РусскийEnglishEspañol — próximamenteFrançais — bientôtDeutsch — in VorbereitungItaliano — in arrivoAll languages
Magnesium
An electrolyte for muscles, nerves and the heart. Deficiency shows as cramps and weakness; excess occurs mainly in kidney failure.
Other names: Magnesium, MgSection: Blood chemistry
Updated: August 31, 2026·MedProtect editorial team Reference information — not a diagnosis or a prescription
In shortMagnesium is an electrolyte for muscles, nerves and the heart. A typical blood range is 1.7–2.2 mg/dL (0.70–0.91 mmol/L). Deficiency is driven by gut losses, diuretics and diabetes; excess occurs almost only in kidney failure and magnesium overdosing.
Reference ranges
Group
Reference range
Adults
1.7–2.2 mg/dL (0.70–0.91 mmol/L)
The source gives 1.7–2.2 mg/dL (0.70–0.91 mmol/L). Because blood holds under one percent of the body's magnesium, a normal level does not exclude hidden deficiency: with symptoms, the doctor weighs the clinical picture and further tests. Reference ranges vary between laboratories and assays — use the range printed on your own lab report.
Check your value
Enter the number from your lab report — see how it compares with the typical range. Mind the units shown in the chosen row.
A rough comparison with a typical range, not a diagnosis. Reference ranges vary between laboratories — check the range on your own report and let a clinician interpret the result.
What this marker is
Magnesium is a mineral involved in hundreds of enzymatic reactions: muscle and nerve function, heart rhythm, blood pressure and glucose regulation. Most of the body's supply is stored in bones and inside cells — less than one percent circulates in blood.
A blood test therefore shows only the 'visible' share: with mild deficiency the blood level can stay within range. Overt deficiency develops with prolonged diarrhea, diuretic use, alcohol use disorder, poor nutrition and diabetes; excess — almost always with kidney failure or overdosing on magnesium-containing medicines.
When it is high
Kidney failureThe kidneys excrete magnesium — when they fail, the level rises. The main cause of hypermagnesemia.
Magnesium overdoseProlonged use of magnesium-containing laxatives and antacids, especially with kidney disease.
Hypothyroidism and Addison's diseaseEndocrine causes of a moderate rise.
When it is low
Gut lossesProlonged diarrhea, vomiting, malabsorption, Crohn's disease — magnesium is lost or not absorbed.
Diuretics and some medicinesLoop diuretics, certain antibiotics and chemotherapy drugs increase magnesium excretion.
DiabetesWith high glucose, more magnesium is lost in urine.
Poor nutrition and alcohol use disorderLow intake combined with increased losses — the typical deficiency combination.
What can skew the result
These factors can shift the value without any disease — worth considering before a retest:
DiureticsDiarrhea and vomitingMagnesium medicines, laxatives and antacidsDiabetes
How to prepare
Blood from a vein; special preparation is usually unnecessary — follow your lab's rules. Tell your doctor about magnesium-containing medicines, laxatives, antacids and diuretics: all of them affect the result.
When a retest makes sense
If abnormal — 2–4 weeks after the cause is corrected; during magnesium therapy — as the doctor advises.
Who usually reviews this result
A result outside the reference range is usually reviewed by: GP; for cramps and neurological complaints — neurologist; for kidney disease — nephrologist. Bring your lab report and any previous results to the appointment.
Names used on lab reports
Your report may use any of these names: MagnesiumMgSerum magnesiumMg2+
Units and conversion
Measured in: mmol/L
mmol/L=mg/dL
mg/dL = mmol/L × 2.431. Example: 0.80 mmol/L = 1.9 mg/dL. Results are rounded to 2 decimal places.
Several markers on your report?
See how MedProtect explains results in the app: the whole report, a check of the recognized values, and a clear breakdown.
Sometimes, but far from always: cramps have many causes (dehydration, exertion, varicose veins, other electrolyte deficits). A magnesium test together with potassium and calcium helps the doctor sort it out.
Magnesium is normal but I have deficiency symptoms — how?
Blood holds under one percent of the supply: the body maintains the level from bones and cells. With persistent symptoms the doctor weighs the clinical picture, not just the number on the report.
Is excess magnesium from supplements dangerous?
In healthy people the kidneys excrete the surplus, and excess from supplements usually only loosens the stool. The real risk is in kidney failure: magnesium medicines there are prescribed only by a doctor.
We use cookies and Yandex.Metrika for visit statistics — no advertising tracking and no session recording. The counter loads only after your consent. Privacy policy.