tuneTypical Dose
300 mg
Mineral
Magnesium
Magnesium (Mg, element 12)
Evidence TierAWADA NOT PROHIBITED
watchEffect Window
Acute relaxation within hours. Deficiency correction over 2-4 weeks.
check_circleCompliance
WADA NOT PROHIBITED
Overview
Clinical Summary
Magnesium is an essential mineral involved in neuromuscular function and hundreds of enzymes. It is used to correct low intake and to support sleep, cramps, migraine prevention, and blood pressure control.
Restoring low magnesium status can reduce cramps and fatigue and support normal cardiac rhythm. Trials show modest blood pressure reductions, with larger effects in hypertension or low magnesium status, and reduced migraine frequency in some people. Minority evidence suggests improved sleep quality and insulin sensitivity, particularly with low baseline status. Gastrointestinal tolerance varies by form and dose, which can determine usable intake.
Cofactor for >300 enzymatic reactions. NMDA receptor antagonist reducing neuronal excitability. Regulates GABA, melatonin, and cortisol.
Outcomes
What This Is Expected To Influence
Primary Outcomes
- Deficiency correction
- Muscle cramp relief
- Blood pressure reduction
Secondary Outcomes
- Sleep quality improvement
- Anxiety reduction
- Migraine frequency reduction
Safety
Contraindications and Interactions
Contraindications
- Severe renal failure
- Myasthenia gravis
- Heart block
Side effects
- Diarrhea and loose stools (dose-limiting, especially oxide/citrate forms) - Taking magnesium in divided doses may reduce diarrhea. Certain magnesium salts (e.g., magnesium gluconate, magnesium chloride) may be less likely to cause diarrhea.
- Abdominal pain and GI cramping
- Nausea at higher doses
- Bone pain
- Muscle weakness
- Itching
- Tingling
- Skin flushing
- Sweating
Interactions
- Bisphosphonates (Probable/Moderate) - Magnesium can reduce bisphosphonate absorption. Separate dosing by at least 2 hours.
- Tetracycline antibiotics (Probable/Moderate) - Magnesium can reduce tetracycline absorption. Separate dosing by at least 2 hours.
- Fluoroquinolone antibiotics (Probable/Moderate) - Magnesium can reduce fluoroquinolone absorption. Separate dosing by at least 2 hours.
- Muscle relaxants/neuromuscular blockers (Possible/Moderate) - Magnesium may potentiate neuromuscular blockade.
- Loop and thiazide diuretics (Possible/Moderate) - These can increase magnesium excretion and alter magnesium status.
- Digoxin (Probable/Moderate) - Magnesium may reduce the absorption of digoxin when administered together, leading to decreased drug levels.
- Levodopa (Probable/Moderate) - Magnesium may reduce the absorption of levodopa when administered together, leading to decreased drug levels.
- Carbidopa (Probable/Moderate) - Magnesium may reduce the absorption of levodopa when administered together, leading to decreased drug levels.
- H2-receptor antagonists (Probable/Moderate) - Magnesium may reduce H2-receptor antagonist absorption when administered together, leading to decreased drug levels.
- Vericiguat (Possible/Moderate) - Magnesium might reduce the absorption of vericiguat when administered together, leading to decreased drug levels, which could reduce the effectiveness of vericiguat.
- Gabapentin (Possible/Moderate) - Magnesium may reduce the absorption of gabapentin when administered together, leading to decreased drug levels.
- Iron (Possible/Moderate) - Magnesium may reduce the absorption of iron when administered together, potentially reducing the effectiveness of iron supplements.
- Nitrofurantoin (Possible/Moderate) - Magnesium may reduce the absorption of nitrofurantoin when administered together, leading to decreased drug levels, which could impair the effectiveness of nitrofurantoin.
Avoid if
- People with severe kidney disease
- People on dialysis without physician guidance
- People using digoxin
- People using levodopa
- People using carbidopa
- People using H2-receptor antagonists
- People using vericiguat
- People using gabapentin
- People using iron
- People using nitrofurantoin
Evidence
Study-level References
magnesium-SRC-001Meta-analysis
Sourceopen_in_newZhang X, et al. "Effects of Magnesium Supplementation on Blood Pressure: A Meta-Analysis of Randomized Double-Blind Placebo-Controlled Trials." Hypertension. 2016.
Population: Adults (Hypertensive and Normotensive)
Key findings: Magnesium supplementation results in a small but significant reduction in blood pressure.
Paper content
Magnesium supplementation results in a small but significant reduction in blood pressure.
magnesium-SRC-002Randomized, double-blind, placebo-controlled trial.
Sourceopen_in_newHausenblas HA, Lynch T, Hooper S, Shrestha A, Rosendale D, Gu J. Magnesium-L-threonate improves sleep quality and daytime functioning in adults with self-reported sleep problems: A randomized controlled trial. Sleep Med X. 2024;8:100121. doi:10.1016/j.sleepx.2024.100121. PMID:39252819.
Population: Adults aged 35 to 55 with self-assessed sleep problems.
Dose protocol: 1 g/day magnesium L-threonate for 21 days
Key findings: Randomized trial showed improved subjective sleep quality and daytime functioning, with some selected objective sleep improvements.
Notes: Form-specific evidence. Do not generalize this directly to every magnesium salt.
