Low magnesium symptoms: What are the early signs of low magnesium?

Overview: What does low magnesium (hypomagnesemia) feel like?

Magnesium is an important mineral that is vital to many processes in the body, particularly energy production, nerve function, muscle contractions, and heartbeats. When magnesium falls to levels lower than normal in the blood, there are usually no symptoms. Symptoms usually only appear when magnesium levels fall too low. The earliest sign of low magnesium is feeling sick: nausea, vomiting, tiredness, weakness, and lack of interest in food. If untreated, it then becomes evident that things are going wrong with the nerves, the muscles, and the heart. People notice their hands are shaking, their muscles are stiff or crampy, they might start jerking their hands, and their heartbeats may not feel right. They might get more confused or disoriented than usual. Because low magnesium may be caused by a serious medical condition, medical help is needed when symptoms of low magnesium appear. Fortunately, it usually only takes a few days to get magnesium levels back to normal, but it may take longer to improve the underlying problem.

What are the early signs of low magnesium?

Most people will not experience symptoms of low magnesium until levels start to get critically low. The most common early signs of low magnesium are:

• Nausea

• Vomiting

• Loss of appetite

• Tiredness

• Weakness

Other low magnesium symptoms

Critically low magnesium will affect the nerve, muscle, and heart function. The signs of magnesium deficiency include:

• Muscle cramps

• Muscle spasms

• Muscle twitching

• Eyelid twitching

• Rapid up and down eye movements

• Attacks of jerking, writhing, and grimacing

• Numbness

• Tingling

• Depression

• Agitation

• Heart rhythm abnormalities

• Heart spasms

• Delirium

• Psychosis

• Coma

Low levels of magnesium can disrupt kidney function and then cause low calcium and potassium levels. Many of the symptoms of these disorders are similar to low magnesium, but some are unique to these deficiencies:

• Dry skin

• Brittle nails

• Throat spasms

• Constipation

• Lightheadedness

• Excessive urination

• Excessive thirst

• Low blood pressure

• Excessive muscle weakness

• Paralysis

Source: Hypomagnesemia, StatPearls

Hypermagnesemia vs. hypomagnesemia symptoms

Too much magnesium in the body can also be a problem, but it is rare. High magnesium blood levels are most commonly encountered in people with kidney disease, or those who take too many magnesium products, such as antacids Most people with hypermagnesemia will have no symptoms. When magnesium levels become too high, however, it will clearly affect the nervous system and the muscles.

Sources: 

• Hypomagnesemia, StatPearls

• Hypermagnesemia, StatPearls

Types of low magnesium: How can I tell which one I have? 

Low magnesium is diagnosed when magnesium serum levels fall below normal. What’s normal? There’s a bit of disagreement on that question. Magnesium in the blood represents only a small fraction of the amount of magnesium in the body, so blood magnesium levels don’t give that much information. However, healthcare professionals would prefer that levels of magnesium in the blood be somewhere above 1.7 milligrams per deciliter (mg/dL). Symptoms usually appear when blood magnesium falls to 1.2 mg/dL. Low magnesium is classified by healthcare professionals as having no symptoms, mild symptoms, or severe symptoms. They will also classify low magnesium based on whether it’s a temporary problem or an ongoing problem. This is because long-term hypomagnesemia can cause low potassium (hypokalemia) and low calcium. It is also associated with a host of chronic illnesses, such as high blood pressure and Type 2 diabetes. 

When to see a doctor for low magnesium symptoms

See a doctor when experiencing any symptoms that you suspect are due to low magnesium. In addition, calcium and potassium may also be low. Severe hypomagnesemia symptoms, such as heart symptoms, seizures, mental aberrations, and coma, require emergency medical care.

A doctor will diagnose low magnesium by taking a medical history and performing a physical exam. A blood test will be performed to measure magnesium and other electrolyte levels, as well as a full metabolic panel. An electrocardiogram may also be performed to spot any potential problems with the heart. A urine sample that measures the amount of magnesium excreted in the urine can help diagnose the cause. In addition to the medical history and physical, other tests may be needed to pin down the cause.

Complications of low magnesium

Low magnesium can lead to potentially life-threatening heart rhythm problems, including atrial fibrillation and ventricular arrhythmias. 

Both low calcium and low potassium can be caused by the long-term effects of low magnesium on the kidneys and the parathyroid gland. Long-term, untreated hypomagnesemia also increases the risk of developing other health issues, including high blood pressure, cardiovascular disease, type 2 diabetes, osteoporosis, and migraines.

