MineralPart of: Magnesium

Magnesium citrate

Also called trimagnesium dicitrate, magnesium dicitrate, Mg citrate

By Kymata Health editorial teamLast reviewed October 8, 2026 · What changed

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Summary

Magnesium citrate is about 16% elemental magnesium by weight and dissolves well. Human comparisons find it better absorbed than magnesium oxide. A 24-week trial found no effect on arterial stiffness or blood pressure (grade C), and a small 30-day study reported lower bone-turnover markers (grade D).

Top graded outcomes:C evidence grade Arterial stiffness and blood pressureD evidence grade Bone-turnover markers

Key facts

What it is
Magnesium salt of citric acid; usually trimagnesium dicitrate, Mg3(C6H5O7)2[2]
Elemental magnesium
16.2% of compound weight (anhydrous): 1,000 mg compound ≈ 162 mg magnesium[2]
Absorption
Higher than oxide by urinary and serum magnesium in human studies[3][4][5]
Studied outcomes
Arterial stiffness and blood pressure: no effect (C); bone-turnover markers (D)[5][6]
RDA / upper limit
Adults 310–420 mg/day magnesium (all sources); UL 350 mg/day from supplements[1]
Main interaction classes
Bisphosphonates, tetracycline and quinolone antibiotics, diuretics, long-term PPIs, high-dose zinc[1][7]
Evidence base
2 graded human outcomes on this page
Last reviewed
October 8, 2026

How it works

EstablishedCitrate keeps magnesium soluble: in laboratory tests magnesium citrate dissolved even in water and stayed largely complexed as soluble magnesium citrate, while magnesium oxide was nearly insoluble. Solubility is the established reason it is absorbed better than oxide.[3][1]

What the human research says

Human trials only, one row per outcome. The form column shows what each trial actually tested. Grades follow our evidence-grading policy.

At a glance: strongest evidence per outcome

Evidence at a glance: strongest human evidence per outcome
OutcomeGradeEffectStrongest evidenceRows
HeartGrade CNo effectRCT · n = 164 · 2022Form tested: magnesium citrate (vs oxide, sulfate)1 rowIncludes this form
Bones & jointsGrade DImprovedOpen-label · n = 20 · 2010Form tested: magnesium citrate1 rowIncludes this form

Every graded row

Outcome
Grade
Form tested
Sort

Showing 2 of 2 outcomes. Human trials only.

OutcomeEffectGradeBest evidencePMID
Arterial stiffness and blood pressureNo effectGrade C

RCT · n = 164 · 2022

Adults with overweight or mild obesity, mean age 63 (four arms: citrate, oxide, sulfate, placebo)

Form: magnesium citrate (vs oxide, sulfate) · Dose: 450 mg/day magnesium · Duration: 24 weeks

Citrate did not change carotid-femoral pulse wave velocity or blood pressure versus placebo. It raised plasma and urinary magnesium, with a larger urinary rise than oxide or sulfate.

35253448 (opens PubMed)Source [5]
Bone-turnover markersImprovedGrade D

Open-label trial · n = 20 · 2010

Postmenopausal women with osteoporosis; untreated, non-placebo control group

Form: magnesium citrate · Dose: 1,830 mg/day magnesium citrate (about 290 mg elemental magnesium per NIH ODS) · Duration: 30 days

Parathyroid hormone and urinary deoxypyridinoline fell and osteocalcin rose, suggesting suppressed bone turnover. Markers only; no bone density outcome.

19488681 (opens PubMed)Source [6]

Forms

FormElemental %Absorption (human data)GI toleranceStudied for
Magnesium glycinate (bisglycinate)14.1%[8]Mg(C2H4NO2)2, MW 172.42; Mg 24.305 g/mol (anhydrous)In 12 people with ileal resection, overall absorption of a 100 mg dose did not differ from oxide (23.5% vs 22.8%), but was higher in the 4 with the poorest oxide absorption (23.5% vs 11.8%).[9]Better tolerated than oxide by all 12 patients in that small crossover trial.[9]Insomnia severity in adults reporting poor sleep (one RCT).
Magnesium citrate16.2%[2]Trimagnesium dicitrate Mg3(C6H5O7)2, MW 451.12 (anhydrous)More soluble and more bioavailable than oxide by urinary magnesium in short studies; in a 60-day RCT (n=46) citrate gave the highest serum magnesium of the forms compared.[3][4]Diarrhea was reported by 18.6% of participants at 600 mg/day in a 12-week migraine trial.[10]Arterial stiffness and blood pressure (null), bone-turnover markers, migraine attack frequency.
Magnesium oxide60.3%[17]MgO, MW 40.305Lowest of the forms tested: about 4% fractional absorption in one comparison; poorly soluble in water.[18][3]One of the forms most often reported to cause diarrhea, per NIH ODS.[1]Arterial stiffness and blood pressure (null in one 24-week trial).
Elemental magnesium in 1,000 mg of each form

Arithmetic from the elemental percentages in the table above. More elemental content per gram says nothing about absorption or tolerance.

