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⚠ Severe deficiency (<0.50 mmol/L) causes secondary hypocalcemia and hypokalemia that will not correct until magnesium is repleted first [1].
⚠ Separate from bisphosphonates, fluoroquinolones, tetracyclines, and levothyroxine by at least 2 hours [1].
⚠ Potentiates muscle relaxants and calcium channel blockers [1].
🥗 Food first — build your daily 420 mg/ 320 mg
Check the foods you regularly eat — the bar fills toward your daily target.
Pumpkin seeds (28g)156 mg
Almonds (28g)80 mg
Spinach (½ cup cooked)78 mg
Cashews (28g)74 mg
Black beans (½ cup)60 mg
Dark chocolate (28g)50 mg
Avocado (1 medium)58 mg
Brown rice (½ cup cooked)42 mg
Check your regular foods above
☑ Risk checker
Chronic alcohol use (30–80% have Mg depletion due to renal wasting and poor intake) [3]
Type 2 diabetes (25–38% have hypomagnesemia; insulin resistance increases urinary Mg loss) [3]
Long-term PPI use (>1 year; FDA warning 2011) [5]
Loop or thiazide diuretic therapy [3]
Inflammatory bowel disease (Crohn, ulcerative colitis — impaired absorption) [1]
Elderly with poor dietary quality [1]
Calcineurin inhibitor therapy (tacrolimus, cyclosporine) [3]
Chronic diarrhea or malabsorption syndromes [1]
Select factors
🔬 Lab interpreter
Recommended test
Serum magnesium
Serum magnesium
Reference range / target
1.7–2.2 mg/dL (0.70–0.91 mmol/L). Note: serum Mg reflects only 1% of total body stores — normal serum does not exclude intracellular depletion [3]
1.7–2.2 mg/dL (0.70–0.91 mmol/L). Note: serum Mg reflects only 1% of total body stores — normal serum does not exclude intracellular depletion [3]
When to test
Suspected deficiency; chronic PPI/diuretic use; muscle cramps; arrhythmias; refractory hypokalemia
Full lab monitoring ↓Suspected deficiency; chronic PPI/diuretic use; muscle cramps; arrhythmias; refractory hypokalemia
⚕ For professionals — confirm ranges against your local laboratory.
Clinical verdict
Subclinical deficiency affects up to 30% of the general population [2]. Serum magnesium is a poor marker (only 1% of body stores) — consider RBC magnesium or ionized magnesium for accurate assessment [1]. Glycinate form preferred for tolerability and sleep; citrate for cost-effectiveness. Start 200 mg, titrate upward — loose stools indicate absorptive capacity exceeded [2].
1 Am I deficient?
United States (subclinical)48%
Europe30%
Middle East35%
East Asia25%
South Asia40%
Australia33%
What happens as status declines
Subclinical deficiency — serum 0.75–0.85 mmol/L
Serum levels may appear normal while intracellular stores are depleted. Muscle cramps (especially nocturnal calf cramps), fatigue, irritability, poor sleep quality. Often attributed to aging or stress rather than magnesium status [2].
Moderate deficiency — serum <0.75 mmol/L
Persistent muscle spasms and fasciculations, numbness and tingling in extremities, personality changes, abnormal heart rhythms (premature atrial and ventricular contractions). Reduced insulin sensitivity and elevated blood pressure [1].
Severe deficiency — serum <0.50 mmol/L
Tetany, seizures, cardiac arrhythmias (torsades de pointes, ventricular tachycardia). Secondary hypocalcemia and hypokalemia (magnesium is required for parathyroid hormone secretion and renal potassium retention). Hospitalization typically required for intravenous repletion [1].
Risk factors
• Chronic alcohol use (30–80% have Mg depletion due to renal wasting and poor intake) [3]
• Type 2 diabetes (25–38% have hypomagnesemia; insulin resistance increases urinary Mg loss) [3]
• Long-term PPI use (>1 year; FDA warning 2011) [5]
• Loop or thiazide diuretic therapy [3]
• Inflammatory bowel disease (Crohn, ulcerative colitis — impaired absorption) [1]
• Elderly with poor dietary quality [1]
• Calcineurin inhibitor therapy (tacrolimus, cyclosporine) [3]
• Chronic diarrhea or malabsorption syndromes [1]
🧬 How Magnesium works ▼
2 How much do I need?
👤 Adults: Specific dosage data under clinical review
👴 Elderly: Specific dosage data under clinical review
🤰 Pregnancy: Specific dosage data under clinical review
👦 Pediatric: See guidance
RDA: 80 mg (1-3 years), 130 mg (4-8 years), 240 mg (9-13 years). Deficiency is uncommon in children consuming a varied diet [1].
