A reference work, not a recommendation to use: this profile describes mechanism and evidence and does not replace medical advice. The claims come from marketing and forums and are tested here, not endorsed.

Claims checked

  • Better sleep

    No benefit

    Sleep · healthy (older adults with poor sleep) · Human, randomised

    In the RCT with citrate (placebo: sodium citrate), the sleep index improved equally under verum and placebo [9]. A meta-analysis of three small RCTs found a shorter time to fall asleep with low to very low quality evidence; it pools oxide and citrate and therefore does not count toward the rating [10].

  • Fewer muscle cramps

    No benefit

    Muscle & performance · healthy (adults with regular nocturnal calf cramps) · Human, randomised small studiesEvery study behind this level and result had fewer than 100 participants. Small studies report larger effects on average than large ones, so the result is less certain.

    Two randomized, double-blind, placebo-controlled crossover studies with citrate found no significant difference in the number of cramps (explicitly the primary endpoint in [19]): in 46 people only a trend (p = 0.07) with a strong period effect, severity and duration unchanged [16]; in 45 people no difference in any endpoint (11.8 vs. 11.1 cramps, p = 0.59) [19]. Only the subjective assessment in one of the two studies was more favorable (78 vs. 54%, p = 0.03) [16]; a secondary endpoint does not support a benefit. The Cochrane review, which saw no relevant benefit in older people, pools different forms of magnesium and does not count toward the rating [12].

  • Stress ↓, less anxiety

    No benefit

    Mood & stress · healthy (students before an exam) · Human, randomised

    Only study found with citrate: double-blind, placebo-controlled study with 122 evaluated students; state anxiety on the evening before the first final exam did not differ from placebo (p = 0.69) [20], as also reported in the systematic review [14]. What has thus been tested is only acute, situational exam anxiety after five days of intake, not chronic anxiety or stress; the review emphasizes that the sample and anxiety context differ markedly from the studies in chronically anxious people [14]. The other studies in the review (positive effects in about half, poor study quality) used other forms of magnesium and do not count toward the rating [14].

small studies: Every study behind this level and result had fewer than 100 participants. Small studies report larger effects on average than large ones, so the result is less certain.

Mechanism of action

Evidence map: Magnesium citrate

Each line stands for a published finding; line style and color show where it comes from. The filter hides weaker evidence levels. Sources: see references.

Magnesium is involved in more than 600 enzymatic reactions; the gut, kidney and bone regulate its levels [1]. In nerve cells, Mg2+ blocks the NMDA receptor channel in a voltage-dependent manner [2]. These effects apply to magnesium in general; what differs between the salts is mainly how much magnesium is absorbed.

In the experiment, magnesium citrate was already 55% dissolved in water, whereas oxide hardly dissolved and even under simulated maximal stomach acid only 43%; after a single dose, urinary magnesium excretion in healthy people rose markedly more after citrate than after oxide [3]. In a randomized study of 46 healthy people, citrate led to the highest serum level acutely and after 60 days, compared with an amino acid chelate and oxide [4]. Two studies with previously saturated magnesium stores confirmed higher urinary excretion than after oxide: in 20 men on average 0.565 mmol more in 24 hours, funded by the citrate supplier Verla-Pharm [5], in 14 men a significant rise only after citrate [6]. A systematic review found organic salts overall more available than inorganic ones, but considers all products suitable for maintaining normal levels in healthy people without deficiency [7]. An advantage over other organic salts has not been demonstrated; in a rat study, citrate and oxide were even among the least available of five compounds [8].

In 100 older adults with poor sleep, the sleep index improved equally under citrate and placebo [9]; a meta-analysis of three small RCTs with oxide and citrate found a shorter time to fall asleep, with low to very low quality evidence [10]. In an RCT with 81 people with migraine, trimagnesium dicitrate reduced attack frequency more than placebo (41.6 vs. 15.8%); diarrhea occurred in 18.6% [11]. A Cochrane review found no relevant benefit of magnesium in older people with nocturnal calf cramps [12]. As a laxative, magnesium citrate is used together with sodium picosulfate in bowel preparation; in that setting, the serum level on the day of the examination was 10% above the normal range and normalized within 24 to 48 hours [13].

