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KalmAssure Magnesium Capsules 420 mg

4.7
★ ★ ★ ★ ★
(2002 ratings)
Magnesium 420 mg
Product Image
Score84
A transparent high-dose magnesium citrate capsule for users who tolerate its digestive effect. Four capsules and only thirty servings reduce convenience.
How scoring works
Capsule
Quantity:120 Capsule(s) • (30 servings)
Goals:
General Health
Energy
Digestive Health
Sleep Support
Stress Relief
Cardiovascular Support
Heart Health
Bone Health
Testosterone Support

Score 84

A transparent high-dose magnesium citrate capsule for users who tolerate its digestive effect. Four capsules and only thirty servings reduce convenience.
How scoring works
$11.86($0.39 per serving)
Vitacost
$ 11.97
iHerb
$ 11.86
Amazon
$ 13.95
Walmart
$ 13.62
Pure Formulas
$ 11.86
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Analysis

Magnesium citrate supplies a substantial amount for normal muscle, nerve, energy, bone, and cardiovascular functions. The single-active design makes the form and amount easy to assess.

Citrate is reasonably absorbable and also has an osmotic digestive effect. At 420 mg, that bowel effect may dominate for sensitive users or anyone who does not need stool-softening support.

The four-capsule serving fits users who want adjustable citrate dosing, but only thirty full servings are provided. Lower intake may be more comfortable for routine magnesium support.

Who is it for
  • Adults seeking magnesium citrate
  • Users wanting bowel-motility support
  • People able to adjust a four-capsule serving
Best for
  • Digestive motility
  • General magnesium intake
  • Muscle and nerve nutrition

Pros

  • Clear citrate form
  • Substantial elemental amount
  • Focused single-active formula
  • Adjustable capsule count

Cons

  • Four capsules per serving
  • Only thirty servings
  • High laxative potential
  • No supporting cofactors

Warnings

  • The 420 mg citrate amount may cause diarrhea or abdominal cramping.
  • Start below the full serving if bowel tolerance is uncertain.
  • High-dose magnesium requires clinician review when kidney function is impaired.

Nutrient quality

82 Highest impact

Citrate provides useful absorption and a full supplemental amount. The high amount increases the chance of digestive intolerance.

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Ingredient transparency

89 Highest impact

The active form and elemental amount are clearly identified. Complete use directions and inactive ingredients are not included in the supplied data.

.

Customer satisfaction

72 High impact

The supplied average rating is strong and backed by a large review pool. No review text is available to assess repeated complaints or purpose-specific experiences.

.

Value for money

90 Highest impact

Useful citrate and a full amount support strong practical value. The favorable serving cost compares well within the magnesium category.

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Goals

General Health
Impact
Highest effect
A+ Goal FitA- Strength of SupportC+ CoverageA Formula Quality
Magnesium · 420 mg

Magnesium supports energy production, muscle function, and nervous system regulation. Magnesium citrate has moderate absorption, and the clearly stated 420 mg amount reaches the upper end of a useful supplemental range.

The single-mineral capsule provides focused depth without broader nutritional coverage. Taking the full serving at once may cause loose stools or abdominal cramping in sensitive users.

Study evidence
Magnesium Supportive 114 studies
Energy
Impact
Highest effect
A Goal FitA- Strength of SupportC CoverageA+ Formula Quality
Magnesium · 420 mg

Magnesium citrate provides a substantial elemental amount for ATP-dependent enzymes, muscles, and nerves. The simple capsule formula is transparent and moderately well absorbed.

Four capsules are required for a full serving, which may reduce convenience. The full citrate amount can also cause loose stools or abdominal cramping in sensitive users.

Study evidence
Magnesium Supportive 4 studies
Digestive Health
Impact
Highest effect
A Goal FitA- Strength of SupportC- CoverageA+ Formula Quality
Magnesium · 420 mg

Magnesium citrate directly supports stool softening by drawing water into the bowel and may help occasional constipation. The clearly stated 420 mg serving provides substantial strength for that narrow use.

