Magnesium · low result
What does a low Magnesium mean?
Short answer
Low magnesium is common and often missed: proton-pump inhibitors, diuretics, alcohol, diarrhea, poorly controlled diabetes and low intake are the usual causes. Because most magnesium is inside cells, a normal serum level doesn't exclude deficiency, but a low one confirms it. Low magnesium drags potassium and calcium down with it and causes cramps, palpitations and fatigue.
Medically reviewed by Youmna DiStefano, MD · Last reviewed September 2026
When does this result need same-day care?
- Low magnesium with palpitations, an irregular pulse or seizures — same-day care
What is the normal range for Magnesium?
- age 18+: 1.70 – 2.20 mg/dL
Common in alcohol use, diuretic use, GI losses, or poor diet. Can cause muscle cramps and arrhythmias.
Full reference table, citations and testing options: Magnesium biomarker page.
What are the common causes of low Magnesium?
- Proton-pump inhibitors (long-term), diuretics, some antibiotics and chemotherapy
- Alcohol use disorder
- Chronic diarrhea, malabsorption, bariatric surgery
- Poorly controlled diabetes (urinary loss)
- Low dietary intake
What symptoms go with low Magnesium?
- Muscle cramps, twitches, weakness
- Palpitations
- Fatigue, poor sleep
- Numbness, tremor when more severe
What do clinicians usually check next?
- Potassium and calcium (often low together)
- Medication and alcohol review
- Kidney function
- Repeat after correcting the cause
Follow-up tests available at TestWell: Calcium ($26.99).
How do you recheck Magnesium?
Prices are cash-pay; every order adds one $6 lab processing fee. Physician authorization is included; no insurance or referral needed.
| Test or panel | Type | Price | Fasting | Results |
|---|---|---|---|---|
| Fitness & Performance Panel | Panel · 8 tests | $119.99 | Yes | 2–5 business days |
| Sleep Health Panel | Panel · 8 tests | $129.99 | Yes | 3–5 business days |
| Vitamin & Mineral Deficiency Panel | Panel · 9 tests | $189.99 | No | 3–5 business days |
| Magnesium | Test | $19.99 | No | 2–4 business days |
Common questions
Can my magnesium be low even if the blood test is normal?
Yes — serum magnesium is about 1% of the body's total. A low result is meaningful; a normal one doesn't rule deficiency out when symptoms and risk factors fit.
Sources
Educational content, not a diagnosis. Lab results are one input; a clinician interprets them with your history and exam.