Studies specifically with citrate on the remaining advertising promises: a systematic review on anxiety and stress pools different forms of magnesium; the only citrate study in it (RCT, 122 students, five days before an exam) found no difference from placebo [14]. In a randomized, double-blind crossover study of 46 volunteers with regular calf cramps, citrate showed only a trend toward fewer cramps (p = 0.07), severity and duration did not differ, with a marked period effect; more participants considered the treatment helpful (78 vs. 54%), and diarrhea occurred as a side effect [16]. A second randomized, double-blind crossover study of 45 people with nocturnal calf cramps found no difference in any endpoint (on average 11.8 cramps under citrate vs. 11.1 under placebo, p = 0.59); all participants improved over the course of the study regardless of the order of treatments [19]. According to the original paper of the anxiety study, 147 students were enrolled and 122 evaluated; they received citrate or a gelatin placebo double-blind over the five days before their first final exam, and state anxiety on the evening before the exam did not differ (p = 0.69) [20].

Synaptik serves solely to explain biochemistry and pharmacology and is not medical advice or a recommendation to take anything.

Mechanism of action only. Schematic section through an excitatory synapse, not to scale: of the NMDA receptor (a tetramer of two GluN1 and two GluN2B subunits) the two rear subunits are drawn and the front two are cut away to expose the pore. The sequence repeats in three beats: glutamate with depolarisation, glutamate alone, depolarisation alone. Particle numbers, timings, openings and the Ca²⁺ influx are outputs of this figure's model, not measurements, and are not shown as numbers. The numbers in the bottom-right readout come from laboratory and animal experiments and are not comparable with each other.
Drug
View

Glutamate  Glycine / D-serine  Mg²⁺  Ca²⁺  Na⁺  K⁺  red = drug, shown in the scene as a miniature skeletal formula · shapes as in the figure

Magnesium citrate supplies Mg²⁺. This ion already plugs the pore at baseline and leaves on depolarisation [3], so the figure only highlights it and leaves the model unchanged. Whether more magnesium from food or salts strengthens the block in the brain has not been shown. How much magnesium is absorbed from each salt is covered in the form profiles.

Tap or focus a labelled part for a one-line explanation.

Also acting here, not drawn

  • CX-717: ampakine; NMDA effect only indirect, no action on the receptor itself
  • Huperzine A: NMDA inhibition only in a review by the developers’ group, without a binding site
  • L-theanine: only very weak binding to glutamate receptors
  • Phenylpiracetam: no displacement of ligands at NMDA receptors
  • Piracetam: only changed receptor numbers (mice)
  • Selank: only changed numbers of binding sites (mice)

What the figure shows, and how sure we are

Mechanism-of-action explainer only. Not medical advice, and no statement about benefit, risk, amount or use. Ketamine, esketamine, memantine and atomoxetine are medicines; most of the other substances have been studied at the NMDA receptor only in the lab or in animals.

What was simplified. One receptor stands for many; sizes, cleft width, membrane thickness, ion numbers and all timings are illustrative. The rear two subunits of a GluN1-GluN2B receptor are drawn; NMDA receptors with GluN2A and other subunits, and the AMPA receptors that help produce the depolarisation, are left out. The positions of Mg²⁺ in the filter and of ketamine in the vestibule follow [2] and [8]; for atomoxetine and crocetin the position in the pore has not been determined, and for agmatine the binding site at all. The numbers in [3], [4], [9], [11] to [18], [20] to [22], [24] and [26] to [32] come from the Synaptik drug profiles, where they were checked against the abstracts; [1], [5] to [8], [19], [23] and [25] were checked against their PubMed abstracts (25 Oct 2026), and the statements taken from the review [2] (M1, M3, M4 and the pore loop M2, M3 as the gate, the Mg²⁺ site at the tip of M2, Na⁺, K⁺ and Ca²⁺ as charge carriers, kinases and scaffold proteins at the C-terminal domain of GluN2B) against the relevant sections of the full text.

