Bioavailability of US commercial magnesium preparations.
Level 3 - non-randomized controlled study
Comparative interventional trial in healthy volunteers without reported randomization details in the abstract
What was done
Healthy normal volunteers were administered approximately 21 mEq/day of four commercially available magnesium preparations: magnesium oxide, magnesium chloride, magnesium lactate, and magnesium aspartate. Bioavailability was assessed by measuring the increment in urinary magnesium excretion to evaluate whether organic salts are absorbed more readily than inorganic salts.
What was found
Magnesium oxide exhibited relatively poor bioavailability with a fractional absorption of 4 per cent. Magnesium chloride, magnesium lactate, and magnesium aspartate showed significantly higher and mutually equivalent bioavailability. Specific numerical absorption rates, variance measures, and p-values for chloride, lactate, and aspartate were not reported in the abstract.
Why it matters
The study indicates that oral magnesium oxide is poorly absorbed compared to other standard formulations, and demonstrates that inorganic magnesium salts can achieve oral bioavailability equivalent to organic salts.
Limits
The abstract does not state the sample size, participant demographics, study duration, or whether allocation was randomized or crossed over. Bioavailability was measured exclusively via urinary excretion without direct assessment of serum levels or intracellular magnesium status.
Cited by
- supports Magnesium oxide has an absorption rate of only 4 percent in the human body.