🏃 Athletes: Specific dosage data under clinical review
⚖️ Obesity: Standard dose
Fat-soluble compounds may require dose adjustment in obesity.
🩺 Renal: Consult specialist
Dose adjustment may be needed in renal impairment.
🌱 Vegan: Standard dose
How to take
🍽 Timing: Evening dosing may support sleep quality (Mg glycinate or threonate). Can be taken any time with food [4].
💊 With food: Take with food to reduce GI side effects, especially for magnesium oxide and citrate [4].
🚫 Avoid: Do not take simultaneously with bisphosphonates, fluoroquinolones, or tetracyclines. Separate by 2+ hours [4].
3 Which form?
| Form | Bioavailability | Vegan | Cost |
|---|---|---|---|
| ['Magnesium glycinate', 'preferred', 'Chelated with glycine. Superior bioavailability, minimal GI side effects. Preferred for deficiency correction and sleep support. The glycine component has additional calming effects.'] | Standard | Check label | |
| ['Magnesium citrate', '', 'Well-absorbed organic salt. Can have mild laxative effect at higher doses. Common and cost-effective form.'] | Standard | Check label | |
| ['Magnesium oxide', '', 'High elemental magnesium content (60%) but poor bioavailability (approximately 4%). Primarily used as an osmotic laxative.'] | Standard | Check label | |
| ['Magnesium taurate', '', 'Chelated with taurine. Emerging evidence for cardiovascular benefit. Taurine component may support cardiac function independently.'] | Standard | Check label |
4 Common questions
Which form of magnesium is best? ▼
It depends on the indication. Magnesium glycinate is preferred for deficiency correction and sleep support due to superior bioavailability and minimal GI side effects. Magnesium citrate is effective and affordable but may cause loose stools. Magnesium oxide has poor absorption (approximately 4%) and is primarily useful as a laxative. Magnesium taurate is emerging as a preferred form for cardiovascular support [2].
Can magnesium help with sleep? ▼
Magnesium glycinate and taurate may improve sleep quality, particularly in individuals with low magnesium status. Magnesium modulates GABA receptors, the primary inhibitory neurotransmitter system. Evidence is strongest in older adults with insomnia. Take 200-400 mg in the evening, 30-60 minutes before bedtime [2].
How do I know if I am magnesium deficient? ▼
Serum magnesium testing has poor sensitivity because only 1% of body magnesium is in the blood. Early symptoms include muscle cramps, fatigue, irritability, and poor sleep. Advanced deficiency causes numbness, tingling, cardiac arrhythmias, and seizures. Red blood cell magnesium or ionized magnesium testing provides better assessment [1].
Does magnesium interact with medications? ▼
Magnesium reduces absorption of bisphosphonates (alendronate), antibiotics (tetracyclines, fluoroquinolones), and levothyroxine. Separate these medications from magnesium supplements by at least 2 hours. Magnesium may potentiate the effects of muscle relaxants and calcium channel blockers [1].
5 Clinical evidence
Strong
Eclampsia and preeclampsia treatment: intravenous magnesium sulfate is the gold-standard treatment, reducing eclamptic seizure recurrence by 52% versus diazepam (Magpie Trial, n = 10,141) [3]. Blood pressure reduction: meta-analysis of 34 trials found supplementation with 368 mg/day reduced systolic blood pressure by 2.0 mmHg and diastolic by 1.8 mmHg [4]. HIGH
Moderate
Type 2 diabetes risk reduction: 100 mg/day increase in dietary magnesium associated with 15% lower T2DM risk in a meta-analysis of prospective studies [1]. Migraine prevention: 600 mg/day of magnesium citrate reduced migraine frequency by 41.6% in a randomized trial [1]. Sleep quality improvement: glycinate and taurate forms may improve subjective sleep quality in older adults with insomnia [2]. MODERATE
Insufficient
6 Safety, toxicity & adverse events
Absolute contraindications
✕ Severe renal failure (GFR <30 mL/min) — impaired magnesium excretion causes hypermagnesemia
Relative
⚠ Myasthenia gravis — magnesium inhibits acetylcholine release at neuromuscular junction
⚠ Heart block (2nd/3rd degree) — magnesium slows AV conduction
⚠ Concurrent aminoglycoside antibiotics — additive neuromuscular blockade
🚩 Red flags
● Refractory hypokalemia — always check magnesium; Mg depletion impairs renal potassium conservation [3]
● Refractory hypocalcemia — Mg is required for PTH secretion and action; correct Mg first [3]
● New arrhythmias (especially torsades de pointes) in patient on diuretics — check Mg urgently [3]
● Muscle cramps + PPI + diuretic combination — triple risk for hypomagnesemia [5]
● Epsom salt bath ingestion in children or renal patients — hypermagnesemia risk [3]
7 Interactions
Drug interactions
Bisphosphonates (alendronate, risedronate, zoledronate) Major
Mechanism: Divalent cation chelation forms insoluble complex, reducing bisphosphonate bioavailability by up to 85% [4].