If medicines, alcohol or other substances are causing problems, a GP or a local addiction counselling service can help.

Targets

TargetTypeActionKey dataEvidence
NMDA receptor, channel poreIon channelInhibitorvoltage-dependent block by Mg2+ (mouse neurons) Laboratory[2]

Effect profile

Which signaling systems the compound affects according to current data. ↑ enhanced, ↓ dampened, ≈ modulated, ○ no effect; dots = evidence level.

  • Dopamineno data
  • Noradrenalineno data
  • Serotoninno data
  • Acetylcholineno data
  • Glutamate · AMPAno data
  • Glutamate · NMDA↓ · Mg2+ blocks the NMDA channel in a voltage-dependent manner (laboratory); not form-specific[2]
  • GABAno data
  • Histamineno data
  • Orexinno data
  • Adenosineno data
  • Opioidsno data
  • Melatoninno data
  • Neurotrophinsno data
  • Blood flowno data
  • Nitric oxideno data
  • Energy metabolismno data
  • Insulin · glucoseno data
  • Inflammation · oxidative↓ · CRP lowered only in people with an elevated baseline value (older adults with poor sleep)[9]
  • Stress axisno data
  • Testosterone axisno data
  • Endocannabinoidsno data
  • Autophagy · senescenceno data
  • Immune systemno data
  • Lipid metabolismno data
  • Coagulation · fibrinolysisno data
  • Methylationno data

Routes of administration and bioavailability

How much of a compound reaches the blood or target tissue depends on the route into the body and on the dosage form. All routes of administration explained

  • Oral (swallowed) · Citrate

    higher than oxide (urine, serum); absolute fraction not verified

    Readily soluble [3]; higher urinary excretion and serum levels than after oxide in four human studies [3][4][5][6], one of them manufacturer-funded [5]. According to a systematic review, organic salts are overall more available than inorganic ones [7]; in a rat study, however, poorly available [8].[4][6]

    Human, randomised

  • Oral (swallowed) · Citrate in bowel preparation (with sodium picosulfate)

    Laxative use before colonoscopies; temporarily elevated serum values [13]. In the migraine study, diarrhea was the most common side effect [11].

    Human, randomised

Human studies

  • Comparison of citrate, amino acid chelate, oxide

    RCT, double-blind, placebo-controlled, parallel · healthy · n = 46 · 60 days

    Measured: Magnesium in urine, serum, erythrocytes, saliva

    Result: Citrate highest serum level acutely (p = 0.026) and after 60 days (p = 0.006); oxide not different from placebo.[4]

    Human, randomised

  • Citrate vs. oxide after saturation, crossover

    randomized, open, crossover, single dose; funded by the manufacturer · healthy (men) · n = 20 · Single doses after a saturation phase

    Measured: Magnesium in 24-hour urine

    Result: On average 0.565 mmol more after citrate (95% CI 0.212–0.918; p = 0.0034); serum higher at several time points.[5]

    Human, randomised

  • Citrate vs. oxide after saturation

    Single dose after a saturation phase · healthy (men) · n = 14 · 5 days of saturation, then single doses

    Measured: Magnesium in 24-hour urine and plasma

    Result: Urinary rise significant only after citrate; plasma higher than after oxide at 4 and 8 hours.[6]

    Human, non-randomised

  • Sleep and inflammation in older adults

    RCT, double-blind, placebo-controlled · healthy (51–85 years, poor sleep) · n = 100 · 7 weeks

    Measured: PSQI, magnesium status, CRP

    Result: PSQI improved equally in both groups; CRP lowered only with an elevated baseline value.[9]

    Human, randomised

  • Migraine prophylaxis

    RCT, double-blind, placebo-controlled, multicenter · Patients: migraine · n = 81 · 12 weeks

    Measured: Attack frequency

    Result: −41.6% vs. −15.8% (p < 0.05); diarrhea 18.6%.[11]

    Human, randomised

  • Nocturnal calf cramps, crossover

    RCT, double-blind, placebo-controlled, crossover · healthy (volunteers with regular calf cramps) · n = 46 · 6 weeks each of citrate and placebo

