NutriDex

The Supplement Research Compendium
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Magnesium

An essential mineral in 300+ enzymatic reactions.

Moderate evidence 🧂Mineral🌙Sleep & Mood

✚ Updated · How we grade evidence

Evidence tier
Moderate
Research weight
Citations
20 verified / 20
Classification
Mineral
❝
What the evidence says. Several controlled trials; effects real but modest or context-dependent.

What is Magnesium?

Magnesium is a mineral used for sleep quality. NutriDex grades the human evidence as Moderate. Magnesium is a cofactor in energy metabolism, muscle and nerve function, and DNA synthesis. Deficiency is common with modern diets. Supplementation modestly lowers blood pressure, may reduce migraine frequency, and improves subjective sleep in deficient or older individuals. L-threonate is marketed for cognition but human data are thin. Effects are most pronounced when correcting a deficiency.

Purported Benefits

✓Sleep quality
✓Muscle relaxation
✓Blood pressure
✓Migraine prevention

Evidence by outcome

The same supplement can be well-proven for one use and unproven for another — here is the human evidence graded outcome by outcome.

OutcomeEvidenceEffectStudies
Blood pressureMeta-analyses show modest BP drops (~2-3 mmHg), larger in medicated hypertensives and hypomagnesemia; none in normotensives. Moderate ↑ benefit · small 3
Sleep qualitySmall RCTs and reviews show modest sleep-onset/quality gains, mainly in older or low-magnesium adults; low-quality evidence. Preliminary ↑ benefit · small 3
Migraine preventionGuidelines rate it 'probably effective'; meta-analysis shows fewer attacks (MD -2.51) and migraine days. Moderate ↑ benefit · moderate 2
Glycemic control (type 2 diabetes)Dose-response meta-analyses show fasting-glucose reduction and HbA1c signals, but evidence deemed insufficient for guidelines. Mixed ↑ benefit · small 2
Depressive symptomsOne small meta-analysis (7 RCTs, n=325) found a large effect (SMD -0.92) but limited, low-powered evidence. Preliminary ↑ benefit · moderate 1
Nocturnal leg crampsEvidence review concluded magnesium does not reduce idiopathic or pregnancy leg cramps over short courses. Moderate — no effect · negligible 1

Dosing & Compounds

Typical Dose
200–400 mg elemental/day. Glycinate & citrate absorb best; oxide is poorly absorbed.
Active Compounds
Mg glycinateMg citrateMg L-threonateMg oxide

Safety & Cautions

Safe. Excess causes diarrhea (citrate/oxide). Caution in kidney disease. Educational only — always check with your doctor or pharmacist before combining Magnesium with any medicine.

Magnesium drug interactions

Known or theoretical interactions between Magnesium and common medications — educational, not exhaustive. Always check with your doctor or pharmacist before combining Magnesium with any medicine.

Caution
Quinolone/tetracycline antibiotics, bisphosphonates
Magnesium binds these drugs and cuts absorption; separate dosing by several hours.
Divalent magnesium forms insoluble chelates with quinolones, tetracyclines, bisphosphonates, levothyroxine. NIH ODS — Magnesium

