What form of magnesium is gentle on the stomach?

Magnesium Forms Gentle on the Stomach

Magnesium glycinate and magnesium bisglycinate are the gentlest forms on the stomach, causing minimal gastrointestinal side effects compared to other magnesium formulations. 1

Why Organic Magnesium Salts Are Better Tolerated

Organic magnesium salts (glycinate, citrate, aspartate, lactate) have superior bioavailability and cause fewer GI side effects than inorganic forms like magnesium oxide or hydroxide. 1 The key difference lies in their absorption mechanism:

• Magnesium glycinate is chelated to the amino acid glycine, which protects it from causing osmotic diarrhea that commonly occurs with poorly absorbed forms 1
• Organic forms are absorbed more efficiently in the small intestine, leaving less unabsorbed magnesium to draw water into the colon 1
• Magnesium oxide, while containing more elemental magnesium per dose, has poor bioavailability (only 4% absorbed) and causes significant osmotic effects leading to loose stools 1, 2

Specific Formulation Recommendations

For patients prioritizing stomach tolerance, start with magnesium glycinate or bisglycinate at 320 mg daily for women or 420 mg daily for men (the RDA). 1 These forms demonstrated:

• Minimal increase in intestinal motility in clinical studies 3
• Reduced sensations of gastric heaviness compared to other forms 4
• Better tolerance with sustained supplementation 4

Liquid or dissolvable magnesium products are generally better tolerated than pills across all formulations. 1 This is particularly important for patients with sensitive stomachs or those who experience nausea with tablets.

Alternative Well-Tolerated Options

If glycinate is unavailable or cost-prohibitive, consider these alternatives in order of GI tolerability:

1. Magnesium citrate - Better absorbed than oxide, moderate GI effects 1, 5
2. Magnesium malate (timed-release formulation) - 91% of participants tolerated it well with minimal GI symptoms over 90 days 6
3. Sucrosomial magnesium - Microencapsulated technology that reduces adverse GI effects while maintaining bioavailability 5

When Magnesium Oxide May Be Necessary Despite GI Effects

The only scenario where magnesium oxide is preferred is for chronic constipation, where its osmotic diarrhea effect is actually therapeutic. 1, 2 For constipation:

• Start with 400-500 mg magnesium oxide daily and titrate based on response 1
• The AGA recommends this as first-line laxative therapy 7
• Take at night when intestinal transit is slowest to minimize daytime diarrhea 1, 2

Critical Safety Considerations

Avoid all magnesium supplementation if creatinine clearance is <20 mL/min due to life-threatening hypermagnesemia risk. 1, 8 Check renal function before initiating any magnesium supplement. 1

Common pitfall: Assuming all magnesium forms cause equal GI distress. This leads to patients abandoning supplementation entirely when switching to glycinate or citrate would solve the problem. 1

Practical Dosing Algorithm

1. Start with magnesium glycinate 200-400 mg daily (taken with food to further minimize any GI effects) 1
2. Increase gradually to target dose (320 mg for women, 420 mg for men) over 1-2 weeks based on tolerance 1
3. If diarrhea occurs even with glycinate, split the dose to twice daily or switch to a timed-release formulation 6
4. Monitor magnesium levels at 2-3 weeks, then every 3 months once stable 1

What to Avoid

Never use magnesium hydroxide or magnesium sulfate (Epsom salts) orally for supplementation purposes - these are potent laxatives with very poor absorption and will cause significant diarrhea. 7 They are reserved for acute constipation treatment, not chronic supplementation.