Magnesium deficiency
Symptoms, at-risk groups, and clinical context for magnesium deficiency. Sourced from NIH Office of Dietary Supplements and StatPearls.
Subclinical magnesium inadequacy is common — an estimated 48% of Americans consume less than the EAR. Severe deficiency (hypomagnesemia, serum <0.75 mmol/L) is less common but significant in hospitalized patients and those on certain medications. Symptoms are often nonspecific, making it easy to miss.
Common symptoms
- Muscle cramps, twitches, or spasms
- Muscle weakness
- Fatigue and low energy
- Loss of appetite, nausea, or vomiting
- Irritability, anxiety, or restlessness
- Sleep disturbances
- Headaches or migraines
- Numbness or tingling
- Abnormal heart rhythms (in severe deficiency)
- Tremors
At-risk groups
- Long-term proton pump inhibitor users (omeprazole, esomeprazole, lansoprazole)
- People taking diuretics (furosemide, hydrochlorothiazide)
- Older adults (decreased absorption, increased renal loss)
- People with type 2 diabetes (urinary magnesium losses)
- People with GI conditions (Crohn's, celiac, chronic diarrhea)
- People with alcohol use disorder
- Endurance athletes (sweat losses)
- People eating predominantly processed foods (low magnesium intake)
When to see a doctor: Persistent muscle cramps, unexplained anxiety with sleep problems, or symptoms in any at-risk group warrants a serum magnesium test. Note: serum levels reflect only ~1% of body magnesium and can be normal even when tissue stores are depleted; RBC magnesium or magnesium loading tests are more sensitive.
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Related deficiencies
Nutrients with overlapping symptoms — useful when investigating an unclear clinical picture.