study, it was shown to have the highest absorption rate among other types of magnesium supplements (8).

Magnesium oxide

Magnesium oxide has the highest amount of elemental, or actual, magnesium per weight. However, it’s poorly absorbed. Studies have found that magnesium oxide is essentially insoluble in water, making absorption rates low (9).

Magnesium citrate

In magnesium citrate, magnesium in salt form is combined with citric acid. Magnesium citrate is absorbed relatively well by the body and has high solubility in water, meaning it mixes well with liquid (9, 10).

Magnesium citrate is found in pill form and commonly used as a saline laxative before a colonoscopy or major surgery.

Magnesium chloride

Like magnesium gluconate and citrate, magnesium chloride has been observed to be well absorbed by the body (2).

It’s also available as an oil that can be applied topically, but further studies are needed to fully understand how well magnesium in this form is absorbed through the skin (11).

Magnesium hydroxide

Magnesium hydroxide, also known as milk of magnesia, is commonly used as a laxative to treat constipation and in some antacids to treat heartburn (2, 12).

Magnesium aspartate

Magnesium aspartate is another common magnesium supplement that is highly absorbable by the body (4, 13).

Magnesium glycinate

Magnesium glycinate has been shown to have a relatively good absorption rate with less of a laxative effect.

According to some older research, this is likely because it’s absorbed in a different area of your intestine compared with many other forms of magnesium supplements (14).

Summary

Many types of magnesium supplements are available. It’s important to consider the absorption rate of supplements before making a purchase.

Dosage for constipation

Whether you are dealing with acute or chronic constipation, it can be uncomfortable.

Magnesium oxide and magnesium hydroxide are two magnesium compounds commonly used to promote bowel movements (15).

Magnesium hydroxide, or milk of magnesia, works as a laxative by pulling water into your intestines, which helps soften your stool and ease its passage (12).

The recommended dose depends on the product. Always follow the dosage instructions.

Exceeding the recommended intake could cause watery diarrhea or electrolyte imbalances (16).

Due to its laxative effect, milk of magnesia is generally used to treat acute constipation and not usually recommended for chronic cases.

Magnesium citrate is another magnesium supplement used to treat constipation, which helps draw water into the intestine to improve the consistency of stool (17).

The standard dose for magnesium citrate is 240 milliliters (mL) per day, which can be mixed with water and taken orally.

Summary

Magnesium citrate and magnesium hydroxide are common magnesium compounds used to treat constipation. For best results, always follow standard dosage recommendations on the label.

Dosage for sleep

Adequate magnesium levels are important for a good night’s sleep. Magnesium can help your mind relax and your body achieve deep, restorative sleep.

In fact, older studies in rats have shown that suboptimal magnesium levels led to poor sleep quality (18).

Currently, a limited number of studies have studied the effects of magnesium supplements on sleep quality, making it difficult to recommend a specific daily dose.

However, one review found that older adults with insomnia who took between 320–729 mg of magnesium per day from magnesium oxide or magnesium citrate were able to fall asleep significantly faster compared to a placebo (19).

Summary

Based on limited research, taking 320–729 mg of magnesium daily may help you fall asleep faster.

Dosage for blood sugar regulation

People with diabetes may be more likely to have low magnesium levels (20, 21).

High blood sugar levels can increase magnesium loss through urine, causing low magnesium levels in your blood.

Studies have shown that magnesium supplements may help regulate blood sugar by managing insulin action (22).

Insulin is a hormone that helps control blood sugar levels by signaling your cells to take in sugar from your blood.

One 3-month study in 42 people with diabetes found that supplementing with 250 mg of magnesium per day in the form of magnesium gluconate, oxide, and lactate improved levels of insulin, insulin resistance, and hemoglobin A1c, a marker of long-term blood sugar control (23).

However, another 2014 study found that people with diabetes and normal magnesium levels who received a daily total of 360 mg of magnesium from magnesium lactate showed no improvements in blood glucose regulation or insulin sensitivity over a 3-month period (24).

Therefore, more recent, high quality studies are needed to understand the effects of magnesium on blood sugar control for people with diabetes.

Summary

Doses of 250 mg of magnesium supplements daily have been shown to improve blood glucose levels in patients with diabetes, but more research is needed.

Dosage for reducing muscle cramps

Many conditions can cause muscle cramps.

Since magnesium is key to muscle function, a deficiency may cause painful muscle contractions.

