ingestible · for kidney stone prevention
Magnesium Citrate Supplement
Reviewed by the Nimbera editorial team · Last updated May 2026
How to use
Take 200-400 mg of magnesium citrate daily with meals, split into two or three doses. The citrate form is preferred over magnesium oxide because it is better absorbed and also contributes urinary citrate. Start at a lower dose (200 mg/day) and increase gradually over 1-2 weeks to minimize gastrointestinal side effects. Take consistently rather than intermittently.
How it works
Magnesium binds oxalate in the gut, reducing intestinal absorption and urinary oxalate excretion; the citrate component simultaneously raises urinary citrate, a natural inhibitor of calcium crystal formation.
Where to buy
Pharmacies (Walgreens, CVS, Rite Aid), health food stores (Whole Foods, Sprouts), and online retailers. Look for magnesium citrate capsules or powder, not the liquid laxative form which contains much higher doses.
Typical cost: $10-20/month
Safety notes
High doses cause osmotic diarrhea - the over-the-counter liquid laxative form (typically 1.75 g/dose) is far too strong and should not be used for this purpose. Magnesium supplements interact with certain antibiotics (tetracyclines, fluoroquinolones) and bisphosphonates - separate doses by at least 2 hours. Contraindicated in severe kidney disease (eGFR below 30) as magnesium can accumulate to toxic levels. Consult a doctor before use if you have any kidney impairment.
Drug & supplement interactions
- Always tell your doctor or pharmacist about any supplements you take.
- Interactions can occur with prescription medications, blood thinners, and immunosuppressants.
- Herbal remedies can affect how the body absorbs or metabolises drugs.
- Check drugs.com interactions checker before starting.
Clinical source
Magnesium Research 2024This information is compiled from primary clinical literature and is for informational purposes only. It is not a substitute for professional medical advice. Read our full disclaimer.