Paper content
This 21-day randomized placebo-controlled trial tested 1 g per day of magnesium L-threonate in 80 adults aged 35 to 55 with self-reported sleep problems. The MgT group showed significant improvements in deep sleep scores, REM sleep, and activity measures compared to placebo. Subjective improvements included better mood, energy, alertness, and productivity. The study adds a second independent RCT endpoint for MgT beyond the earlier Liu 2016 cognitive trial, supporting both sleep and daytime functioning benefits. The short duration and self-report measures are limitations.
magnesium-SRC-003Randomized, double-blind, placebo-controlled parallel trial
Sourceopen_in_newSchuster J, Cycelskij I, Lopresti AL, Hahn A. Magnesium Bisglycinate Supplementation in Healthy Adults Reporting Poor Sleep: A Randomized, Placebo-Controlled Trial. Nat Sci Sleep. 2025;17:2027-2040. doi:10.2147/NSS.S524348. PMID:40918053.
Population: Healthy adults reporting poor sleep quality.
Dose protocol: 250 mg elemental magnesium as magnesium bisglycinate daily for 28 days versus placebo.
Key findings: Form-specific RCT found a modest but statistically significant improvement in insomnia severity at week 4 versus placebo (Cohen's d = 0.2).
Notes: Useful as magnesium sleep evidence, but keep the claim narrow. This was a small-effect bisglycinate trial, not a meta-analysis and not evidence that all magnesium forms perform the same.
Paper content
This open-access parallel RCT randomized 155 adults with poor sleep to 250 mg elemental magnesium as bisglycinate or placebo for 4 weeks. The active group showed a modest but statistically significant between-group advantage on the Insomnia Severity Index, with a small effect size and no clear benefit on broader fatigue, stress, or mood questionnaires. Exploratory subgroup analyses suggested larger improvements in participants with lower baseline magnesium intake, which supports practical use in likely low-intake sleepers more than it supports a large class-wide sleep claim for magnesium glycinate in magnesium-replete adults.
magnesium-SRC-004Systematic review and meta-analysis of randomized controlled trials
Sourceopen_in_newArgeros Z, Xu X, Bhandari B, Harris K, Touyz RM, Schutte AE. Magnesium Supplementation and Blood Pressure: A Systematic Review and Meta-Analysis of Randomized Controlled Trials. Hypertension. 2025;82(11):1844-1856. doi:10.1161/HYPERTENSIONAHA.125.25129. PMID:41000008.
Population: Adults in 38 randomized trials evaluating oral magnesium supplementation and blood pressure.
Dose protocol: 82.3-637 mg elemental magnesium daily across trials, with a median dose of 365 mg for about 12 weeks.
Key findings: Updated meta-analysis found modest overall reductions in systolic and diastolic blood pressure, with larger effects in hypertension and hypomagnesemia.
Notes: Helps keep the blood-pressure claim population-specific instead of implying a universal effect.
Paper content
Updated pooled evidence supports modest blood-pressure lowering with oral magnesium, especially in people with hypertension or low magnesium status, while normotensive populations did not show a clear significant effect. The review did not identify a convincing dose-response relationship across the included range.
magnesium-SRC-005Systematic review and dose-response meta-analysis of randomized controlled trials.
Sourceopen_in_newTalandashti MK, Shahinfar H, Delgarm P, Jazayeri S. Effects of selected dietary supplements on migraine prophylaxis: a systematic review and dose-response meta-analysis of randomized controlled trials. Neurol Sci. 2025;46(2):651-670. doi:10.1007/s10072-024-07794-0. PMID:39404918.
Population: Adults with migraines across 22 included randomized controlled trials.
Dose protocol: Various magnesium forms and doses across pooled migraine-prevention RCTs.
Key findings: Dose-response meta-analysis found magnesium reduced migraine frequency by about 2.5 attacks per month, with significant reductions in severity and monthly migraine days.
Notes: Strongest migraine-specific quantitative evidence for magnesium supplementation, supporting guideline-level recommendations.
Paper content
This dose-response meta-analysis pooled 22 RCTs to evaluate dietary supplements for migraine prophylaxis. Magnesium supplementation significantly reduced migraine frequency (MD = -2.51 attacks per month), severity (MD = -0.88), and monthly migraine days (MD = -1.66). CoQ10 and vitamin D also showed significant reductions in migraine frequency. Omega-3 did not reach statistical significance. The study provides quantitative support for magnesium as a migraine-prevention supplement with a meaningful reduction in attack frequency and duration, consistent with guideline recommendations.
magnesium-SRC-006Cochrane systematic review and meta-analysis of randomized controlled trials.
Sourceopen_in_newGarrison SR, Korownyk CS, Kolber MR, et al. Magnesium for skeletal muscle cramps. Cochrane Database Syst Rev. 2020;9(9):CD009402. doi:10.1002/14651858.CD009402.pub3. PMID:32956536.
Population: 735 participants across 11 trials, including adults with idiopathic cramps (mean age 61-69 years), pregnant women with leg cramps, and patients with liver cirrhosis.
Dose protocol: Various oral magnesium forms across 11 RCTs (735 participants).
Key findings: Cochrane review found small, non-statistically-significant reductions in cramp frequency for idiopathic cramps. Evidence does not support routine use for muscle cramps in replete individuals.
Notes: Important for honest framing. Magnesium may help cramps driven by deficiency but is not a reliable cramp remedy in people with adequate status.
Paper content
This Cochrane review of 11 RCTs (735 participants) found that magnesium supplementation produced small, non-statistically-significant reductions in cramp frequency for adults with idiopathic cramps compared to placebo. Results were similarly inconclusive for cramp intensity and duration. For pregnancy-associated leg cramps, evidence was also insufficient to confirm benefit. Minor adverse events (mainly GI symptoms) were more common with magnesium. The review provides an important corrective to the popular belief that magnesium reliably prevents muscle cramps in replete individuals, while leaving open the possibility of benefit in people with genuinely low magnesium status.