Mg citrate found more bioavailable than other Mg preparations in a randomised, double-blind study.
Level 2 - randomized trial
Individual randomized controlled trial
What was done
A randomized, double-blind, placebo-controlled, parallel trial evaluated the relative bioavailability of three magnesium preparations (amino-acid chelate, citrate, and oxide) at a daily dose of 300 mg elemental magnesium versus placebo in 46 healthy individuals over 60 days. Urine, blood, and saliva samples were collected at baseline, at 24 hours after the first dose (acute supplementation), and after 60 days of daily intake (chronic supplementation).
What was found
Organic forms (citrate and amino-acid chelate) showed significantly greater absorption than magnesium oxide at 60 days as measured by 24-hour urinary excretion (P = 0.033). Magnesium citrate produced the greatest mean serum magnesium concentration compared with other treatments following acute (P = 0.026) and chronic (P = 0.006) supplementation. Chronic magnesium citrate supplementation also led to the greatest mean salivary magnesium concentration (P = 0.027). Mean erythrocyte magnesium concentration showed no significant differences among groups, and magnesium oxide showed no differences compared to placebo. Absolute numerical values for concentrations and excretion were not reported in the abstract.
Why it matters
This study provides comparative bioavailability data showing that organic magnesium formulations, particularly magnesium citrate, are better absorbed than inorganic magnesium oxide in humans.
Limits
The sample size is small (46 participants across four parallel arms). Absolute baseline and follow-up values, variances, and demographic details are not reported in the abstract, and clinical outcomes beyond biochemical markers were not evaluated.
Cited by
- supports Magnesium oxide has an absorption rate of only 4 percent in the human body.