Does magnesium help with anxiety?

Possibly a little, in people who are mildly anxious or stressed, and nobody has measured how much. A systematic review of 18 studies found that magnesium eased self-rated anxiety in 4 of 8 trials in mildly anxious people and 4 of 7 in women with premenstrual syndrome, and its authors rated the evidence quality as poor. In that review, every positive trial in anxious people gave magnesium together with vitamin B6 or herbal extracts. No meta-analysis has pooled the trials into a single effect.

Unsettled. The trials are small and mostly short. They count positive results instead of measuring a size, and the placebo groups improved clearly in all three placebo-controlled trials in mildly anxious adults. The largest trial, in 264 stressed adults, had no placebo arm at all. That combination leaves the question open, and the psychiatric guideline we found recommends no supplement other than N-acetylcysteine for any anxiety-related disorder.

What the trials found

The two reviews

The 2017 review searched to May 2016 and found 18 studies in people vulnerable to anxiety. Besides the counts above, 1 of 2 studies in people with mild high blood pressure was positive, and the one postpartum trial found no effect on anxiety after childbirth. Three of the positive studies in anxious people were unpublished, and one relied on a post hoc subsample of 15. The reviewers also noted that all of the studies with a placebo showed significant placebo effects, without giving their size.

A 2024 review searched PubMed only, to July 2023, and found 7 interventional studies with an anxiety outcome. Five were positive. The clearly negative trial gave 64.6 mg of elemental magnesium, and the largest falls came at 300 mg a day, mostly as magnesium oxide, over 5 days to 6 months. The reviewers read this as a sign that higher doses work better. That is a pattern across different trials in different people, and 4 of the 15 studies in the wider review were not randomized.

An older review from 2010, of 24 studies in 2,619 participants, judged magnesium-containing supplements promising and not yet ready to recommend. Magnesium there was studied only in combinations.

The largest trial

In an 8-week randomized trial of 264 healthy adults with high stress scores and blood magnesium of 0.45 to 0.85 mmol/L, which the trial counted as low, 300 mg of magnesium a day lowered stress scores by 42.4 percent from baseline. Adding 30 mg of vitamin B6 gave 44.9 percent, and the two arms did not differ. The trial was single-blind with no placebo group, and it was sponsored by the manufacturer, so the fall cannot be credited to magnesium. A later post hoc analysis of the same trial found anxiety scores fell by 5.86 points in the first 4 weeks (95% CI 5.04 to 6.67), again with nothing to compare against.

In an open-label crossover trial in US primary care, 126 adults with mild to moderate depression took 248 mg of magnesium a day as magnesium chloride for 6 weeks. Their anxiety scores on the GAD-7 scale improved by a net 4.5 points (95% CI 2.4 to 6.6), with 112 analyzed. Anxiety was a secondary outcome in people recruited for depression, and everyone knew what they were taking.

Premenstrual anxiety

Unsettled. Whether magnesium helps the anxiety and mood symptoms of premenstrual syndrome is not settled. A 2025 review of 31 randomized trials in 3,254 women found insufficient evidence for magnesium, although the 2017 review counted 4 of 7 PMS studies as positive. Only one of the trials in the 2025 review was at low risk of bias, and it gives no pooled numbers.

Who should be careful

Side effects in the anxiety and sleep trials were mild when present, most often more frequent bowel movements, across 15 small, short trials that could not detect rare harms. In the 264-person trial, diarrhea was the most common treatment-related side effect, in 10 of 132 people (7.6 percent) on magnesium alone and 6 of 132 (4.5 percent) with vitamin B6. Without a placebo arm the background rate is unknown.

Not for everyone. The NIH sets the upper limit for magnesium from supplements and medicines at 350 mg a day for adults, and 65 to 350 mg for children and teenagers by age. Magnesium from food does not count. The 300 mg doses in the anxiety trials sit just under the adult limit, so a child's dose is a different question. High doses often cause diarrhea, nausea and cramps, and very high doses can be toxic, typically at laxative or antacid doses above 5,000 mg a day or when kidney function is impaired.