    Measured: Number of cramps per diary, severity, duration, subjective efficacy

    Result: Trend toward fewer cramps (p = 0.07), marked period effect (p = 0.008); severity and duration equal; subjectively helpful 78 vs. 54% (p = 0.03).[16]

    Human, randomised

  • Nocturnal calf cramps, crossover (Buenos Aires)

    RCT, double-blind, placebo-controlled, crossover, placebo washout phases · healthy (adults from a university outpatient clinic with at least 6 cramps in the previous month) · n = 45 · 1 month each of citrate and placebo, 4 months in total

    Measured: Number of cramps; duration, severity, cramp-related sleep disturbance

    Result: No difference in any endpoint: 11.8 vs. 11.1 cramps (p = 0.59); period effect, everyone improved over the course; 42 completed.[19]

    Human, randomised

  • Exam anxiety in students

    RCT, double-blind, placebo-controlled (gelatin); allocation by even or odd participant number · healthy (students) · n = 122 · 5 days

    Measured: State anxiety on the evening before the first final exam (Spielberger State Anxiety Inventory, Form Y-1)

    Result: No difference from placebo (p = 0.69), also not depending on pre-existing exam anxiety; 147 enrolled, 25 without questionnaire not evaluated; no side effects reported.[20]

    Human, randomised

Risks and warnings

  • Diarrhea and gastrointestinal complaints

    In the migraine study, diarrhea in 18.6% and stomach irritation in 4.7% [11]; across all forms, mainly gastrointestinal side effects [12].

    Human, randomised

  • Hypermagnesemia in impaired kidney function

    The kidney regulates the magnesium balance [1]. Hypermagnesemia has been described with magnesium-containing laxatives, mainly in older people and with impaired kidney function; in the bowel preparation study, values stayed below critical concentrations even with mild to moderate kidney impairment and normalized quickly [13].

    Human, randomised

Interactions

  • Tetracyclines and fluoroquinolones: Polyvalent cations such as Mg2+ form chelates with these antibiotics and reduce their absorption; shown for magnesium-containing antacids [15]. Not studied specifically for citrate.
  • Bisphosphonates: Same chelate mechanism according to prescribing information, quantitative data lacking [15].

Fact check: common claims

  • supported

    “Magnesium citrate is absorbed better than magnesium oxide”

    Consistent across several human studies with urine and serum measurements [3][4][5][6], one of them funded by the manufacturer [5].

  • not supported

    “Citrate is the most available form of magnesium overall”

    Only the advantage over oxide is documented; compared with an amino acid chelate, only the serum level was higher [4]. No comparison with glycinate or threonate has been made in humans, and in a rat study citrate performed poorly [8].

  • partly supported

    “Magnesium citrate prevents migraine”

    One RCT with 81 people from 1996 showed fewer attacks than under placebo [11]; a physiological review lists migraine among the applications in which magnesium was beneficial [1]. No more recent large studies specifically with citrate were found.

  • not supported

    “Magnesium citrate helps against nocturnal calf cramps”

    Two small crossover RCTs with citrate found no significant effect on the number of cramps: only a trend (p = 0.07) [16] and no difference (p = 0.59) [19], respectively; according to the Cochrane review across all forms, no relevant benefit of magnesium in older people [12].

  • supported

    “Magnesium citrate has a laxative effect”

    Used in bowel preparations [13]; diarrhea was the most common side effect in the migraine study [11].

Pharmacokinetics

Absorption
By mouth; readily soluble, higher urinary excretion than after oxide [3][5][6].
Half-life
Cannot meaningfully be stated for an endogenous mineral; not verified.
Metabolism
Citrate is metabolized, magnesium is excreted via the kidney [1].
Entry into the brain
No evidence of form-specific accumulation in the human brain.

