What is the recommended magnesium supplementation dose for an adult?

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Last updated: April 11, 2025View editorial policy

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From the FDA Drug Label

PRINCIPAL DISPLAY PANEL - 30 mL Cup Tray Label NDC 0121-0431-30 Milk of Magnesia USP ANTACID, SALINE LAXATIVE Each 30 mL contains: Magnesium Hydroxide 2400 mg SHAKE WELL USUAL DOSAGE:See attached Drug Facts Package

The usual dosage is not explicitly stated in the provided text, but it mentions to see the attached Drug Facts Package for the dosage information.

  • The amount of Magnesium Hydroxide in each 30 mL is 2400 mg.
  • However, the exact amount of magnesium to supplement is not directly provided.
  • Since the FDA label does not directly answer the question, no conclusion can be drawn about the supplement amount for an adult 1.

From the Research

For most adults, a daily magnesium supplement of 300-400 mg is appropriate if supplementation is needed, as it is unlikely to cause harm and may provide benefits for muscle function and overall health 2. When considering magnesium supplementation, it's essential to prioritize the recommended dietary allowance (RDA) for magnesium, which is 400-420 mg daily for men and 310-320 mg daily for women, with slightly higher amounts recommended during pregnancy. Some key points to consider when supplementing with magnesium include:

  • Common supplement forms include magnesium citrate, glycinate, and oxide, with citrate and glycinate generally being better absorbed than oxide 3.
  • Taking supplements with food can improve absorption and reduce potential digestive side effects.
  • Splitting the dose throughout the day if taking more than 200 mg at once can help minimize side effects.
  • Being aware that excessive magnesium supplementation can cause diarrhea, nausea, or abdominal cramping.
  • Consulting a healthcare provider before supplementing if you have kidney disease, as impaired kidney function can lead to magnesium accumulation. Magnesium is essential for over 300 biochemical reactions in the body, including muscle and nerve function, blood glucose control, and bone health, making supplementation beneficial for those with inadequate intake or increased needs 4. It's also important to note that some studies have shown that magnesium supplementation can reduce muscle soreness and improve performance, although more research is needed to confirm these findings 4. Overall, while the evidence for magnesium supplementation is not yet conclusive, a daily supplement of 300-400 mg is a reasonable and safe recommendation for most adults.

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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