Magnesium binds tetracycline and quinolone antibiotics, such as doxycycline and ciprofloxacin. The NIH advises taking those antibiotics at least 2 hours before or 4 to 6 hours after a magnesium supplement.

What expert bodies say

A 2022 taskforce of 31 experts from the World Federation of Societies of Biological Psychiatry and the Canadian Network for Mood and Anxiety Treatments found no nutraceutical other than N-acetylcysteine with enough evidence to recommend for any anxiety-related disorder. Magnesium was not recommended as a treatment for depression on its own. The taskforce counted only its highest grade of evidence, so the missing recommendation reflects how thin the trials are.

How we searched

What would change this answer

• A placebo-controlled trial of magnesium alone, without vitamin B6 or herbs, in adults with a diagnosed anxiety disorder. None was found, and none is registered in the slice we searched.
• A meta-analysis that pools the existing trials into an effect size with an interval. We found none from 2017 to 2026.
• A trial that compares doses directly. The idea that higher doses work better rests on comparing different trials in different people.

How much magnesium you need and where it comes from in food is in the magnesium guide. Whether it helps you sleep has its own evidence page.

Sources

1. ev-mganx-01 · Meta-analysis or systematic review · systematic review of intervention studies, no meta-analysis · n = 18 studies
   Four/eight studies in anxious samples, four/seven studies in PMS samples, and one/two studies in hypertensive samples reported positive effects of Mg on subjective anxiety outcomes.
   
   Who: people vulnerable to anxiety: mildly anxious adults, women with premenstrual syndrome, postpartum women, people with mild hypertension
   Effect: positive anxiety outcome in 4/8 studies in anxious samples, 4/7 in PMS, 1/2 in hypertension; no pooled effect size
   Certainty: authors rate the evidence quality as poor; counts of positive studies, not effect sizes; search to May 2016
   Nutrients, 2017 · checked 2026-10-06 · we read the abstract
2. ev-mganx-02 · Meta-analysis or systematic review · systematic review of intervention studies · n = 8 studies
   Those studies which reported positive effects all administered Mg in combination with additional ingredients (e.g., vitamin B6, extract of Hawthorn and California poppy).
   
   Who: adults with mild to moderate anxiety, mostly HAM-A 10 to 30, in 8 studies
   Effect: 4 of 8 positive, all of them combination products (Mg lactate plus B6, Mg plus hawthorn and California poppy)
   Certainty: three of the positive studies were unpublished; one relied on a post hoc subsample of 15
   Nutrients, 2017 · checked 2026-10-06 · we read the fulltext
3. ev-mganx-03 · Meta-analysis or systematic review · systematic review of intervention studies · n = 3 placebo-controlled studies
   All of the studies which included a placebo demonstrated significant placebo effects.
   
   Who: adults with mild to moderate anxiety in placebo-controlled trials
   Effect: significant placebo response in all placebo-controlled studies; Mg effect reported above placebo in those trials
   Certainty: qualitative statement by the reviewers; no numbers for the size of the placebo response
   Nutrients, 2017 · checked 2026-10-06 · we read the fulltext
4. ev-mganx-04 · Meta-analysis or systematic review · systematic review of interventional trials, mostly RCTs, no meta-analysis · n = 7 studies
   However, higher doses of magnesium appear to be more effective in addressing anxiety and sleep disturbances, as all studies with negative results used low comparative dosages of the mineral in their treatment interventions.
   
   Who: 7 interventional studies with anxiety outcomes: pediatric migraine, premenstrual and postpartum women, stressed adults, heart surgery patients, generalized anxiety and adjustment disorder
   Effect: 5 of 7 studies positive; the clearly negative trial gave 64.6 mg elemental magnesium; largest reductions with 300 mg elemental magnesium a day; mostly magnesium oxide, 5 days to 6 months
   Certainty: PubMed only, searched to July 2023; 4 of 15 included studies not randomized; vote counting, no pooled effect
   Cureus · checked 2026-10-06 · we read the fulltext
5. ev-mganx-05 · Meta-analysis or systematic review · systematic review of RCTs and open-label studies · n = 2619
   Magnesium-containing supplements and other herbal combinations may hold promise, but more research is needed before these products can be recommended to patients.
   
