What is the safe dosage of magnesium glycine (Mg(Gly)2)?

Safe Dosage of Magnesium Glycinate

The safe dosage of magnesium glycinate is 320 mg/day for women and 420 mg/day for men, with a tolerable upper intake level of 350 mg/day from supplements (exclusive of food and water intake) to avoid adverse effects. 1

Recommended Dosages Based on Guidelines

Magnesium glycinate is an organic magnesium salt that combines magnesium with the amino acid glycine. When considering safe dosages, it's important to understand both the recommended daily allowances and upper limits:

• Recommended Dietary Allowance (RDA):

  • Adult women: 320 mg/day of elemental magnesium
  • Adult men: 420 mg/day of elemental magnesium 1

• Tolerable Upper Intake Level (UL):

  • 350 mg/day from supplements (exclusive of food and water intake) 1

Magnesium Glycinate vs. Other Forms

Magnesium glycinate is considered an organic magnesium salt with several advantages over inorganic forms:

• Organic magnesium salts (glycinate, citrate, lactate, aspartate) have higher bioavailability than inorganic forms like magnesium oxide or hydroxide 1, 2
• The amino acid glycine itself has anti-inflammatory, cytoprotective, and immunomodulatory properties that may provide additional benefits 3
• Magnesium glycinate is generally better tolerated with fewer gastrointestinal side effects than other forms 2

Dosing Considerations and Safety

When determining appropriate dosing of magnesium glycinate, consider these factors:

1. Elemental magnesium content: Magnesium glycinate contains approximately 14% elemental magnesium, so dosing should be calculated based on the elemental content

2. Timing and frequency:

   • Dividing doses throughout the day is recommended for better absorption 1
   • Taking magnesium at night may be beneficial as intestinal transit is slower 1

3. Special populations:

   • Renal impairment: Avoid magnesium supplements in those with creatinine clearance <20 mg/dL due to risk of hypermagnesemia 1
   • Pregnancy/lactation: Requirements remain the same as for non-pregnant women

4. Monitoring: For those taking regular supplementation, monitoring serum magnesium levels may be appropriate, with a target level >0.6 mmol/L considered reasonable 1

Potential Adverse Effects

Exceeding the tolerable upper intake level may lead to:

• Diarrhea and gastrointestinal disturbances 1
• Decreased intestinal motility at high doses 4
• Potential drug interactions with certain medications (antibiotics, diuretics)

Clinical Application Algorithm

1. Assess need for supplementation:

   • Dietary intake <250 mg/day
   • Urinary excretion <80 mg/day
   • Serum magnesium <0.85 mmol/L 5

2. Start with appropriate dose:

   • Begin with 100-200 mg elemental magnesium daily
   • For therapeutic purposes in deficiency: 4 mmol (160 mg) magnesium up to 12-24 mmol daily 1

3. Adjust based on response and tolerance:

   • Increase gradually if needed and tolerated
   • Divide into multiple doses if GI side effects occur
   • Never exceed 350 mg/day from supplements 1

4. Monitor for effectiveness and side effects:

   • Improvement in symptoms of deficiency
   • Absence of diarrhea or other GI disturbances

Magnesium glycinate represents one of the better-absorbed forms of magnesium supplementation with fewer gastrointestinal side effects, making it suitable for long-term use when needed, but dosing should always respect the established upper limits to prevent adverse effects.