Magnesium (Mg)
Magnesium is involved in over 300 enzymatic reactions including energy production, protein synthesis, muscle contraction, nerve function, and blood sugar regulation. About 60% of body magnesium is in bones, 39% in cells, and only 1% in blood — making blood levels a poor indicator of total body stores. Deficiency is common but often undiagnosed.
Reference Ranges
Male
1.7 – 2.2
mg/dL
Female
1.7 – 2.2
mg/dL
Child
1.7 – 2.3
mg/dL
Ages 1–18
Reference ranges may vary by laboratory. Always compare with the range printed on your lab report.
What Low Levels Mean
Low magnesium (hypomagnesemia) causes muscle cramps, tremors, fatigue, numbness, tingling, and irregular heartbeat. It also makes it harder to correct low calcium and low potassium — these three deficiencies often coexist. Causes include poor diet, alcohol use, diarrhea, diabetes, and certain medications (PPIs, diuretics).
What High Levels Mean
High magnesium (hypermagnesemia) is rare and almost always caused by kidney failure or excessive magnesium supplementation/antacid use. Symptoms include nausea, muscle weakness, low blood pressure, and slowed breathing. Severe cases can cause cardiac arrest.
Frequently Asked Questions
What foods are rich in magnesium?
Dark leafy greens (spinach), nuts (almonds, cashews), seeds (pumpkin), whole grains, dark chocolate, bananas, and legumes (rajma, chana). Despite this, up to 50% of people in developed countries get less than the recommended 400 mg/day.
Can magnesium supplements help with sleep and anxiety?
Magnesium may help — it plays a role in GABA signaling (the calming neurotransmitter) and melatonin production. Magnesium glycinate and threonate are preferred for sleep/anxiety. However, if your blood magnesium is normal, supplements may not provide additional benefit.
Why is magnesium often low alongside potassium?
Magnesium is required for the cellular pump that maintains potassium inside cells. When magnesium is low, cells lose potassium into the blood, which is then excreted by the kidneys. This is why low potassium that doesn't respond to supplements often requires magnesium correction first.
This information is for educational purposes only and should not replace professional medical advice. Always consult your doctor for interpretation of your test results.
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