Magnesium deficiency, also known as hypomagnesemia, is an often-overlooked health problem.

While less than 2% of Americans have been estimated to experience magnesium deficiency, that percentage has been shown to be far greater in hospital and ICU patients and people with diabetes or alcohol use disorder (1).

In some cases, deficiency may be underdiagnosed since the obvious signs commonly don’t appear until your levels become severely low.

The causes of magnesium deficiency vary and can include (1):

  • starvation
  • certain medications, such as chemotherapy drugs and proton pump inhibitors
  • acute or chronic diarrhea
  • “hungry bone syndrome” after parathyroid or thyroid surgery
  • gastric bypass surgery

Health conditions such as diabetes, poor absorption, chronic diarrhea, and celiac disease are associated with magnesium loss. People with alcohol use disorder are also at an increased risk of deficiency (2).

This article lists 7 symptoms of magnesium deficiency.

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Twitches, tremors, and muscle cramps are signs of magnesium deficiency. In worst-case scenarios, deficiency may even cause seizures or convulsions (1, 3).

Scientists believe these symptoms are caused by a greater flow of calcium into nerve cells, which overexcites or hyperstimulates the muscle nerves (4).

While supplements may help relieve muscle twitches and cramps in some people with a deficiency, one review concluded that magnesium supplements are not an effective treatment for muscle cramps in older adults. Further studies are needed in other groups (5).

Keep in mind that involuntary muscle twitches may have many other causes. For example, stress or excessive caffeine could also cause involuntary muscle spasms.

They may also be a side effect of some medications or a symptom of a neuromuscular disease such as muscular dystrophy, multiple sclerosis, or myasthenia gravis.

While occasional twitches are common, you should see your doctor if your symptoms persist.

Summary

Common signs of magnesium deficiency include muscle twitches, tremors, and cramps. However, supplements are unlikely to reduce these symptoms in older adults or people who aren’t deficient in magnesium.

Mental health conditions are another possible effect of magnesium deficiency.

One example is apathy, which is characterized by mental numbness or lack of emotion. Worsened deficiency may even lead to delirium and coma (3).

Additionally, observational studies have associated low magnesium levels with an increased risk of depression (6).

Scientists have also speculated that magnesium deficiency might promote anxiety, but direct evidence is lacking (7).

One review concluded that magnesium supplements might benefit a subset of people with anxiety disorders, but the quality of the evidence is poor. Higher quality studies are needed before any conclusions can be reached (8).

In short, it seems that a lack of magnesium may cause nerve dysfunction and promote mental health conditions in some people.

Summary

Magnesium deficiency may cause lack of emotion, delirium, and even coma. Scientists have suggested that deficiency may also cause anxiety, but no strong evidence supports this idea.

Osteoporosis is a disorder characterized by weak bones and an increased risk of bone fractures.

Numerous factors influence the risk of developing osteoporosis, including:

  • aging
  • lack of exercise
  • poor dietary intake of vitamins D and K

Interestingly, magnesium deficiency is also a risk factor for osteoporosis. Deficiency might weaken bones directly, but it also lowers the blood levels of calcium, the main building block of bones (9, 10).

Studies in rats confirm that dietary magnesium depletion results in reduced bone mass. Although no such studies have been carried out in humans, research has associated poor magnesium intake with lower bone mineral density (11, 12).

Summary

Magnesium deficiency may be one of the risk factors for osteoporosis and bone fractures, though many factors influence this risk.

Fatigue, a condition characterized by physical or mental exhaustion or weakness, is another symptom of magnesium deficiency.

Keep in mind that everyone becomes fatigued from time to time. Typically, it simply means you need to rest. However, severe or persistent fatigue may be a sign of a health problem.

Since fatigue is a nonspecific symptom, its cause is impossible to identify unless it is accompanied by other symptoms.

Another more specific sign of magnesium deficiency is muscle weakness, which may be caused by myasthenia gravis (13).

Scientists believe the weakness is caused by the loss of potassium in muscle cells, a condition associated with magnesium deficiency (14, 15).

Therefore, magnesium deficiency is one possible cause of fatigue or weakness.

Summary

Magnesium deficiency may cause fatigue or muscle weakness. However, these are not specific signs of a deficiency unless they are accompanied by other symptoms.

Animal studies show that magnesium deficiency may increase blood pressure and promote high blood pressure, which is a strong risk factor for heart disease (16, 17).

While direct evidence in humans is lacking, several observational studies suggest that low magnesium levels or poor dietary intake may raise blood pressure (18, 19, 20).

The strongest evidence for the benefits of magnesium comes from controlled studies.

Several reviews have concluded that magnesium supplements may lower blood pressure, especially in adults with high blood pressure (21, 22, 23).

Put simply, magnesium deficiency may increase blood pressure, which, in turn, increases the risk of heart disease. Nevertheless, more studies are needed before its role can be fully understood.

