Magnesium Citrate

MineralStrong dose evidence

Also known as: trimagnesium citrate, magnesium citrate anhydrous, Mg citrate

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Magnesium bound to citric acid, one of the best-selling magnesium forms because it is inexpensive, dissolves readily, and has shown good bioavailability in comparison studies. It carries about 16% elemental magnesium as the anhydrous tribasic salt. Its well-known drawback is an osmotic laxative effect at higher doses, which some regularity products use deliberately but which limits how much fits comfortably in a single serving.

Research summary

Supplies magnesium for ATP-dependent enzymes, neuromuscular signaling, and bone; unabsorbed citrate salt draws water into the bowel, which explains the loosening effect.

Dosage

Daily amounts, elemental (16% of the compound is the element).

Lowest studiedTypical rangeHighest studiedUpper limit
100 mg150–350 mg350 mg350 mg

NIH ODS — UL of 350 mg applies to supplemental magnesium only, not magnesium from food

Doses are elemental magnesium. Loose stools become common above roughly 300–400 mg elemental in one sitting, so larger amounts are usually split or moved to a powder taken with water. The 350 mg UL applies to supplemental magnesium; trials of magnesium citrate have gone higher but the app caps at the UL. Anhydrous tribasic citrate is ≈ 16% Mg; the nonahydrate is closer to 11%, so verify the grade on the certificate of analysis.

Source material: synthetic (magnesium carbonate or oxide reacted with citric acid)

As supplied: Anhydrous tribasic ≈ 16% Mg; hydrated grades ≈ 11% Mg

Forms of Magnesium

FormTypical doseElement %FormatsPrice
Magnesium Citrate150–350 mg16%Capsule, Powder, Tablet, Gummy, Liquidlow
Magnesium Glycinate200–350 mg14%Capsule, Powder, Tabletlow
Magnesium Oxide200–350 mg60%Capsule, Powder, Tablet, Gummylow
Magnesium L-Threonate100–144 mg7%Capsule, Powder, Tablethigh
Magnesium Malate100–350 mg16%Capsule, Powder, Tabletlow
Magnesium Chloride100–300 mg12%Capsule, Powder, Tablet, Liquidlow
Magnesium Taurate100–300 mg9%Capsule, Powder, Tabletmid

Format suitability

  • Capsule
  • Powder
  • Tablet
  • Softgel
  • Gummy
  • Liquid

Bulky: 200 mg elemental ≈ 1,250 mg of compound, about two and a half size-00 capsules. Very soluble with a mild tart taste, so it is the go-to form for drink powders and effervescents. Hygroscopic; protect from moisture.

Formulation notes

Separate from some antibiotics and bisphosphonates by two hours. Stacks well with vitamin B6 and with potassium citrate in electrolyte blends.

  • Has an upper limit

Sources

  1. Magnesium — Health Professional Fact SheetNIH ODS
  2. Mg citrate found more bioavailable than other Mg preparations in a randomised, double-blind study (Walker 2003)PubMed
  3. Oral magnesium supplementation for insomnia in older adults: a Systematic Review & Meta-Analysis (Mah 2021)PubMed

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