Legal status

Germany
Also a medicinal substance: AMIce lists marketable medicinal products for human use containing magnesium citrate as the active substance (retrieved October 24, 2026) [21]; as a mineral compound under Annex II of Directive 2002/46/EC, it is permitted in food supplements [17].
EU
Annex II Part B of Directive 2002/46/EC (“magnesium salts of citric acid”); thus authorized as a magnesium source in food supplements [17].
USA
Not verified.
Other countries
Used as a component of bowel preparations before colonoscopies in clinical studies [13]; legal status not checked.

Authorised EU health claims

EU claim authorised An authorised health claim is a legal statement about the nutrient, not about this form, and not a level of evidence. The evidence for this form is reported separately under the main claim and in the human studies.

  • “contributes to normal muscle function”

    Nutrient
    Magnesium
    Legal basis
    Regulation (EU) No 432/2012[18]
    Reading
    legally permitted for magnesium in general, no statement about magnesium citrate; for calf cramps with citrate, see the promise “Fewer muscle cramps” (no benefit in two RCTs)

  • “contributes to normal psychological function”

    Nutrient
    Magnesium
    Legal basis
    Regulation (EU) No 432/2012[18]
    Reading
    legally permitted for magnesium in general, no statement about magnesium citrate; for anxiety and stress with citrate, see the promise “Stress ↓, less anxiety” (no benefit in one RCT)

Related compounds

Magnesiumoxidother form (German only)Magnesium L-threonateother formMagnesiummalatother form (German only)Magnesiumcarbonatother form (German only)

Open questions

  • Is citrate more available than glycinate or other organic salts in healthy people with saturated stores?
  • Can the migraine finding from 1996 be confirmed in larger, independent studies?
  • Why do rat studies contradict the human data on the availability of citrate?