The streamlined formula does not address digestive enzymes, the gut lining, or the microbiome. The full serving may cause loose stools or abdominal cramping, especially when taken at once.

Study evidence
Magnesium Supportive 50 studies
Sleep Support
Impact
Highest effect
B+ Goal FitA- Strength of SupportC CoverageA+ Formula Quality
Magnesium · 420 mg

Magnesium citrate supports nervous-system relaxation and may help sleep when magnesium intake is inadequate. It does not directly regulate circadian timing or provide a dedicated calming neurotransmitter ingredient.

The 420 mg elemental amount is clearly disclosed and provides strong depth for the mineral pathway. The 420 mg magnesium citrate amount may cause loose stools or abdominal cramping, especially when taken at once.

Study evidence
Magnesium Supportive 23 studies
Stress Relief
Impact
High effect
C+ Goal FitA Strength of SupportC- CoverageA Formula Quality
Magnesium · 420 mg

Magnesium citrate provides foundational support for relaxation and normal nervous-system function. It is a focused mineral product without adaptogen or direct calming-amino-acid coverage.

The 420 mg amount and citrate form are fully disclosed and provide strong dose clarity. Magnesium citrate at this amount may cause loose stools or abdominal discomfort, especially in sensitive users.

Study evidence
Magnesium Supportive 13 studies
Cardiovascular Support
Impact
High effect
B+ Goal FitB- Strength of SupportC- CoverageA Formula Quality
Magnesium · 420 mg

Magnesium provides a relevant route to cardiovascular support. The disclosed amount appears meaningful for that focused role.

The formula remains narrow rather than comprehensive. Vitamin K can oppose warfarin and related vitamin-K-antagonist medicines, so the intake should remain medically coordinated and consistent.

Study evidence
Magnesium Supportive 123 studies

Ingredients

IngredientAmount per serving
Magnesium (Magnesium Citrate)
420 mg
Gluten Free Adults 18–50 Vegan Dairy Free No Allergies Vegetarian
Report overview
D Active Ingredient Quality & BioavailabilityA Dose, Safety & Label TransparencyA- Value
+1

Magnesium citrate offers moderate absorption and is a practical option for people who tolerate it. The clearly stated amount falls within the preferred supplemental range. The simple formula avoids competing minerals but adds no targeted cofactor. Its below-median serving cost creates favorable value.

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Sources

Published studies used for the product analysis and the top-ranked studies for each ingredient and goal.

