What this marker measures
Blood magnesium represents only about 1% of total body magnesium; most is inside cells and bones. This means blood levels can appear normal while total body magnesium is actually depleted.
High or low: what it can mean
High Magnesium
High magnesium (hypermagnesemia) is uncommon in people with normal kidney function. It is most often seen with excess magnesium supplementation or antacid use, particularly in people with kidney disease.
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Low Magnesium
Low magnesium (hypomagnesemia) is more common than often recognized. Causes include chronic diarrhea, diuretics, excessive alcohol, poorly controlled diabetes, and low dietary intake. It can contribute to muscle cramps, fatigue, and anxiety.
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Lifestyle considerations
- •Magnesium-rich foods include nuts, seeds, dark chocolate, avocados, legumes, and whole grains
- •Excess alcohol and some diuretics deplete magnesium
Frequently asked questions
What is Magnesium?
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Magnesium participates in over 300 enzymatic reactions and is important for muscle and nerve function, blood sugar regulation, blood pressure, and protein synthesis.
What does Magnesium measure?
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Blood magnesium represents only about 1% of total body magnesium; most is inside cells and bones. This means blood levels can appear normal while total body magnesium is actually depleted.
What does high Magnesium mean?
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High magnesium (hypermagnesemia) is uncommon in people with normal kidney function. It is most often seen with excess magnesium supplementation or antacid use, particularly in people with kidney disease.
What does low Magnesium mean?
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Low magnesium (hypomagnesemia) is more common than often recognized. Causes include chronic diarrhea, diuretics, excessive alcohol, poorly controlled diabetes, and low dietary intake. It can contribute to muscle cramps, fatigue, and anxiety.
What supports healthy Magnesium levels?
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Magnesium-rich foods include nuts, seeds, dark chocolate, avocados, legumes, and whole grains. Excess alcohol and some diuretics deplete magnesium
Related biomarkers
Editorial note
LabTestly explains lab markers using plain-English educational content. Reference ranges may vary by laboratory and should be interpreted with a clinician.
Educational content · Editorially reviewed for clarity · Last updated
Common sources used for lab-test education
Not medical advice
This page is for general understanding only and does not replace medical advice from your clinician. Reference ranges can vary by laboratory, age, sex, pregnancy status, medications, and clinical context.