Fluoroquinolones (ciprofloxacin, levofloxacin, moxifloxacin) Major
Mechanism: Mg²⁺ chelates the 4-oxo-3-carboxylic acid group of fluoroquinolones, reducing absorption by 30–50% [4].
Proton pump inhibitors (omeprazole, esomeprazole) Moderate
Mechanism: PPI-induced hypomagnesemia via impaired intestinal TRPM6/7 channel-mediated active absorption. FDA safety warning (2011) [5].
Loop diuretics (furosemide) Moderate
Mechanism: Inhibition of Na-K-2Cl cotransporter in thick ascending limb reduces paracellular magnesium reabsorption [3].
Digoxin Moderate
Mechanism: Hypomagnesemia increases myocardial sensitivity to digoxin by enhancing Na/K-ATPase inhibition. Risk of fatal arrhythmias [3].
8 Laboratory monitoring
Serum magnesium Primary
RBC magnesium Secondary
24-hour urine magnesium Secondary
9 Regulatory
United States (FDA): Dietary supplement. No prescription required. FDA-approved IV MgSO4 for eclampsia and torsades de pointes. Epsom salt (MgSO4) sold as OTC soaking product and laxative [1].
European Union (EFSA): Authorized health claims for electrolyte balance, energy metabolism, nervous system function, muscle function, protein synthesis, bone maintenance, and reduction of tiredness [6]. Supplement limits vary by member state (typically 250–375 mg).
Japan (MHLW): Dietary supplement with established nutrient function claims. Popular as bath salt (onsen culture) and in traditional remedies [1].
Codex Alimentarius (WHO/FAO): NRV of 300 mg/day. IV MgSO4 on WHO Model List of Essential Medicines for eclampsia management [1].
10 US supplement products
6,084
on-market products containing Magnesium (NIH DSLD)
Brands carrying Magnesium (1067)
Click a brand to see its Magnesium products.
11 Frequently paired with
12 References (4)
[1]National Institutes of Health, Office of Dietary Supplements. Magnesium — Fact sheet for health professionals. Updated 2024. ods.od.nih.gov REVIEW Accessed: 2026-05-29
[2]DiNicolantonio JJ, O'Keefe JH, Wilson W. Subclinical magnesium deficiency: a principal driver of cardiovascular disease and a public health crisis. Open Heart. 2018;5(1):e000668. doi:10.1136/openhrt-2017-000668 REVIEW Accessed: 2026-05-29
[3]Altman D, et al. Do women with pre-eclampsia, and their babies, benefit from magnesium sulphate? The Magpie Trial. Lancet. 2002;359(9321):1877-1890. doi:10.1016/S0140-6736(02)08778-0 RCT Accessed: 2026-05-29
[4]Zhang X, et al. Effects of magnesium supplementation on blood pressure: a meta-analysis of randomized double-blind placebo-controlled trials. Hypertension. 2016;68(2):324-333. doi:10.1161/HYPERTENSIONAHA.116.07664 META-ANALYSIS Accessed: 2026-05-29
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14 Cite this page
Vancouver: Pkhakadze G. Magnesium — safety profile [Internet]. Tbilisi: PHIG; 2026 [cited 2026 Jun 02]. Available from: https://supplement.ge/ingredients/magnesium/
APA 7th: Pkhakadze, G. (2026). Magnesium — Safety profile. Public Health Institute of Georgia. https://supplement.ge/ingredients/magnesium/
📋 Editorial information
Author: Prof. G. Pkhakadze, MD, MPH, PhD
Institution: Public Health Institute of Georgia (PHIG)
Affiliation: David Tvildiani Medical University (DTMU)
First published: January 2026
Last reviewed: 2026-05-29
Next review: December 2026
References: 4 cited sources
COI: SupplementIndex receives no funding from supplement manufacturers. All content independently authored by PHIG.
Process: Systematic literature review
📄 License & reuse
Published under Creative Commons Attribution 4.0 International (CC BY 4.0). You may share and adapt for any purpose with attribution.
Pkhakadze G. "Magnesium — Safety Profile." SupplementIndex, PHIG, 2026. https://supplement.ge/ingredients/magnesium/ CC BY 4.0.
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Educational and public health purposes. CC BY 4.0. Consult your healthcare provider before starting any supplement. Corrections: info@accreditation.ge. Publisher: PHIG