  1. Magnesium-L-threonate improves sleep quality and daytime functioning in adults with self-reported sleep problems: A randomized controlled trial.
    Hausenblas HA; Lynch T; Hooper S; Shrestha A; Rosendale D; Gu J · Sleep medicine: X · 2025
    Randomized trial80 participantsEnergy forMagnesium
  2. Red blood cell magnesium and chronic fatigue syndrome.
    Cox IM; Campbell MJ; Dowson D · Lancet (London, England) · 1991
    Randomized trial32 participantsEnergy forMagnesium
  3. Long-term magnesium supplementation improves arterial stiffness in overweight and obese adults: results of a randomized, double-blind, placebo-controlled intervention trial.
    Joris PJ; Plat J; Bakker SJ; Mensink RP · The American journal of clinical nutrition · 2017
    Randomized trial52 participantsHeart Health forMagnesium
  4. Effects of Magnesium Citrate, Magnesium Oxide, and Magnesium Sulfate Supplementation on Arterial Stiffness: A Randomized, Double-Blind, Placebo-Controlled Intervention Trial.
    Schutten JC; Joris PJ; Groendijk I; Eelderink C; Groothof D; van der Veen Y; Westerhuis R; Goorman F; Danel RM; de Borst MH; Bakker SJL · Journal of the American Heart Association · 2022
    Randomized trial164 participantsHeart Health forMagnesium
  5. An update on magnesium and bone health.
    Rondanelli M; Faliva MA; Tartara A; Gasparri C; Perna S; Infantino V; Riva A; Petrangolini G; Peroni G · Biometals : an international journal on the role of metal ions in biology, biochemistry, and medicine · 2022
    Narrative reviewBone Health forMagnesium
  6. Magnesium intake, bone mineral density, and fractures: results from the Women's Health Initiative Observational Study.
    Orchard TS; Larson JC; Alghothani N; Bout-Tabaku S; Cauley JA; Chen Z; LaCroix AZ; Wactawski-Wende J; Jackson RD · The American journal of clinical nutrition · 2014
    Cohort study73,684 participantsBone Health forMagnesium
  7. Magnesium and the risk of cardiovascular events: a meta-analysis of prospective cohort studies.
    Qu X; Jin F; Hao Y; Li H; Tang T; Wang H; Yan W; Dai K · PloS one · 2013
    Meta-analysis532,979 participants19 studies pooledCardiovascular Support forMagnesium
  8. Effects of long-term magnesium supplementation on endothelial function and cardiometabolic risk markers: A randomized controlled trial in overweight/obese adults.
    Joris PJ; Plat J; Bakker SJ; Mensink RP · Scientific reports · 2018
    Randomized trial52 participantsCardiovascular Support forMagnesium
  9. The effect of food, vitamin, or mineral supplements on chronic constipation in adults: A systematic review and meta-analysis of randomized controlled trials.
    van der Schoot A; Creedon A; Whelan K; Dimidi E · Neurogastroenterology and motility · 2023
    Meta-analysis787 participants8 studies pooledDigestive Health forMagnesium
  10. Diagnosis of magnesium-induced diarrhea.
    Fine KD; Santa Ana CA; Fordtran JS · The New England journal of medicine · 1991
    Clinical trial19 participantsDigestive Health forMagnesium
  11. Association between Serum Magnesium and Fractures: A Systematic Review and Meta-Analysis of Observational Studies.
    Dominguez LJ; Veronese N; Ciriminna S; Pérez-Albela JL; Vásquez-López VF; Rodas-Regalado S; Di Bella G; Parisi A; Tagliaferri F; Barbagallo M · Nutrients · 2023
    Meta-analysis119,755 participants4 studies pooledBone Health forMagnesium
  12. Bioabsorbable Magnesium-Based Materials Potential and Safety in Bone Surgery: A Systematic Review.
    Hung CH; Kwok YC; Yip J; Wong HH; Leung YY · Craniomaxillofacial trauma & reconstruction · 2025
    Systematic review386 participants8 studies pooledBone Health forMagnesium
  13. Vascularized bone grafting fixed by biodegradable magnesium screw for treating osteonecrosis of the femoral head.