Magnesium supplements are often marketed to prevent or improve muscle cramping.

Though research on magnesium supplements for muscle cramping is mixed, one older study found that participants who received 300 mg of magnesium daily for 6 weeks reported fewer muscle cramps compared with those who received a placebo (25).

Another study noted the ability of magnesium supplements to reduce the frequency of leg cramps during pregnancy, reporting that those who took 300 mg of magnesium daily experienced less frequent and less intense leg cramps, compared with those who took a placebo (26).

Still, more research is needed, as several other studies have found no effect of magnesium supplements on leg cramps (27, 28, 29).

Summary

Although further research is needed on magnesium and muscle cramps, taking 300 mg of magnesium daily may help decrease symptoms.

Dosage for depression

Studies have shown that magnesium deficiency may increase your risk of depression (30).

In fact, taking a magnesium supplement may improve depressive symptoms in some people.

One study found that taking a total of 248 mg of magnesium (from 2,000 mg of magnesium chloride) per day improved depressive symptoms in those with mild to moderate depression (31).

Moreover, another study found that taking 305 mg of magnesium (from 500 mg of magnesium oxide) for 8 weeks led to significant improvements in symptoms of depression in people with low magnesium levels (32).

While magnesium supplements may improve depression in those with magnesium deficiency, further research is needed to know if they can alleviate depression in those with normal magnesium levels.

Summary

Supplementing with 248–305 mg of magnesium per day has been shown to improve mood in people with depression and low magnesium levels.

Dosage for enhancing exercise performance

Various studies on magnesium supplements’ effects on exercise performance have found mixed results.

For example, one older study that used a dose of 365 mg of magnesium daily showed no significant change in exercise performance or muscle gain (33).

Researchers concluded that athletes who aren’t deficient in magnesium are unlikely to benefit from supplementation (33).

However, another 2014 study found that volleyball players who took 350 mg of magnesium per day showed improved athletic performance, compared with a control group (34).

Summary

Supplementing with magnesium at doses of 350 mg or higher per day may boost exercise performance, but results are mixed.

Dosage for improving PMS symptoms

Premenstrual syndrome (PMS) is a group of symptoms, including water retention, agitation, and headaches, that many experience about 1–2 weeks before their period (35).

Some older research has found that supplementing with magnesium may help improve PMS symptoms.

One older study found that taking 200 mg of magnesium (from magnesium oxide) daily improved water retention associated with PMS (36).

Another 2010 study found that supplementing with 250 mg of magnesium helped relieve PMS symptoms more effectively when combined with 40 mg of vitamin B6 (37).

Summary

Magnesium doses of 200–250 mg daily have been shown to improve PMS symptoms, including mood and water retention.

Dosage for migraines

People who experience migraines may be at risk of magnesium deficiency due to several factors, including a genetic inability to absorb magnesium efficiently or increased excretion of magnesium due to stress (38).

According to one review of five studies, supplementing with 600 mg (from magnesium dicitrate) could be a safe and effective option to reduce the frequency of migraine attacks (39).

Another study showed that taking 500 mg of magnesium from magnesium oxide was similarly as effective as a prescription medication at reducing the frequency and duration of migraine attacks over an 8-week period (40).

Summary

Supplementing with 500–600 mg of magnesium daily has been shown to prevent and possibly decrease the frequency and duration of migraines.

Possible side effects, concerns, and warnings

The National Academy of Medicine recommends not exceeding 350 mg of supplemental magnesium per day (2).

However, several studies have involved higher daily dosages.

It’s recommended to only take a daily magnesium supplement that provides more than 350 mg while under medical supervision.

Though magnesium toxicity is rare, taking certain magnesium supplements at high doses may cause diarrhea, nausea, and abdominal cramping.

Magnesium supplements may also interact with some medications, including antibiotics and diuretics (2).

Summary

Magnesium toxicity is rare, but be sure to speak with a healthcare professional before beginning to supplement with more than 350 mg daily.

The bottom line

Magnesium is involved in more than 300 biochemical reactions in your body and crucial for maintaining good health (41).

The RDA for magnesium is 310–420 mg for adults, depending on age and sex (2).

If you require a supplement, dosage recommendations can vary depending on your needs, such as to improve constipation, sleep, muscle cramps, or depression.

Most studies found positive effects with daily doses of 125–600 mg of elemental magnesium.

However, it’s best to consult a healthcare professional before taking a supplement, especially at higher doses.