How to prevent gastrointestinal (GI) upset with magnesium?

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Last updated: April 30, 2025View editorial policy

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From the Guidelines

To prevent gastrointestinal upset with magnesium supplements, it is recommended to start with a low dose of a gentle form, such as magnesium glycinate or magnesium citrate, and gradually increase as needed, while also taking the supplement with food and staying well-hydrated, as suggested by the most recent guidelines 1. When considering magnesium supplementation, it's essential to prioritize forms that are less likely to cause gastrointestinal upset. Magnesium glycinate, magnesium citrate, and magnesium malate are generally better tolerated than magnesium oxide.

  • Take magnesium with food to reduce irritation, as taking it on an empty stomach can exacerbate gastrointestinal issues.
  • Begin with a low dose, around 100-200mg, and gradually increase to the target dose over several days or weeks, allowing the body to adjust.
  • Divide the daily dose into smaller amounts taken 2-3 times throughout the day instead of one large dose to minimize digestive distress.
  • Stay well-hydrated when taking magnesium supplements, as adequate hydration can help reduce the risk of gastrointestinal side effects. The American Gastroenterological Association-American College of Gastroenterology clinical practice guideline suggests the use of magnesium oxide for the management of chronic idiopathic constipation, but it also notes the importance of starting with a lower dose and increasing as necessary, while avoiding use in patients with renal insufficiency due to the risk of hypermagnesemia 1. Given the potential for gastrointestinal upset with magnesium supplements, it's crucial to approach supplementation with caution and consider the most gentle forms and dosing strategies to minimize adverse effects, as supported by recent studies 1.

From the FDA Drug Label

Ask a doctor before use if you have ... stomach pain, nausea, or vomiting The FDA drug label does not answer the question.

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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