    Zhao D; Huang S; Lu F; Wang B; Yang L; Qin L; Yang K; Li Y; Li W; Wang W; Tian S; Zhang X; Gao W; Wang Z; Zhang Y; Xie X; Wang J; Li J · Biomaterials · 2016
    Randomized trial48 participantsBone Health forMagnesium
  14. Sex-specific differences in the association of magnesium intake with femoral neck bone mineral density among older adults.
    Wang B; Tan X; Yao X; Zhu Z · Endocrine connections · 2025
    Cross-sectional study1,343 participantsBone Health forMagnesium
  15. Circulating and dietary magnesium and risk of cardiovascular disease: a systematic review and meta-analysis of prospective studies.
    Del Gobbo LC; Imamura F; Wu JH; de Oliveira Otto MC; Chiuve SE; Mozaffarian D · The American journal of clinical nutrition · 2013
    Meta-analysis313,041 participants16 studies pooledCardiovascular Support forMagnesium
  16. Quantitative Association Between Serum/Dietary Magnesium and Cardiovascular Disease/Coronary Heart Disease Risk: A Dose-Response Meta-analysis of Prospective Cohort Studies.
    Zhao L; Hu M; Yang L; Xu H; Song W; Qian Y; Zhao M · Journal of cardiovascular pharmacology · 2020
    Meta-analysis544,581 participants18 studies pooledCardiovascular Support Heart Health forMagnesium
  17. Comparative Efficacy of Nutraceuticals on Endothelial Function: A Systematic Review and Network Meta-Analysis.
    Norouzzadeh M; Rashedi MH; Mahdavi-Mazdeh G; Kosari A; Shahinfar H · Current atherosclerosis reports · 2026
    Meta-analysisCardiovascular Support Heart Health forMagnesium
  18. Serum magnesium, mortality, and cardiovascular disease in chronic kidney disease and end-stage renal disease patients: a systematic review and meta-analysis.
    Xiong J; He T; Wang M; Nie L; Zhang Y; Wang Y; Huang Y; Feng B; Zhang J; Zhao J · Journal of nephrology · 2020
    Meta-analysis200,934 participants20 studies pooledCardiovascular Support forMagnesium
  19. Efficacy of oral magnesium therapy in the treatment of chronic constipation in spastic cerebral palsy children: a randomized controlled trial.
    Hassanein SMA; Deifallah SM; Bastawy HA · World journal of pediatrics : WJP · 2021
    Randomized trial100 participantsDigestive Health forMagnesium
  20. Ca:Mg ratio, medium-chain fatty acids, and the gut microbiome.
    Fan L; Zhu X; Sun S; Yu C; Huang X; Ness R; Dugan LL; Shu L; Seidner DL; Murff HJ; Fodor AA; Azcarate-Peril MA; Shrubsole MJ; Dai Q · Clinical nutrition (Edinburgh, Scotland) · 2022
    Randomized trial240 participantsDigestive Health forMagnesium
  21. The Magnesium-Rich Formula for Functional Constipation in Infants: a Randomized Comparator-Controlled Study.
    Benninga MA; MENA Infant Constipation Study Group; Vandenplas Y · Pediatric gastroenterology, hepatology & nutrition · 2022
    Randomized trial286 participantsDigestive Health forMagnesium
  22. A Randomized Double-blind Placebo-controlled Trial on the Effect of Magnesium Oxide in Patients With Chronic Constipation.
    Mori S; Tomita T; Fujimura K; Asano H; Ogawa T; Yamasaki T; Kondo T; Kono T; Tozawa K; Oshima T; Fukui H; Kimura T; Watari J; Miwa H · Journal of neurogastroenterology and motility · 2022
    Randomized trial34 participantsDigestive Health forMagnesium
  23. Magnesium treatment increases gut microbiome synthesizing vitamin D and inhibiting colorectal cancer: results from a double-blind precision-based randomized placebo-controlled trial.
    Sun E; Zhu X; Ness RM; Murff HJ; Sun S; Yu C; Fan L; Azcarate-Peril MA; Shrubsole MJ; Dai Q · The American journal of clinical nutrition · 2025
    Randomized trial240 participantsDigestive Health forMagnesium
  24. Total magnesium intake and risk of frailty in older women.
    Struijk EA; Fung TT; Bischoff-Ferrari HA; Willett WC; Lopez-Garcia E · Journal of cachexia, sarcopenia and muscle · 2024