Compound weight → elemental magnesium

500 mg magnesium glycinate (bisglycinate) ≈ 71 mg elemental magnesium

Arithmetic only, from the elemental fractions in the table above. US Supplement Facts panels list the elemental amount; front-of-pack claims sometimes give the compound weight. Real products vary with hydration state and buffering.

Studied doses

Doses studied in human trials ranged from about 290 to 600 mg/day of elemental magnesium as citrate, for 30 days to 24 weeks; 600 mg/day (a 12-week migraine trial) exceeds the 350 mg/day upper limit for supplements.[6][1][5][10]

Intake reference: Adult RDA 310–420 mg/day from all sources (by age and sex). Upper limit for supplemental magnesium: 350 mg/day for adults.[1] The upper limit covers supplements and medicines only, not magnesium in food. NIH ODS fact sheet (updated January 6, 2026).

These are amounts used in research, not personal advice. Your clinician or pharmacist can say what fits you.

Interactions

Published interactions only: each row cites a source. No row means none was found in our sources, not that a combination is safe.

Medicines

  • Oral bisphosphonatesNIH fact sheete.g. alendronate (Fosamax)Magnesium-rich supplements or medicines can reduce bisphosphonate absorption; NIH ODS notes separating them by at least 2 hours.[1]
  • Tetracycline and quinolone antibioticsNIH fact sheete.g. doxycycline, ciprofloxacin, levofloxacinMagnesium can form insoluble complexes with these antibiotics; NIH ODS notes taking the antibiotic at least 2 hours before or 4–6 hours after magnesium.[1]
  • Potassium-sparing diureticsNIH fact sheete.g. amiloride, spironolactoneReduce urinary magnesium excretion.[1]

Medicines that can lower levels

  • Loop and thiazide diureticsNIH fact sheete.g. furosemide, bumetanide, hydrochlorothiazideLong-term use can increase urinary magnesium loss and lead to depletion.[1]
  • Proton pump inhibitors (long-term)FDA safety communicatione.g. esomeprazole, lansoprazoleUse typically longer than a year can cause low blood magnesium; in about 25% of cases FDA reviewed, supplements did not correct it and the PPI was stopped.[19][1]

Other supplements

  • High-dose zincPK studye.g. 142 mg/day zinc (as zinc sulfate)Lowered magnesium absorption and magnesium balance in a metabolic-ward study of adult men.[7]

Who should be careful

Kidney problems
The risk of magnesium toxicity rises with impaired kidney function, because the kidneys remove excess magnesium.[1]
High intakes and digestive effects
High doses from supplements or medicines often cause diarrhea, nausea and abdominal cramping. The adult upper limit for supplemental magnesium is 350 mg/day; very large doses from laxatives or antacids (typically over 5,000 mg/day) have caused toxicity.[1]
Pregnancy and breastfeeding
The RDA is 350–400 mg/day in pregnancy and 310–360 mg/day during lactation (all sources), and the 350 mg/day upper limit for supplemental magnesium still applies.[1]
Children
Upper limits for supplemental magnesium are lower: 65 mg/day at ages 1–3 and 110 mg/day at ages 4–8.[1]

Talk to your pharmacist or clinician before starting a supplement, especially if you take prescription medicines.

Articles about Magnesium citrate

Plain-English answers to common questions, built on the evidence above.

Frequently asked questions

Is magnesium citrate better absorbed than magnesium oxide?

Yes in human comparisons. It was more soluble and raised urinary magnesium more than oxide in a load test, gave the highest serum magnesium in a 60-day trial, and raised 24-hour urinary magnesium more than oxide over 24 weeks.[3][4][5]

How much magnesium is in magnesium citrate?

Anhydrous trimagnesium dicitrate is about 16.2% magnesium by weight, so 1,000 mg of the compound carries about 162 mg. Supplement Facts panels list the elemental amount.[2][1]

Does magnesium citrate lower blood pressure?