References

  1. de Baaij JH, Hoenderop JG, Bindels RJ. Magnesium in man: implications for health and disease. Physiol Rev. 2015;95(1):1–46. doi:10.1152/physrev.00012.2014 · PubMed
  2. Nowak L, Bregestovski P, Ascher P, Herbet A, Prochiantz A. Magnesium gates glutamate-activated channels in mouse central neurones. Nature. 1984;307(5950):462–5. doi:10.1038/307462a0 · PubMed
  3. Lindberg JS, Zobitz MM, Poindexter JR, Pak CY. Magnesium bioavailability from magnesium citrate and magnesium oxide. J Am Coll Nutr. 1990;9(1):48–55. doi:10.1080/07315724.1990.10720349 · PubMed
  4. Walker AF, Marakis G, Christie S, Byng M. Mg citrate found more bioavailable than other Mg preparations in a randomised, double-blind study. Magnes Res. 2003;16(3):183–91. PubMed
  5. Kappeler D, Heimbeck I, Herpich C, Naue N, Höfler J, Timmer W, et al. Higher bioavailability of magnesium citrate as compared to magnesium oxide shown by evaluation of urinary excretion and serum levels after single-dose administration in a randomized cross-over study. BMC Nutr. 2017;3:7. doi:10.1186/s40795-016-0121-3
  6. Werner T, Kolisek M, Vormann J, Pilchova I, Grendar M, Struharnanska E, et al. Assessment of bioavailability of Mg from Mg citrate and Mg oxide by measuring urinary excretion in Mg-saturated subjects. Magnes Res. 2019;32(3):63–71. PubMed
  7. Pardo MR, Garicano Vilar E, San Mauro Martín I, Camina Martín MA. Bioavailability of magnesium food supplements: a systematic review. Nutrition. 2021;89:111294. doi:10.1016/j.nut.2021.111294 · PubMed
  8. Uysal N, Kizildag S, Yuce Z, Guvendi G, Kandis S, Koc B, et al. Timeline (bioavailability) of magnesium compounds in hours: which magnesium compound works best? Biol Trace Elem Res. 2019;187(1):128–36. doi:10.1007/s12011-018-1351-9 · PubMed
  9. Nielsen FH, Johnson LK, Zeng H. Magnesium supplementation improves indicators of low magnesium status and inflammatory stress in adults older than 51 years with poor quality sleep. Magnes Res. 2010;23(4):158–68. PubMed
  10. Mah J, Pitre T. Oral magnesium supplementation for insomnia in older adults: a systematic review & meta-analysis. BMC Complement Med Ther. 2021;21(1):125. doi:10.1186/s12906-021-03297-z · PubMed
  11. Peikert A, Wilimzig C, Köhne-Volland R. Prophylaxis of migraine with oral magnesium: results from a prospective, multi-center, placebo-controlled and double-blind randomized study. Cephalalgia. 1996;16(4):257–63. doi:10.1046/j.1468-2982.1996.1604257.x · PubMed
  12. Garrison SR, Korownyk CS, Kolber MR, Allan GM, Musini VM, Sekhon RK, et al. Magnesium for skeletal muscle cramps. Cochrane Database Syst Rev. 2020;9(9):CD009402. doi:10.1002/14651858.CD009402.pub3 · PubMed
  13. Bertiger G, Jones E, Dahdal DN, Marshall DC, Joseph RE. Serum magnesium concentrations in patients receiving sodium picosulfate and magnesium citrate bowel preparation: an assessment of renal function and electrocardiographic conduction. Clin Exp Gastroenterol. 2015;8:215–24. doi:10.2147/CEG.S79216 · PubMed
  14. Boyle NB, Lawton C, Dye L. The effects of magnesium supplementation on subjective anxiety and stress – a systematic review. Nutrients. 2017;9(5):429. doi:10.3390/nu9050429 · PubMed
  15. Ogawa R, Echizen H. Clinically significant drug interactions with antacids: an update. Drugs. 2011;71(14):1839–64. doi:10.2165/11593990-000000000-00000 · PubMed
  16. Roffe C, Sills S, Crome P, Jones P. Randomised, cross-over, placebo controlled trial of magnesium citrate in the treatment of chronic persistent leg cramps. Med Sci Monit. 2002;8(5):CR326–30. PubMed
  17. Richtlinie 2002/46/EG des Europäischen Parlaments und des Rates vom 10. Juni 2002 zur Angleichung der Rechtsvorschriften der Mitgliedstaaten über Nahrungsergänzungsmittel. ABl. L 183 vom 12.7.2002, S. 51. Konsolidierte Fassung vom 26.11.2025 (CELEX 02002L0046-20251126).
  18. Verordnung (EU) Nr. 432/2012 der Kommission vom 16. Mai 2012 zur Festlegung einer Liste zulässiger anderer gesundheitsbezogener Angaben über Lebensmittel als Angaben über die Reduzierung eines Krankheitsrisikos sowie die Entwicklung und die Gesundheit von Kindern. ABl. L 136 vom 25.5.2012, S. 1. Konsolidierte Fassung vom 20.08.2025 (CELEX 02012R0432-20250820).
  19. Frusso R, Zárate M, Augustovski F, Rubinstein A. Magnesium for the treatment of nocturnal leg cramps: a crossover randomized trial. J Fam Pract. 1999;48(11):868–71. PubMed
  20. Gendle MH, O'Hara KP. Oral magnesium supplementation and test anxiety in university undergraduates. J Artic Support Null Hypothesis. 2015;11(2):21–30. Verfügbar unter: https://www.jasnh.com/pdf/Vol11-No2-article2.pdf
  21. Bundesinstitut für Arzneimittel und Medizinprodukte. AMIce – Arzneimittel-Informationssystem, öffentlicher Teil [Datenbank]. Suche Stoffname „Magnesiumcitrat“ [zitiert 24.10.2026]. Verfügbar unter: https://portal.bfarm.de/amguifree/
How this profile was checked

Last reviewed: 2026-10-24. All sources with a DOI or PMID were resolved automatically via Crossref or doi.org and PubMed.

Translated from the German profile (version of 2026-10-24); translation checked on 2026-10-26.

