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Magnesium Side Effects & Safety

Evidence:Strong
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This content is for informational purposes only and does not constitute medical advice. Statements about dietary supplements have not been evaluated by the FDA and are not intended to diagnose, treat, cure, or prevent any disease. Individual results may vary — consult your healthcare provider before starting any supplement. Full disclaimer

Safety Profile

Overall safety rating: Generally Safe

Potential Side Effects

  • Digestive upset (most common with magnesium oxide and citrate)
  • Diarrhea at high doses (especially citrate)
  • Nausea when taken on empty stomach
  • Very rare: low blood pressure at extremely high doses

Drug & Supplement Interactions

  • May reduce absorption of bisphosphonates, antibiotics (tetracyclines, quinolones)
  • May interact with blood pressure medications
  • Zinc supplements may reduce magnesium absorption at high doses
  • Separate from calcium supplements by 2 hours for optimal absorption

Maximum Dose

Do not exceed: 350mg/day from supplements (NIH Upper Tolerable Intake Level)

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References

  1. ReviewBoyle NB, Lawton C, Dye L (2017). The Effects of Magnesium Supplementation on Subjective Anxiety and Stress—A Systematic Review. Nutrients. DOI PubMed
  2. ReviewArab A, Rafie N, Amani R, Shirani F (2023). The Role of Magnesium in Sleep Health: a Systematic Review of Available Literature. Biological Trace Element Research. DOI PubMed
  3. Meta-analysisArgeros Z, Xu X, Bhandari B, Harris K, et al. (2025). Magnesium Supplementation and Blood Pressure: A Systematic Review and Meta-Analysis of Randomized Controlled Trials.. Hypertension (Dallas, Tex. : 1979). DOI PubMed
  4. Meta-analysisChen F, Wang J, Cheng Y, Li R, et al. (2024). Magnesium and Cognitive Health in Adults: A Systematic Review and Meta-Analysis.. Advances in nutrition (Bethesda, Md.). DOI PubMed
  5. Meta-analysisCurran J, Ross-White A, Sibley S (2023). Magnesium prophylaxis of new-onset atrial fibrillation: A systematic review and meta-analysis.. PloS one. DOI PubMed
  6. Meta-analysisGroenendijk I, van Delft M, Versloot P, van Loon LJC, et al. (2022). Impact of magnesium on bone health in older adults: A systematic review and meta-analysis.. Bone. DOI PubMed