A 24-week trial in 164 adults with overweight found no effect of 450 mg/day magnesium as citrate, oxide or sulfate on blood pressure or arterial stiffness. Meta-analyses of all forms show a small average drop of about 2 mm Hg.[5][20]

Can magnesium citrate cause diarrhea?

It can at higher doses. In a 12-week trial of 600 mg/day magnesium as trimagnesium dicitrate, 18.6% of participants reported diarrhea. NIH ODS notes high-dose magnesium supplements often cause diarrhea.[10][1]

Sources

  1. [1]Magnesium: Fact Sheet for Health Professionals (updated January 6, 2026). NIH Office of Dietary Supplements, 2026. fact-sheet
  2. [2]Trimagnesium dicitrate (CID 6099959): C12H10Mg3O14, MW 451.12. PubChem, NIH, 2026. database
  3. [3]Magnesium bioavailability from magnesium citrate and magnesium oxide.. J Am Coll Nutr, 1990. PK-study PMID 2407766
  4. [4]Mg citrate found more bioavailable than other Mg preparations in a randomised, double-blind study.. Magnes Res, 2003. RCT PMID 14596323
  5. [5]Effects of Magnesium Citrate, Magnesium Oxide, and Magnesium Sulfate Supplementation on Arterial Stiffness: A Randomized, Double-Blind, Placebo-Controlled Intervention Trial.. J Am Heart Assoc, 2022. RCT PMID 35253448
  6. [6]Short-term oral magnesium supplementation suppresses bone turnover in postmenopausal osteoporotic women.. Biol Trace Elem Res, 2010. open-label PMID 19488681
  7. [7]Inhibitory effects of zinc on magnesium balance and magnesium absorption in man.. J Am Coll Nutr, 1994. PK-study PMID 7836627
  8. [8]Magnesium glycinate (CID 84645): C4H8MgN2O4, MW 172.42. PubChem, NIH, 2026. database
  9. [9]Bioavailability of magnesium diglycinate vs magnesium oxide in patients with ileal resection.. JPEN J Parenter Enteral Nutr, 1994. crossover-RCT PMID 7815675
  10. [10]Prophylaxis of migraine with oral magnesium: results from a prospective, multi-center, placebo-controlled and double-blind randomized study.. Cephalalgia, 1996. RCT PMID 8792038
  11. [11]Magnesium L-threonate (CID 45489777): C8H14MgO10, MW 294.50. PubChem, NIH, 2026. database
  12. [12]Enhancement of learning and memory by elevating brain magnesium.. Neuron, 2010. animal-study PMID 20152124
  13. [13]Magnesium-L-threonate improves sleep quality and daytime functioning in adults with self-reported sleep problems: A randomized controlled trial.. Sleep Med X, 2024. RCT PMID 39252819
  14. [14]The effects of magnesium L-threonate (Magtein®) on cognitive performance and sleep quality in adults: a randomised, double-blind, placebo-controlled trial.. Front Nutr, 2025. RCT PMID 41601871
  15. [15]Magnesium malate (CID 164748): C4H4MgO5, MW 156.38. PubChem, NIH, 2026. database
  16. [16]Magnesium taurate (CID 13343447): C4H12MgN2O6S2, MW 272.6. PubChem, NIH, 2026. database
  17. [17]Magnesium oxide (CID 14792): MgO, MW 40.305. PubChem, NIH, 2026. database
  18. [18]Bioavailability of US commercial magnesium preparations.. Magnes Res, 2001. PK-study PMID 11794633
  19. [19]FDA Drug Safety Communication: Low magnesium levels can be associated with long-term use of proton pump inhibitor drugs (PPIs). U.S. Food and Drug Administration, 2011. safety-communication
  20. [20]Effects of Magnesium Supplementation on Blood Pressure: A Meta-Analysis of Randomized Double-Blind Placebo-Controlled Trials.. Hypertension, 2016. meta-analysis PMID 27402922

What changed

  1. October 8, 2026 · all · new pageFirst published.Writer: Kymata Health editorial team · No credentialed reviewer yet

How we write, grade and correct these pages: editorial and evidence policy.

Supplement & Nutrient Encyclopedia. Educational information only; it is not medical advice and does not replace a clinician. Dietary supplements are not intended to diagnose, treat, cure or prevent any disease. Statements about supplements have not been evaluated by the FDA.