   Who: 2619 participants, mostly with an anxiety disorder or depression, in 21 RCTs and 3 open-label studies of supplements and herbs
   Effect: no magnesium-specific effect size; heterogeneity prevented meta-analysis
   Certainty: older review; magnesium studied only in combinations
   Nutr J, 2010 · checked 2026-10-06 · we read the abstract
6. ev-mganx-06 · Meta-analysis or systematic review · systematic review of RCTs, narrative synthesis · n = 3254
   There was insufficient evidence to support the effects of vitamin B1, vitamin D, whole-grain carbohydrates, soy isoflavones, dietary fatty acids, magnesium, multivitamin supplementation, or PMS-specific diets.
   
   Who: women of reproductive age, 15 to 50 years, with premenstrual syndrome, 31 RCTs
   Effect: insufficient evidence for magnesium on psychological PMS symptoms; only 1 of the included trials at low risk of bias
   Certainty: narrative review, no pooled numbers; Cochrane RoB 2 used
   Nutr Rev, 2025 · checked 2026-10-06 · we read the abstract
7. ev-mganx-07 · Meta-analysis or systematic review · systematic review of intervention studies · n = 1 study
   Mg had no effect on postpartum anxiety.
   
   Who: postpartum women, one study within an 18-study review
   Effect: no effect on postpartum anxiety
   Certainty: single trial behind the statement; Rawji 2024 adds that it used only 64.6 mg elemental magnesium
   Nutrients, 2017 · checked 2026-10-06 · we read the abstract
8. ev-mganx-08 · Randomized controlled trial(s) · randomized single-blind trial, two active arms · n = 264
   In the modified intention-to-treat analysis (N = 264 subjects), both treatment arms substantially reduced DASS-42 stress subscale score from baseline to Week 8 (Mg-vitamin B6, 44.9%; Mg 42.4%); no statistical difference between arms was observed (p>0.05).
   
   Who: healthy adults with DASS-42 stress score above 18 and serum magnesium 0.45 to 0.85 mmol/L, magnesium 300 mg a day with or without vitamin B6 30 mg, 8 weeks
   Effect: DASS-42 stress down 42.4% (Mg) and 44.9% (Mg plus B6) from baseline, no difference between arms
   Certainty: no placebo group, so the fall in stress cannot be credited to magnesium; manufacturer-sponsored
   PLoS One, 2018 · checked 2026-10-06 · we read the abstract
9. ev-mganx-09 · Randomized controlled trial(s) · post hoc secondary analysis of a randomized trial with two active arms · n = 264
   Greatest improvement in mean anxiety score occurred in the first 4 weeks of treatment; the overall group mean score decreased from baseline by −5.86 (95% CI −6.67; −5.04).
   
   Who: stressed healthy adults with low magnesemia, magnesium 300 mg a day with or without vitamin B6, 8 weeks
   Effect: DASS-42 anxiety change from baseline at week 4 -5.86 (95% CI -6.67 to -5.04), whole ITT population; no difference between Mg and Mg plus B6
   Certainty: post hoc analysis, no placebo arm; within-group change only
   Stress Health, 2021 · checked 2026-10-06 · we read the fulltext
10. ev-mganx-10 · Randomized controlled trial(s) · open-label randomized crossover trial · n = 126
    Consumption of magnesium chloride for 6 weeks resulted in a clinically significant net improvement in PHQ-9 scores of -6.0 points (CI -7.9, -4.2; P<0.001) and net improvement in Generalized Anxiety Disorders-7 scores of -4.5 points (CI -6.6, -2.4; P<0.001).
    