Key Studies ★ 20 studies

Meta-analysis Rosanoff 2025 (meta-analysis, Hypertension) ✓ PubMed
In 38 RCTs (n=2,709), magnesium reduced SBP by -2.81 mmHg and DBP by -2.05 mmHg, with larger effects in medicated hypertensives (-7.68 mmHg SBP) and those with hypomagnesemia, but no effect in normotensives.
Meta-analysis Asbaghi 2024 (umbrella meta-analysis) ✓ PubMed
Umbrella meta-analysis of 10 reviews (8,610 participants) found magnesium significantly lowered SBP (-1.25 mmHg) and DBP (-1.40 mmHg), with stronger reductions at >=400 mg/day for >=12 weeks.
Meta-analysis Moabedi 2023 (meta-analysis, Front Psychiatry) ✓ Full text
Meta-analysis of 7 RCTs (n=325) in adults with depressive disorder found magnesium supplementation significantly reduced depression scores (SMD -0.92; 95% CI -1.44 to -0.40).
Meta-analysis Hajhashemi 2025 (dose-response meta-analysis, Neurol Sci) ✓ PubMed
In a meta-analysis of RCTs on migraine prophylaxis, magnesium reduced migraine attacks (MD -2.51), severity (MD -0.88), and monthly migraine days (MD -1.66) versus control.
Systematic review FPIN/AFP 2023 (evidence review) ✓ Source
Clinical inquiry summarizing systematic-review/Cochrane evidence concluded magnesium does not reduce idiopathic or pregnancy-related nocturnal leg cramps over short courses (<60 days).
Meta-analysis Vink 2025 (meta-analysis, SQU Med J) ✓ Full text
Meta-analysis of 23 RCTs (n=1,345) in type 2 diabetes found magnesium significantly lowered fasting glucose (WMD -0.58) but no significant overall HbA1c reduction, with benefit concentrated in longer (>=6 month) regimens and older adults.
systematic review/meta-analysis Madireddy 2024 (systematic review & meta-analysis, Adv Nutr) ✓ PubMed
Systematic review/meta-analysis (3 RCTs + 12 cohorts) found Mg supplement RCTs inconclusive, but cohorts showed a U-shaped serum magnesium association with dementia/cognitive impairment (optimum ~0.85 mmol/L), with higher risk at <0.75 mmol/L (HR 1.43) and >0.95 mmol/L (HR 1.30).
Systematic review Rawji 2024 (Cureus) ✓ Full text
Systematic review of 15 interventional trials found 5 of 8 sleep studies showed improvement (PSQI-based), with higher doses (243-729 mg) more effective; authors conclude magnesium is likely useful for mild insomnia, especially with low baseline magnesium status.
Meta-analysis Veronese 2022 (dose-response meta-analysis, Br J Nutr) ✓ PubMed
Dose-response meta-analysis of 18 RCTs in type 2 diabetes found oral magnesium (e.g., ~500 mg/day) reduced HbA1c by about -0.73% and improved fasting glucose, though evidence was deemed insufficient for clinical guidelines.
systematic review/meta-analysis Groenendijk 2022 (systematic review & meta-analysis, Bone) ✓ PubMed
Systematic review/meta-analysis of 12 studies in older adults (>=60 y) found a significant positive association between magnesium intake and hip bone mineral density (pooled beta 0.03; 95% CI 0.01-0.06), though data were too limited to link magnesium to fracture risk.
dose-response meta-analysis Bagheri 2021 (dose-response meta-analysis, Adv Nutr) ✓ PubMed
Dose-response meta-analysis of 19 prospective cohorts (1,168,756 participants) found each 100 mg/day increase in dietary magnesium was associated with 6% lower all-cause mortality (RR 0.94) and 5% lower cancer mortality (RR 0.95), with no significant association for supplemental/total magnesium or CVD mortality.
Meta-analysis Mah 2021 (BMC Complement Med Ther) ✓ PubMed
Meta-analysis of 3 RCTs (n=151 older adults) found magnesium reduced sleep onset latency by 17.36 min vs placebo (95% CI -27.27 to -7.44, p=0.0006); total sleep time gain of 16.06 min was not significant, with low/very-low quality evidence.
Meta-analysis Zhang 2016 meta-analysis ✓ PubMed
Supplementation lowered BP, especially in deficient subjects.
Meta-analysis Fang et al. 2016 (BMC Medicine) ✓ PubMed
Dose-response meta-analysis of 40 prospective cohorts (>1 million participants): each 100 mg/day increment in dietary magnesium was associated with 22% lower heart failure risk, 7% lower stroke risk, 19% lower type 2 diabetes risk, and 10% lower all-cause mortality.
Meta-analysis Hruby/Schwingshackl-type dose-response (Zhao et al. 2016, Nutrients) ✓ PubMed
Meta-regression of 25 prospective cohorts (637,922 individuals; 26,828 T2D cases): per 100 mg/day increment in dietary magnesium, type 2 diabetes risk fell ~8-13% after adjustment; overall lowest-vs-highest intake reduced T2D risk by 17%.
Meta-analysis Dong et al. 2011 (Diabetes Care) ✓ PubMed
Meta-analysis of 13 prospective cohorts (536,318 participants; 24,516 cases) found an inverse association between magnesium intake and type 2 diabetes (RR 0.78, 95% CI 0.73-0.84); per 100 mg/day increment, summary RR was 0.86 (95% CI 0.82-0.89).
RCT Hausenblas 2024 ✓ PubMed
In 80 adults (35-55y) with self-reported sleep problems, 1 g/day magnesium-L-threonate for 21 days significantly improved deep sleep, REM sleep, light sleep time, and awakening behavior vs placebo (p<0.05), and preserved sleep quality while placebo declined.
RCT Frontiers in Nutrition 2026 ✓ Full text
In 100 adults, 2 g/day magnesium-L-threonate (Magtein) for 6 weeks produced greater improvement in PROMIS sleep-related impairment than placebo (p=0.043), with a significant benefit in those with more severe baseline sleep disturbance (p=0.031).
Study Abbasi 2012 ✓ PubMed
Improved insomnia severity and sleep efficiency in older adults.
Study AAN/AHS guidelines ✓ Source
Magnesium rated 'probably effective' for migraine prevention.
20 sources cited · 20 verified Search all studies on PubMed ↗

Common questions about Magnesium

What is Magnesium used for?

Magnesium is most often taken for Sleep quality, Muscle relaxation, Blood pressure, Migraine prevention. An essential mineral in 300+ enzymatic reactions.

Does Magnesium work — what does the evidence say?

Moderate evidence. Several controlled trials; effects real but modest or context-dependent. Magnesium is a cofactor in energy metabolism, muscle and nerve function, and DNA synthesis. Deficiency is common with modern diets. Supplementation modestly lowers blood pressure, may reduce migraine frequency, and improves subjective sleep in deficient or older individuals. L-threonate is marketed for cognition but human data are thin. Effects are most pronounced when correcting a deficiency.

What is the typical dose of Magnesium?

200–400 mg elemental/day. Glycinate & citrate absorb best; oxide is poorly absorbed.

Is Magnesium safe? Any cautions or side effects?

Safe. Excess causes diarrhea (citrate/oxide). Caution in kidney disease.

How many studies support Magnesium?

NutriDex cites 20 sources for Magnesium, graded "Moderate".

Does Magnesium interact with any medications?

Yes — known or theoretical interactions include: Certain antibiotics (quinolones, tetracyclines) (caution). This is educational and not exhaustive; always check with your doctor or pharmacist before combining Magnesium with any medicine.

Cite this page
APA

Peh, D. (2026). Magnesium: Benefits, Dosage, Side Effects & Evidence. NutriDex — The Supplement Research Compendium. Retrieved 26 Jun 2026, from https://nutridex.info/s/magnesium

BibTeX
@misc{nutridex_magnesium,
  author       = {Peh, Daryl},
  title        = {Magnesium: Benefits, Dosage, Side Effects \& Evidence},
  year         = {2026},
  howpublished = {NutriDex --- The Supplement Research Compendium},
  url          = {https://nutridex.info/s/magnesium},
  note         = {Reviewed by Dr Daryl Peh, MBBS Singapore, MMed FM. Accessed 2026-06-26}
}

For medical claims, citing the underlying primary studies linked above is preferred. NutriDex is an educational reference, not medical advice.

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