Magnesium Blood Test

A serum magnesium test measures the concentration of magnesium in your bloodstream. Magnesium supports strong bones, healthy muscles, stable energy production, and normal blood pressure. Because the body tightly regulates blood magnesium, even a modest drop can signal a meaningful deficit at the cellular level.

Why Test Magnesium?

Testing magnesium is important for identifying lifestyle-related risk factors early. People with high alcohol intake, diets low in whole foods, a history of digestive issues, or chronic constipation should test regularly. Athletes and frequent sauna users have increased magnesium needs. Monitoring your levels helps track the effect of dietary changes and supplementation over time.

What Do High Magnesium Levels Mean?

Elevated magnesium (hypermagnesemia) is usually caused by excessive supplementation or impaired kidney excretion. Conditions such as hypothyroidism, hyperparathyroidism, and dehydration can also raise levels. Early signs include nausea, vomiting, and facial flushing, which may progress to muscle weakness, low blood pressure, irregular heart rhythm, and in severe cases, respiratory distress.

What Do Low Magnesium Levels Mean?

Low magnesium (hypomagnesemia) may result from inadequate dietary intake, poor absorption, uncontrolled diabetes, prolonged diarrhoea, chronic alcohol use, or long-term diuretic therapy. Pregnancy, especially in the second and third trimesters, also increases demand. Chronic deficiency contributes to osteoporosis, hypertension, and cardiovascular disease.

Symptoms to Watch For

Muscle cramps and spasms
Fatigue and weakness
Numbness or tingling
Irregular heartbeat or palpitations
Nausea and vomiting
Seizures (severe deficiency)
Irritability or confusion

Who Should Get Tested?

Individuals with a diet low in vegetables, nuts, seeds, and whole grains
People with high alcohol consumption
Those taking proton pump inhibitors or diuretics long-term
Athletes and regular sauna users
Pregnant women, especially in the second and third trimesters
Anyone experiencing chronic muscle cramps, fatigue, or heart palpitations

How to Prepare for Your Test

No special preparation is required for this test. Bring valid ID to your appointment.

Order Your Blood Test

Test your Magnesium levels with an accredited Swedish laboratory. Results within days, reviewed by Wellth.

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Frequently Asked Questions

Can I have low magnesium even if my blood test is normal?

Yes. The body keeps blood magnesium levels stable, so intracellular levels can be depleted before serum values drop. Symptoms alongside a low-normal result may still warrant supplementation.

What foods are rich in magnesium?

Dark leafy greens, pumpkin seeds, almonds, dark chocolate, avocados, and legumes are excellent dietary sources of magnesium.

How does magnesium relate to heart health?

Magnesium helps maintain a regular heart rhythm and healthy blood pressure. Chronic deficiency is associated with an increased risk of cardiovascular disease, arrhythmias, and hypertension.

Reviewed by

Wellth Team

Wellth

Our content is written and reviewed by Wellth, and fact-checked against peer-reviewed research and current Swedish clinical guidelines.

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Medical Disclaimer

The information on this page is provided for informational purposes only and does not constitute professional medical advice, diagnosis, or treatment. Wellth provides health information and testing services but is not a substitute for clinical care. Always consult a qualified healthcare provider if you have questions about a medical condition. If you are experiencing severe or urgent symptoms, contact your doctor or call 1177 Vårdguiden. Blood test results should be interpreted by a qualified healthcare professional in the context of your complete medical history.