    Cohort study81,524 participantsEnergy forMagnesium
  25. Exercise, magnesium and immune function.
    Laires MJ; Monteiro C · Magnesium research · 2008
    Narrative reviewEnergy forMagnesium
  26. Perioperative systemic magnesium to minimize postoperative pain: a meta-analysis of randomized controlled trials.
    De Oliveira GS; Castro-Alves LJ; Khan JH; McCarthy RJ · Anesthesiology · 2013
    Meta-analysis1,257 participants20 studies pooledGeneral Health forMagnesium
  27. Long-term outcome after intravenous magnesium sulphate in suspected acute myocardial infarction: the second Leicester Intravenous Magnesium Intervention Trial (LIMIT-2).
    Woods KL; Fletcher S · Lancet (London, England) · 1994
    Randomized trial2,316 participantsGeneral Health forMagnesium
  28. Association of magnesium sulfate use with mortality in critically ill patients with sepsis: a retrospective propensity score-matched cohort study.
    Gu WJ; Duan XJ; Liu XZ; Cen Y; Tao LY; Lyu J; Yin HY · British journal of anaesthesia · 2023
    Cohort study10,999 participantsGeneral Health forMagnesium
  29. Hypomagnesemia and Mortality in Incident Hemodialysis Patients.
    Li L; Streja E; Rhee CM; Mehrotra R; Soohoo M; Brunelli SM; Kovesdy CP; Kalantar-Zadeh K · American journal of kidney diseases : the official journal of the National Kidney Foundation · 2016
    Cohort study9,359 participantsGeneral Health forMagnesium
  30. The effects of magnesium supplementation on abnormal uterine bleeding, alopecia, quality of life, and acne in women with polycystic ovary syndrome: a randomized clinical trial.
    Jaripur M; Ghasemi-Tehrani H; Askari G; Gholizadeh-Moghaddam M; Clark CCT; Rouhani MH · Reproductive biology and endocrinology : RB&E · 2022
    Randomized trial64 participantsGeneral Health forMagnesium
  31. Effects of magnesium supplementation on improving hyperglycemia, hypercholesterolemia, and hypertension in type 2 diabetes: A pooled analysis of 24 randomized controlled trials.
    Xu L; Li X; Wang X; Xu M · Frontiers in nutrition · 2023
    Meta-analysis1,325 participants24 studies pooledHeart Health forMagnesium
  32. The effect of lowering blood pressure by magnesium supplementation in diabetic hypertensive adults with low serum magnesium levels: a randomized, double-blind, placebo-controlled clinical trial.
    Guerrero-Romero F; Rodríguez-Morán M · Journal of human hypertension · 2009
    Randomized trial82 participantsHeart Health forMagnesium
  33. Positive effects of magnesium supplementation in metabolic syndrome.
    Kisters S; Kisters K; Werner T; Vormann J; Tokmak F; Westhoff T; Gröber U; Predel HG; Reuter H · International journal of clinical pharmacology and therapeutics · 2024
    Randomized trial54 participantsHeart Health forMagnesium
  34. Effects of magnesium and potassium supplementation on insomnia and sleep hormones in patients with diabetes mellitus.
    Khalid S; Bashir S; Mehboob R; Anwar T; Ali M; Hashim M; Waseem H; Basharat S · Frontiers in endocrinology · 2024
    Randomized trial320 participantsSleep Support forMagnesium
  35. Association of magnesium intake with sleep duration and sleep quality: findings from the CARDIA study.
    Zhang Y; Chen C; Lu L; Knutson KL; Carnethon MR; Fly AD; Luo J; Haas DM; Shikany JM; Kahe K · Sleep · 2022
    Cohort study3,964 participantsSleep Support forMagnesium
  36. Lidocaine vs. magnesium: effect on analgesia after a laparoscopic cholecystectomy.
    Saadawy IM; Kaki AM; Abd El Latif AA; Abd-Elmaksoud AM; Tolba OM · Acta anaesthesiologica Scandinavica · 2010
    Randomized trial120 participantsSleep Support forMagnesium
  37. The effect of magnesium supplementation on primary insomnia in elderly: A double-blind placebo-controlled clinical trial.
