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, one study suggests that up to 75% are not meeting their recommended intake (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. They range from inadequate dietary intake to loss of magnesium from the body (2).

Health problems associated with magnesium loss include diabetes, poor absorption, chronic diarrhea, celiac disease and hungry bone syndrome. People with alcoholism are also at an increased risk (3, 4).

This article lists 7 symptoms of magnesium deficiency.

Young Woman Feeling Numb and Weak

Twitches, tremors and muscle cramps are signs of magnesium deficiency. In worst case scenarios, deficiency may even cause seizures or convulsions (5, 6).

Scientists believe these symptoms are caused by a greater flow of calcium into nerve cells, which overexcites or hyperstimulates the muscle nerves (7).

While supplements may relieve muscle twitches and cramps in deficient individuals, one review concluded that magnesium supplements are not an effective treatment for muscle cramps in older adults. Further studies are needed in other groups (8).

Keep in mind that involuntary muscle twitches may have many other causes. For example, they may be caused by stress or too much caffeine.

They may also be a side effect of some medications or a symptom of a neurological disease, such as neuromyotonia or motor neuron disease.

While occasional twitches are normal, 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 people who aren’t deficient.

Mental disorders are another possible consequence of magnesium deficiency.

These include apathy, which is characterized by mental numbness or lack of emotion. Worsened deficiency may even lead to delirium and coma (5).

Additionally, observational studies have associated low magnesium levels with an increased risk of depression (9).

Scientists have also speculated that magnesium deficiency might promote anxiety, but direct evidence is lacking (10).

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 (11).

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

Summary Magnesium deficiency may cause mental numbness, 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.

The risk of getting osteoporosis is influenced by numerous factors. These include old age, lack of exercise and a poor 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 (12, 13, 14, 15).

Studies in rats confirm that dietary magnesium depletion results in reduced bone mass. Although no such experiments have been done in people, studies have associated poor magnesium intake with lower bone mineral density (16, 17).

Summary Magnesium deficiency may increase the risk of osteoporosis and bone fractures, though this risk is influenced by many factors.

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 non-specific symptom, its cause is impossible to identify unless it is accompanied by other symptoms.

Another, more specific sign of magnesium deficiency is muscle weakness, also known as myasthenia (18).

Scientists believe the weakness is caused by the loss of potassium in muscle cells, a condition associated with magnesium deficiency (19, 20).

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 (21, 22).

While direct evidence is lacking in humans, several observational studies suggest that low magnesium levels or poor dietary intake may raise blood pressure (23, 24, 25).

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 (26, 27, 28).

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 patients with severe asthma (29).

Additionally, magnesium levels tend to be lower in individuals with asthma than in healthy people (30, 31).

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 (7, 32).

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 route of delivery (33, 34).

However, evidence for the effectiveness of dietary magnesium supplements in asthmatic individuals is inconsistent (35, 36, 37).

In short, scientists believe severe asthma may be a symptom of magnesium deficiency in some patients, 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.

Among the most serious symptoms of magnesium deficiency is heart arrhythmia, or irregular heartbeat (38).

The symptoms of arrhythmia are mild in most cases. Often, it has no symptoms at all. However, 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 or fainting. 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 may be to blame, a condition associated with magnesium deficiency (39, 40).

Some patients with congestive heart failure and arrhythmia have been shown to have lower magnesium levels than healthy people. Treating these patients with magnesium injections significantly improved their heart function (41).

Magnesium supplements may also reduce symptoms in some patients with arrhythmia (42).

Summary One of the symptoms of magnesium deficiency is heart 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 daily allowance (RDA) or adequate intake (AI) for men and women in the United States.

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.

It is widely found in both plants and animal-sourced foods. The richest sources are seeds and nuts, but whole grains, beans and leafy green vegetables are also relatively rich sources.

Below is the magnesium content in 3.5 ounces (100 grams) of some of its best sources (43):

  • Almonds: 270 mg
  • Pumpkin seeds: 262 mg
  • Dark chocolate: 176 mg
  • Peanuts: 168 mg
  • Popcorn: 151 mg

For example, just one ounce (28.4 grams) of almonds provides 18% of the RDI for magnesium.

Other great sources include flaxseeds, sunflower seeds, chia seeds, cocoa, coffee, cashew nuts, hazelnuts and oats. Magnesium is also added to many breakfast cereals and other processed foods.

If you have a health disorder that causes a loss of magnesium from the body, such as diabetes, you should make sure to eat plenty of magnesium-rich foods or take supplements.

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

Magnesium deficiency is a widespread health problem.

Some studies suggest that 75% of Americans do not meet their dietary requirements for magnesium. However, true deficiency is much less common — less than 2%, according to one estimate.

The symptoms of magnesium deficiency are usually subtle unless your levels become severely low. Deficiency may cause fatigue, muscle cramps, mental problems, irregular heartbeat and osteoporosis.

If you believe you may have a magnesium deficiency, your suspicions can be confirmed with a simple blood test. You should speak with your doctor to rule out other possible health problems.

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

These foods are also high in other healthy nutrients. Including them in your diet not only lowers your risk of magnesium deficiency, but it also promotes your overall health.