Magnesium Confusion. What form? At what dose?

Choosing the right form of Magnesium and at the right dose is important to the effectiveness of clinical prescriptions. Magnesium is the mineral practitioners most often prescribe. But are we getting it right?

While methodological differences occur with many Magnesium bioavailability studies, Magnesium citrate appears to be one of the most bioavailable. Solubility of any Magnesium salt is important to its bioavailability. Magnesium citrate is reported to be highly soluble with one study finding it nine times more soluble than the oxide form(1). Although there have not been any studies comparing the bioavailability of Magnesium diglycinate directly with Magnesium citrate, the two forms appear to have similar solubility with one publication suggesting Magnesium diglycinate was 8.8 times more absorbable than Magnesium oxide(2).

Interestingly, unlike the diglycinate form, the solubility of Magnesium citrate appears less dependent on pH/acid levels (1). This may provide clinicians with a distinct advantage when prescribing the citrate form to patients who present with varying degrees of hypochlorhydria.

Another study compared the absorption of Magnesium citrate to Magnesium oxide and Magnesium amino acid chelate. Each study group received 300mg of elemental Magnesium. The researchers found Magnesium citrate more bioavailable than Magnesium amino acid chelate and Magnesium oxide. Only the Magnesium citrate group experienced a greater increase in plasma Magnesium levels after short-term (24 hours) and long-term (60 days) administration(3).

Administering the correct dosage is crucial to efficacy, and in the case of Magnesium citrate, 300mg per dose reflects that used in scientific literature for therapeutic effects in a number of conditions(4).

References available upon request