    Abbasi B; Kimiagar M; Sadeghniiat K; Shirazi MM; Hedayati M; Rashidkhani B · Journal of research in medical sciences : the official journal of Isfahan University of Medical Sciences · 2013
    Randomized trial46 participantsSleep Support forMagnesium
  38. A randomized, double-blind, placebo-controlled, multicenter study assessing the efficacy of magnesium oxide monohydrate in the treatment of nocturnal leg cramps.
    Barna O; Lohoida P; Holovchenko Y; Bazylevych A; Velychko V; Hovbakh I; Bula L; Shechter M · Nutrition journal · 2021
    Randomized trial175 participantsSleep Support forMagnesium
  39. Role of magnesium supplementation in the treatment of depression: A randomized clinical trial.
    Tarleton EK; Littenberg B; MacLean CD; Kennedy AG; Daley C · PloS one · 2017
    Randomized trial126 participantsStress Relief forMagnesium
  40. Effects of Intravenous Esketamine or Magnesium Sulfate on Early Postoperative Negative Emotions and Pain in Patients Undergoing Endoscopic Sinus Surgery: A Randomized Controlled Trial.
    Wang L; Zhou J; Liu Q; Qian K; Wang L; Xie C · Therapeutics and clinical risk management · 2026
    Randomized trial137 participantsStress Relief forMagnesium
  41. Effect of short-term magnesium supplementation on anxiety, depression and sleep quality in patients after open-heart surgery.
    Saba S; Faizi F; Sepandi M; Nehrir B · Magnesium research · 2022
    Non-randomized trial60 participantsStress Relief forMagnesium
  42. Effects of dry needling compared to magnesium infiltration in trigger points for patients with myofascial pain syndrome: a randomized controlled study in Tunisia.
    Dhouibi J; Moncer R; Kalbousi N; Gaddour M; Laayouni S; Ouanes W; Kacem B; Jemni S · Korean journal of family medicine · 2026
    Randomized trial45 participantsStress Relief forMagnesium
  43. Effect of magnesium and vitamin B6 supplementation on mental health and quality of life in stressed healthy adults: Post-hoc analysis of a randomised controlled trial.
    Noah L; Dye L; Bois De Fer B; Mazur A; Pickering G; Pouteau E · Stress and health : journal of the International Society for the Investigation of Stress · 2021
    Randomized trialStress Relief forMagnesium
  44. Magnesium and anabolic hormones in older men.
    Maggio M; Ceda GP; Lauretani F; Cattabiani C; Avantaggiato E; Morganti S; Ablondi F; Bandinelli S; Dominguez LJ; Barbagallo M; Paolisso G; Semba RD; Ferrucci L · International journal of andrology · 2012
    Cohort study399 participantsTestosterone Support forMagnesium
  45. Analysis of the relationship between the blood concentration of several metals, macro- and micronutrients and endocrine disorders associated with male aging.
    Rotter I; Kosik-Bogacka DI; Dołęgowska B; Safranow K; Kuczyńska M; Laszczyńska M · Environmental geochemistry and health · 2017
    Cross-sectional study313 participantsTestosterone Support forMagnesium
  46. Effect of magnesium supplementation in improving hyperandrogenism, hirsutism, and sleep quality in women with polycystic ovary syndrome: A randomized, placebo-controlled clinical trial.
    Gholizadeh-Moghaddam M; Ghasemi-Tehrani H; Askari G; Jaripur M; Clark CCT; Rouhani MH · Health science reports · 2024
    Randomized trial64 participantsTestosterone Support forMagnesium
  47. The effects of trace element supplementation on glycolipid metabolism in PCOS: a systematic review and meta-analysis.
    Yang L; Gao Y; Zhao W; Qi Y; Duo X; Wang H · Frontiers in nutrition · 2025
    Meta-analysis1,600 participants25 studies pooledTestosterone Support forMagnesium
  48. Effects of magnesium supplementation on testosterone levels of athletes and sedentary subjects at rest and after exhaustion.
    Cinar V; Polat Y; Baltaci AK; Mogulkoc R · Biological trace element research · 2011
    Non-randomized trial20 participantsTestosterone Support forMagnesium