Remedy · nutrient
Magnesium
Also: Mg
An essential mineral widely recommended for cramps — though the best evidence is unconvincing.
Evidence by condition
Each grade reflects the research for Magnesium and that condition specifically.
- BMigraine
About 600 mg/day modestly reduces migraine attack frequency; evidence is mixed but supportive.
2 citation s
- Prophylaxis of migraine with oral magnesium: a prospective, multi-center, placebo-controlled, double-blind randomized study Randomized trial 1996 · n=81 · Cephalalgia · PMID 8792038 · DOI 10.1046/j.1468-2982.1996.1604257.x
- Magnesium — Health Professional Fact Sheet NIH ODS · accessed 2026-06-21
- Prophylaxis of migraine with oral magnesium: a prospective, multi-center, placebo-controlled, double-blind randomized study
- BHigh blood pressure
Small blood-pressure reduction, larger in people on BP medication or who are magnesium-deficient.
2 citation s
- Magnesium Supplementation and Blood Pressure: A Systematic Review and Meta-Analysis of Randomized Controlled Trials Meta-analysis 2025 · n=2,709 · Hypertension · DOI 10.1161/HYPERTENSIONAHA.125.25129
- Complementary Health Approaches for Hypertension: What the Science Says NCCIH · accessed 2026-06-21
- Magnesium Supplementation and Blood Pressure: A Systematic Review and Meta-Analysis of Randomized Controlled Trials
- CInsomnia
May modestly shorten time to fall asleep in older adults; low-certainty evidence.
2 citation s
- Oral magnesium supplementation for insomnia in older adults: a systematic review and meta-analysis Meta-analysis 2021 · n=151 · BMC Complementary Medicine and Therapies · PMID 33865376 · DOI 10.1186/s12906-021-03297-z
- Magnesium — Health Professional Fact Sheet NIH ODS · accessed 2026-06-21
- Oral magnesium supplementation for insomnia in older adults: a systematic review and meta-analysis
- CType 2 diabetes
Higher dietary magnesium intake is linked to a lower risk of developing type 2 diabetes in large observational studies; this is a risk association, not proof that supplements treat established diabetes.
2 citation s
- Magnesium intake and risk of type 2 diabetes: meta-analysis of prospective cohort studies Meta-analysis 2011 · n=5,36,318 · Diabetes Care · PMID 21868780
- Magnesium — Health Professional Fact Sheet NIH ODS · accessed 2026-06-21
- Magnesium intake and risk of type 2 diabetes: meta-analysis of prospective cohort studies
- CPremenstrual syndrome
Small trials suggest magnesium modestly eases PMS mood and fluid-retention symptoms, sometimes only after the first cycle.
2 citation s
- Oral magnesium successfully relieves premenstrual mood changes Randomized trial 1991 · n=32 · Obstetrics & Gynecology · PMID 2067759
- Magnesium — Health Professional Fact Sheet NIH ODS · accessed 2026-06-21
- Oral magnesium successfully relieves premenstrual mood changes
- DMuscle cramps
For idiopathic or nocturnal leg cramps in older adults, magnesium is probably no better than placebo; pregnancy-related cramp data are inconsistent.
2 citation s
- Magnesium for skeletal muscle cramps Systematic review 2020 · n=735 · Cochrane Database of Systematic Reviews · DOI 10.1002/14651858.CD009402.pub3
- Magnesium — Health Professional Fact Sheet NIH ODS · accessed 2026-06-21
- Magnesium for skeletal muscle cramps
- DRestless legs syndrome
Only small open-label/uncontrolled studies support magnesium for restless legs; no placebo-controlled trial confirms a benefit.
1 citation
- Magnesium citrate monotherapy improves restless legs syndrome symptoms: an open-label pilot study Study 2024 · n=12 · Journal of Clinical Sleep Medicine · PMID 38738598 · DOI 10.5664/jcsm.11206
- Magnesium citrate monotherapy improves restless legs syndrome symptoms: an open-label pilot study
- DFibromyalgia
A small RCT missed its primary endpoint but found a modest pain reduction; weak, mixed evidence.
1 citation
- Short-term magnesium therapy alleviates moderate stress in patients with fibromyalgia: a randomized double-blind clinical trial Randomized trial 2022 · n=75 · Nutrients · PMID 35631229 · DOI 10.3390/nu14102088
- Short-term magnesium therapy alleviates moderate stress in patients with fibromyalgia: a randomized double-blind clinical trial
Magnesium is essential in the diet, and correcting a true deficiency matters — but taking extra for ordinary leg cramps is not supported by the best trials.