Magnesium: Importance, Testing Methods and Normal Levels

What Is Magnesium?

Magnesium is a vital mineral that plays a crucial role in numerous processes within the body. 

It is essential for energy production, muscle contraction, nerve function, and maintaining strong bones. Magnesium also helps regulate blood sugar levels and supports a healthy immune system.

Abnormal magnesium levels, either too high or too low, can indicate issues with nutrient absorption, kidney function, or chronic health conditions. 

When Is Magnesium Testing Recommended?

Magnesium testing is suggested when there are signs of imbalance or to check general health, especially in older adults. 

A doctor may recommend magnesium testing in the following situations:

• Persistent muscle cramps or spasms
• Repeated pathological fractures (bone fractures without injury)
• Chronic fatigue or weakness
• Kidney-related symptoms, such as pain or frequent urination
• Unexplained nausea, vomiting, or diarrhea
• Prolonged constipation
• Rapid or irregular heartbeats (heart arrhythmias)
• Uncontrolled diabetes or insulin resistance
• Monitoring of conditions like autism, fibromyalgia or pre-eclampsia

Magnesium tests are also part of regular check-ups for people over the age of 45. It is especially important for people at risk of heart disease, diabetes, or kidney issues.

How Is Magnesium Testing Conducted?

Magnesium levels are usually measured through a blood test, specifically using a venous blood sample. This test is often included in broader health panels, such as a Complete Metabolic Panel (CMP) or a specific magnesium blood test. In addition, nutritional tests can assess magnesium levels to help identify deficiencies related to diet.

Here are the most common methods to test magnesium:

• Blood test (serum magnesium): A venous blood sample is taken to measure magnesium levels in the bloodstream. This is the most commonly used method.
• Urine test: A urine sample is used to determine how much magnesium is being excreted by the kidneys.
• Hair or nail test: These are used to assess long-term magnesium levels in the body and can provide insight into chronic deficiencies.

Special Preparations for the Test

• Avoid magnesium supplements for 24 hours before testing unless your doctor advises otherwise.
• If providing a hair or nail sample, avoid any cosmetic procedures (such as dyeing or chemical treatments) in the days leading up to the test, as these can affect the results.

What Are the Normal Magnesium Levels?

In Blood

Normal magnesium levels vary by age and are measured in milligrams per deciliter (mg/dL). The standard ranges for blood serum magnesium levels are as follows:

Children:

• Up to 2 years old - 1.6-2.7 mg/dL
• Up to 5 years old - 1.6-2.6 mg/dL
• Up to 8 years old — 1.6-2.5 mg/dL
• Up to 11 years old - 1.6-2.4 mg/dL
• Up to 17 years old - 1.6-2.3 mg/dL

Adults (over 17 years old): 1.7–2.3 mg/dL

In Urine

Magnesium levels in urine from a 24-hour sample typically range between 24 and 255 mg per day, depending on dietary intake and other factors.

Note: The units of measurement and the normal ranges can differ depending on the laboratory and the specific methods used.

What Do Abnormal Magnesium Levels Mean?

Abnormal magnesium levels, whether too high or too low, can indicate underlying health issues that require medical attention. Both extremes can have serious effects on the body, from muscle cramps to heart problems.

Magnesium High Levels

High magnesium levels, also known as hypermagnesemia, can occur when too much magnesium builds up in the body. This usually happens due to excessive intake or the body's inability to eliminate it.

Possible causes of high magnesium levels include:

• Dehydration: Low water intake or excessive fluid loss can cause magnesium to concentrate in the blood.
• Use of magnesium-containing products: Overuse of supplements, antacids, or laxatives can lead to magnesium buildup.
• Kidney failure: The kidneys are responsible for removing excess magnesium, and if they are not functioning properly, magnesium can accumulate.
• Endocrine disorders: Conditions such as hyperparathyroidism can cause magnesium to rise abnormally.
• Addison’s disease: This condition affects the adrenal glands, which can impact how the body handles magnesium.

• Work with your healthcare provider to identify and treat the underlying cause of high magnesium levels.
• Reduce magnesium intake through diet or supplements, as recommended by your doctor.
• Stay hydrated and avoid dehydration, which can worsen magnesium retention.
• Address any kidney-related issues promptly to prevent further complications.

Magnesium Low Levels

Low magnesium levels, or hypomagnesemia, are more common and often linked to a variety of lifestyle and health factors.

Possible causes of low magnesium levels include:

• Poor diet: A lack of magnesium-rich foods like leafy greens, nuts, and whole grains can lead to deficiencies.
• Digestive disorders: Conditions like Crohn’s disease or celiac disease can impair magnesium absorption.
• Uncontrolled diabetes: High blood sugar levels can cause excessive magnesium loss through urine.
• Long-term diuretic use: Some medications can cause the body to lose magnesium through increased urination.
• Chronic diarrhea or vomiting: These symptoms can lead to dehydration and the loss of important minerals, including magnesium.
• Excessive alcohol consumption: Alcohol can interfere with magnesium absorption and cause its levels to drop over time.

• Increase your intake of magnesium-rich foods such as spinach, almonds, and avocados.
• Consult your doctor about magnesium supplements if dietary changes alone are not enough.
• Address any underlying health conditions, especially those affecting the digestive system.
• Reduce alcohol consumption, as it can contribute to magnesium depletion.
• Stay hydrated to support normal magnesium levels.

Which Specialist Should You Consult?

If your magnesium levels are abnormal, you may need to consult a specialist depending on the root cause of the imbalance. The following healthcare providers can help:

• Neurologist: If magnesium deficiency is affecting your nerves or causing muscle spasms.
• Nephrologist: For kidney-related issues that are impacting magnesium regulation.
• Endocrinologist: To address any hormonal imbalances affecting magnesium levels.
• Gastroenterologist: If digestive disorders are interfering with magnesium absorption.
• Nutritionist: To help optimize your diet and ensure you are getting enough magnesium from food sources.
• Cardiologist: If heart irregularities, such as arrhythmias, are linked to abnormal magnesium levels.