Source: Magnesium: fact sheet for health professionals, National Institutes of Health (NIH) Office of Dietary Supplements

How to treat low magnesium symptoms

Low magnesium requires treatment. Magnesium levels need to be brought back to normal. For people with mild or no symptoms, the standard treatment is taking oral magnesium supplements, such as magnesium citrate or magnesium oxide. Severe symptoms, particularly if the heart is involved, will require intravenous magnesium sulfate to correct levels more rapidly. In addition, any underlying condition, such as pancreatitis, Crohn’s disease, or any kidney issue, will also need treatment.

RELATED: Which magnesium supplement is right for me?

Signs low magnesium is getting better

Magnesium levels in the blood can be corrected in anywhere from a few days to a few weeks, depending on the cause. As magnesium levels in the blood and body return to normal, symptoms will fade, as will symptoms of calcium and potassium deficiency.

FAQs about low magnesium symptoms

How do you know if your magnesium is low?

You don’t know if magnesium levels are low unless a blood test is performed to measure magnesium levels. You may have a suspicion that your magnesium levels are low if there are symptoms, but not everybody has symptoms of magnesium deficiency. Minor symptoms aren’t specific to low magnesium concentrations in the body. The best solution is to increase magnesium intake by eating magnesium-rich foods. Foods high in magnesium include cereals, whole grains, cashews, and leafy greens. Once you’ve increased your dietary intake of magnesium, figure out if you’re at risk for low magnesium. Medical conditions that cause low magnesium, like Celiac disease or a swollen pancreas, have other symptoms and will generally require a healthcare provider’s help. Alcohol use disorder, anorexia, and chronic diarrhea cause low magnesium and are generally easy to spot. When taking any prescription or over-the-counter drug, such as proton-pump inhibitors, find out if hypomagnesemia is a side effect. If you have risk factors for low magnesium, ask a healthcare provider if they think testing magnesium levels is necessary.

What are the symptoms of low potassium and magnesium?

Long-term low magnesium levels can also cause potassium deficiencies. Both low magnesium and low potassium are potentially very serious. Low magnesium generally causes problems with muscle movements. Signs of severe low magnesium include muscle twitching, spasms, eyelid twitching, and similar issues. It can also affect the heart rate. Low potassium makes it harder to use muscles and nerves. People with low potassium will also have muscle spasms, but the muscles will feel weaker. In fact, they can get so weak that it gets hard to move anything. Hands and feet might tingle, burn, or get numb. People get lightheaded and faint. The colon slows down, so constipation becomes a problem.

Why do people with alcoholism have low magnesium?

Chronic alcoholism has so many effects on the body that any number of them can cause low magnesium:

• Poor nutrition

• Vomiting and diarrhea

• Swollen pancreas (a common problem of heavy drinking) interferes with magnesium absorption

• Other gut problems that interfere with intestinal absorption

• Kidney disease increases urine depletion of magnesium

• Ketoacidosis due to alcoholism also increases urine depletion of magnesium

And those are just some of the reasons.

What causes low magnesium in cancer patients?

Cancer and cancer treatment provide several possible causes for low magnesium: 

• In some cases, low magnesium is due to the effects of certain types of cancer drugs (cisplatin) or supportive drugs (diuretics or proton-pump inhibitors). 

• Simply not eating enough will mean not getting enough magnesium. 

• Vomiting and diarrhea are common issues with cancer and cancer treatments that also cause nutrient deficiencies. 

• Gut problems and pancreatitis are common. 

• Spending a period of time with very little food intake can lead the body to push magnesium into cells when the person starts eating again, lowering serum magnesium.

Suffice it to say that cancer treatment involves constant vigilance on the part of the healthcare team. Regular blood and urine testing to catch issues like low magnesium is a normal part of the routine.

Source: Hypomagnesemia in the cancer patient, Kidney360

What’s next? Additional resources for people with low magnesium symptoms

Test and diagnostics

• Hypomagnesemia, StatPearls

• Hypomagnesemia: a clinical perspective, International Journal of Nephrology and Renovascular Disease

Treatments

• Hypomagnesemia, StatPearls

• Magnesium: fact sheet for health professionals, National Institutes of Health (NIH) Office of Dietary Supplements

Scientific studies and clinical trials

• Hypomagnesemia in the cancer patient, Kidney360

More information on related health conditions

• Hypocalcemia, Cleveland Clinic

• Hypermagnesemia, StatPearls

• What causes low potassium?, SingleCare