    Who: 126 adults (mean age 52, 38% male) with PHQ-9 5 to 19 in US primary care, magnesium chloride 248 mg elemental magnesium a day for 6 weeks vs 6 weeks of no treatment
    Effect: GAD-7 net change -4.5 points (95% CI -6.6 to -2.4); PHQ-9 -6.0 (-7.9 to -4.2); 112 analyzed
    Certainty: open label, no placebo; anxiety was a secondary outcome in people recruited for depression
    PLoS One, 2017 · checked 2026-10-06 · we read the abstract
11. ev-mganx-11 · Position of an expert body · clinical practice guideline based on meta-reviews · n = —
    NAC was weakly recommended (+) in the treatment of OCD-related disorders; however, no other nutraceutical had sufficient evidence in any anxiety-related disorder.
    
    Who: clinicians treating psychiatric disorders; evidence graded from meta-analyses and pairs of RCTs
    Effect: magnesium not recommended (-) as monotherapy for depression; no supplement except NAC (for OCD-related disorders) recommended in anxiety-related disorders
    Certainty: 2022 guideline; considers only grade A evidence, so absence of a recommendation reflects thin trial data
    World J Biol Psychiatry, 2022 · checked 2026-10-06 · we read the abstract
12. ev-mganx-12 · Meta-analysis or systematic review · systematic review of interventional trials · n = 15 studies
    Adverse events in the included studies were mild if present - most commonly increased bowel movements, a well-known side effect of magnesium administration.
    
    Who: 15 interventional trials of supplemental magnesium for anxiety or sleep
    Effect: adverse events mild if present; most common increased bowel movements
    Certainty: trials were small and short; rare harms could not be detected
    Cureus · checked 2026-10-06 · we read the fulltext
13. ev-mganx-13 · Randomized controlled trial(s) · randomized single-blind trial · n = 264
    The most common treatment-related AE was diarrhea, reported by 4.5% (6/132) of subjects in the Mg–vitamin B6 combination arm and 7.6% (10/132) in the Mg arm (Table 5).
    
    Who: stressed adults with low magnesemia, magnesium 300 mg a day with or without vitamin B6, 8 weeks
    Effect: treatment-related diarrhea 6/132 (4.5%) with Mg plus B6 and 10/132 (7.6%) with Mg alone; one severe gastroenteritis in the Mg arm
    Certainty: no placebo arm, so background rate of diarrhea unknown
    PLoS One, 2018 · checked 2026-10-06 · we read the fulltext
14. ev-mganx-14 · Position of an expert body · government fact sheet · n = —
    The Tolerable Upper Intake Level for supplemental magnesium is 350 mg for adults, and it ranges from 65 to 350 mg for children and adolescents, depending on age.
    
    Who: adults; children and adolescents 65 to 350 mg depending on age
    Effect: UL for supplemental magnesium 350 mg/day (adults); food magnesium not counted
    Certainty: the 300 mg doses used in anxiety trials sit just under the adult UL
    NIH Office of Dietary Supplements, Magnesium Fact Sheet for Health Professionals · checked 2026-10-06 · we read the section
15. ev-mganx-15 · Position of an expert body · government fact sheet · n = —
    These antibiotics should be taken at least 2 hours before or 4 to 6 hours after a magnesium-containing supplement [57,62].
    
    Who: people taking tetracyclines (doxycycline) or quinolones (ciprofloxacin, levofloxacin)
    Effect: spacing: antibiotic at least 2 h before or 4 to 6 h after magnesium
    Certainty: interaction from pharmacology references cited by ODS
    NIH Office of Dietary Supplements, Magnesium Fact Sheet for Health Professionals · checked 2026-10-06 · we read the section
16. ev-mganx-16 · Position of an expert body · government fact sheet · n = —
    Although the risk of acquiring too much magnesium from food is low among healthy people, high doses of magnesium from dietary supplements or medications can cause diarrhea, nausea, and abdominal cramping.
    
    Who: people taking magnesium supplements or medications
    Effect: diarrhea, nausea, abdominal cramping at high doses; hypotension, irregular heartbeat, cardiac arrest at very high doses
    Certainty: toxicity typically with laxative or antacid doses above 5,000 mg/day or impaired kidney function
    NIH Office of Dietary Supplements, Magnesium Fact Sheet for Health Professionals · checked 2026-10-06 · we read the section