Magnesium Citrate

Magnesium citrate refers to the magnesium salt or salts of citric acid, a family that includes several stoichiometries such as the 1:1 form and trimagnesium dicitrate. It is a white to slightly off-white material that dissolves readily in water, and it carries the food-additive designation E345 ^[5]. The elemental magnesium it delivers is relatively modest by weight, so products are formulated to supply a target quantity of the mineral rather than of the salt itself. Commercially it appears as powders that are reconstituted into oral solutions, as well as in capsules and tablets ^[5].

Interest in magnesium citrate as a supplement stems in part from comparisons of how efficiently different magnesium salts are absorbed. In a randomized, double-blind trial in healthy adults, citrate produced higher serum and salivary magnesium than magnesium oxide after both single and repeated intake, and the organic salts as a group were absorbed more completely than the oxide ^[1]. Reviews of magnesium pharmacokinetics have similarly observed that the anion paired with magnesium influences how much elemental mineral reaches the circulation, with more soluble organic salts tending to be favored ^[2]. Animal studies comparing several compounds report that citrate can raise tissue magnesium, although some rank other organic forms higher on particular measures ^[3][4].

The compound's other major role is as an osmotic laxative. Because incompletely absorbed magnesium salts retain water within the intestinal lumen, an oral dose draws fluid into the bowel and promotes evacuation, an effect shared by other magnesium cathartics ^[2][5]. This property underlies its use in relieving short-term constipation and in regimens that empty the colon before endoscopic or surgical procedures. The same osmotic action means that larger intakes can loosen stools and cause cramping or diarrhea, which is a common reason people notice gastrointestinal effects from magnesium supplements ^[5].

As a dietary ingredient, magnesium citrate is one of many permitted sources used to help meet the recommended intake of magnesium, a mineral involved in hundreds of enzymatic reactions in the body ^[5]. Health authorities set a tolerable upper intake level for magnesium obtained from supplements and medicines, kept separate from magnesium naturally present in food, because it is supplemental magnesium that tends to produce the laxative and other dose-related effects ^[5]. Magnesium citrate is widely available over the counter in many countries as a generic product and under various brand names, and it is generally regarded as safe when used as directed, with added caution advised for people who have impaired kidney function ^[2][5].

Very safe in healthy people; the main side effect is loose stools or diarrhea, which limits how much you can take. People with significant kidney disease should be cautious since they clear magnesium poorly. It can bind certain medications like some antibiotics, so separate dosing.