Summary

Evidence suggests magnesium deficiency may raise blood pressure. Additionally, supplements may benefit people with high blood pressure.

Magnesium deficiency is sometimes seen in people with severe asthma (24, 25).

Additionally, magnesium levels tend to be lower in individuals with asthma than in people who do not have this condition (26, 27).

Researchers believe a lack of magnesium may cause the buildup of calcium in the muscles lining the airways of the lungs. This causes the airways to constrict, making breathing more difficult (28).

Interestingly, an inhaler with magnesium sulfate is sometimes given to people with severe asthma to help relax and expand the airways. For those with life threatening symptoms, injections are the preferred method of delivery (29, 30).

However, evidence for the effectiveness of dietary magnesium supplements in individuals with asthma is inconsistent (31, 32, 33).

In short, scientists believe severe asthma may be linked to magnesium deficiency in some people, but further studies are needed to investigate its role.

Summary

Magnesium deficiency has been associated with severe asthma. However, its role in the development of asthma is not entirely understood.

Heart arrhythmia, or irregular heartbeat, is among the most serious possible effects of magnesium deficiency (34).

Arrhythmia can range from causing no symptoms to causing very serious symptoms. In some people, it may cause heart palpitations, which are pauses between heartbeats.

Other possible symptoms of arrhythmia include:

  • lightheadedness
  • shortness of breath
  • chest pain
  • fainting
  • dizziness
  • fatigue

In the most severe cases, arrhythmia may increase the risk of stroke or heart failure.

Scientists believe that an imbalance of potassium levels inside and outside of heart muscle cells — a condition associated with magnesium deficiency — may be to blame (35, 36).

Some people with congestive heart failure and arrhythmia have been shown to have lower magnesium levels than people who don’t have heart failure.

In a small study in 68 people with heart failure, magnesium injections significantly improved participants’ heart function (37).

Magnesium supplements may also help reduce symptoms in some people with arrhythmia (38).

Summary

Magnesium deficiency can cause or worsen arrhythmia, or irregular heartbeat, which may increase the risk of more serious complications, such as a stroke or heart failure.

The table below shows the Recommended Dietary Allowance (RDA) or adequate intake (AI) of magnesium for males and females in the United States (39).

AgeMaleFemalePregnancyLactation
Birth to 6 months30 mg*30 mg*
7–12 months75 mg*75 mg*
1–3 years80 mg80 mg
4–8 years130 mg130 mg
9–13 years240 mg240 mg
14–18 years410 mg360 mg400 mg360 mg
19–30 years400 mg310 mg350 mg310 mg
31–50 years420 mg320 mg360 mg320 mg
51+ years420 mg320 mg

*Adequate intake

Although many people don’t reach the RDA for magnesium, there are plenty of magnesium-rich foods to choose from.

Magnesium is widely found in both plant- and animal-based foods. The richest sources are seeds and nuts, but whole grains, beans, and leafy green vegetables are also relatively good sources.

Below is the magnesium content in 3.5 ounces (100 grams) of some of the best sources (40, 41, 42, 43, 44):

  • almonds: 279 mg
  • pumpkin seeds: 550 mg
  • dark chocolate: 228 mg
  • peanuts: 176 mg
  • popcorn: 144 mg

For example, just 1 ounce (28.4 grams) of almonds provides 19% of the RDA for magnesium.

Other great sources of magnesium include:

  • flaxseed
  • sunflower seeds
  • chia seeds
  • cocoa
  • coffee
  • cashews
  • hazelnuts
  • oats

Magnesium is also added to many breakfast cereals and other processed foods.

If you have a health condition that causes your body to lose magnesium, such as diabetes, it’s important to eat plenty of magnesium-rich foods or take supplements.

Talk with your doctor about creating a plan to increase your magnesium intake that works well for your needs.

Summary

Seeds, nuts, cocoa, beans, and whole grains are great sources of magnesium. For optimal health, try to eat magnesium-rich foods every day.

While some older research suggests that 48% of Americans are not getting enough magnesium, true magnesium deficiency is not very common — less than 2%, according to one estimate (45).

The symptoms of magnesium deficiency are usually subtle unless your levels become severely low.

Deficiency may cause:

  • fatigue
  • muscle cramps
  • mental health conditions
  • irregular heartbeat
  • osteoporosis

If you believe you may have a magnesium deficiency, you should speak with your doctor.

Testing for magnesium levels can be challenging because magnesium tends to collect in tissue and bone, not blood.

An RBC blood test, which measures magnesium levels in the red blood cells themselves, is more sensitive and accurate than the more commonly ordered serum magnesium blood test (39, 46).

Whatever the outcome, try to regularly eat plenty of magnesium-rich whole foods, such as nuts, seeds, grains, and beans.

These foods are also high in other healthy nutrients. Including them in your diet not only lowers your risk for magnesium deficiency but also supports your overall health.