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Macromineral·Vitamins & Minerals
Historically used for magnesium deficiency
Max Dose
1000 mg/day
Bioavailability
POOR (4%)
Diarrhea
SEVERE RISK
Replacement
USELESS
Overview
Inorganic magnesium salt. Notoriously cheap, but has a miserable 4% oral bioavailability. Mostly stays in the gut where it acts as a potent osmotic laxative.
Maximum Dose
Max 1000 mg/day.
Clinical Focus
Do not use Magnesium Oxide to replenish low blood magnesium levels. It does not absorb. Use Magnesium Aspartate or Citrate instead.
Bottom Line
Magnesium oxide is a common oral magnesium supplement and osmotic laxative, but has the poorest oral bioavailability of all magnesium salts and frequently causes diarrhoea.
Brand Names
Various OTC
Oral Routes
Tablets.
Prescribing & PBS
Over The Counter (OTC).
Primary
Historically used for magnesium deficiency.
Clinical Place
Largely obsolete for electrolyte replacement. Only useful if you want to cause diarrhea.