Checked

  • DOIs via Crossref and PMIDs via PubMed (checking script); [5] is not listed in PubMed, DOI checked via Crossref; for [4], [6] and [9] (Magnes Res), Crossref provides no DOI, hence PMID only.
  • Checked against the abstracts: solubility 55% and 43%, higher urinary rise after citrate [3]; 46 healthy people, p = 0.033, 0.026, 0.006, oxide like placebo [4]; 20 men, 0.565 mmol (CI 0.212–0.918; p = 0.0034) [5]; 14 men, plasma higher at 4 and 8 h [6]; 14 studies, organic better [7]; rats: citrate and oxide lowest availability [8]; 100 older adults, PSQI improved in both groups, CRP [9]; three RCTs, 151 people, time to fall asleep −17.36 min, low quality [10]; 81 people, −41.6 vs. −15.8%, diarrhea 18.6%, stomach irritation 4.7% [11]; Cochrane [12]; 10% above normal, normalization in 24–48 h [13]; anxiety review [14]; chelate interactions [15]; migraine among the applications with benefit according to the abstract [1].
  • On the publisher's page of [5]: funding by Verla-Pharm Arzneimittel GmbH & Co. KG, open crossover design.
  • In the full text of [10]: included formulations magnesium oxide and magnesium citrate.
  • ClinicalTrials.gov: 240 hits for “magnesium citrate” (October 23, 2026).
  • October 24, 2026 (rule decisions K1–K8): Annex II Part B of Directive 2002/46/EC (CELEX 02002L0046-20251126, Cellar XHTML) contains “magnesium salts of citric acid.” Wording of the two magnesium claims in Regulation (EU) No 432/2012, base version (CELEX 32012R0432) and consolidated version of August 20, 2025 (CELEX 02012R0432-20250820), found unchanged.
  • Form-specific check (K2): abstract [9] confirms magnesium citrate (placebo sodium citrate). Abstract [16] (PubMed, Roffe 2002): citrate, 29 + 17 people, p = 0.07, period effect p = 0.008, 78 vs. 54% (p = 0.03), diarrhea. Full text [14] (PMC5452159): only citrate study Gendle and O’Hara 2015 (RCT, 122 students, 5 days, no significant difference); in the text of the review: “no effects of citrate … have been demonstrated.”
  • Re-check October 24, 2026: abstract [19] (PubMed, Frusso 1999): magnesium citrate, randomized, double-blind, placebo-controlled, crossover; 93 in the placebo run-in phase, 45 randomized, 42 completed; no significant differences in any endpoint, 11.1 (placebo) vs. 11.8 (magnesium) cramps, P = 0.59; significant period effect. Thus two form-specific RCTs, both without a significant effect on the number of cramps.
  • Full text [20] (PDF of the publisher's page jasnh.com, read October 24, 2026): magnesium citrate versus gelatin placebo, double-blind, 147 enrolled, 122 evaluated (25 without questionnaire), 5 days, SSAI on the evening before the first exam, treatment p = 0.69, interaction with WTAS group p = 0.75; no side effects reported; funding by the Honors Program of Elon University. Allocation was by even or odd participant number. Not listed in PubMed, no DOI.
  • Legal status (G6) on October 24, 2026: AMIce (public part, BfArM; substance name “Magnesiumcitrat,” active substance only, human medicinal product, marketable, end masking): 11 hits, including combinations, homeopathics, pharmacy preparations and parallel imports [21]. Prescribing and patient information not read.
  • Precision flags (m004, implemented by Claude on October 26, 2026, for confirmation by Tilman): “Fewer muscle cramps” → “kleine_studien”: [16] n = 46 (29 + 17), [19] n = 45 randomized (per abstract); [12] does not count according to the rationale.

Not verified

  • Legal status in the US not checked in registers.
  • Whether the authors of [6] (including NuOmix Research) have ties to manufacturers was not checked.
  • Which forms of magnesium the studies in the Cochrane review [12] used and whether [16] and [19] are included in it was not checked in detail (full text not freely accessible).
  • Whether the laxative effect in [13] is attributable to citrate or picosulfate cannot be told from the combination.

No dosages, no sources of supply. This information does not replace medical advice.

Spotted an error or missing something?

Request a compound, suggest an improvement or report an error. Every message is read.

Type of message

The website stores nothing. The button opens your email app with a pre-filled message.