Mg²⁺ salt of citric acid. Walker 2003 established citrate as more bioavailable than oxide, sulfate, or chelate-amino-acid in a double-blind crossover — urinary Mg excretion was highest on citrate. Citrate is absorbed largely intact via transcellular paracellular pathways; residual luminal citrate acts as an osmotic laxative, making it the most GI-active of the 'good' organic Mg forms. Common OTC form in the US.
Half-Life (t½)
PO: 12h
Dosing Guidelines
PO: Typical 367 mg (Range: 300–500 mg)
Target Organ Systems
renal
Interactions
Magnesium (synergistic): Same elemental mineral — citrate is the common OTC baseline.
Magnesium glycinate (synergistic): Use glycinate instead if citrate's laxative effect is dose-limiting.