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Magnesium Caps 400 mg

NOW
4.8
★ ★ ★ ★ ★
(33203 ratings)
Magnesium 400 mg
Product Image
Score79
One capsule, 400 mg, 180 servings, and low cost make this highly practical. The unknown oxide share and digestive tolerance are the key compromises.
How scoring works
Quantity:180 Capsule(s) • (180 servings)
Goals:
General Health
Stress Relief
Energy
Bone Health
Cardiovascular Support
Heart Health
Digestive Health
Fitness

Score 79

One capsule, 400 mg, 180 servings, and low cost make this highly practical. The unknown oxide share and digestive tolerance are the key compromises.
How scoring works
$13.90($0.07 per serving)
Vitacost
$ 15.75
Daily Vita
$ 13.90
Pure Formulas
$ 14.27
iHerb
$ 14.69
Walmart
$ 14.18
Report prices

Analysis

One capsule supplies 400 mg of magnesium from citrate, aspartate, and oxide. The single-capsule format and 180 servings are unusually convenient for such a substantial amount.

Citrate and aspartate add useful form diversity, while oxide is less well absorbed and may contribute more to bowel effects. The label does not state the proportion supplied by each source.

Very low serving cost creates strong value for users who tolerate the formula. The product remains a focused magnesium supplement rather than broad support for every listed goal.

Who is it for
  • Budget-conscious adults seeking high-dose magnesium
  • Users who prefer one capsule
  • People who want a long supply
Best for
  • Low-cost magnesium support
  • Single-capsule convenience
  • A 180-serving supply

Pros

  • Provides 400 mg of magnesium
  • Includes citrate and aspartate
  • Uses one capsule per serving
  • Offers 180 low-cost servings

Cons

  • Includes magnesium oxide
  • Does not disclose form proportions
  • The amount may exceed routine needs
  • Full excipients are not shown

Warnings

  • The 400 mg magnesium serving may cause diarrhea, cramping, or nausea, especially when taken at once.
  • Reduced kidney function can impair magnesium clearance, so regular supplemental use requires medical guidance in that situation.
  • Magnesium can reduce absorption of levothyroxine, bisphosphonates, and certain antibiotics; follow the medicine-specific spacing interval.

Nutrient quality

79 High impact

The magnesium amount is meaningful, but form quality is mixed. A high serving raises digestive-tolerance concerns for general use.

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Ingredient transparency

74 High impact

The total amount is listed, but the contribution from each form remains unclear. Complete directions and inactive ingredients are not supplied.

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Customer satisfaction

72 High impact

The average customer rating is very strong. An exceptionally large rating base makes the average highly dependable, while specific review experiences were not supplied.

.

Value for money

91 Highest impact

Serving economics are highly favorable for the supplied amount. Form or label limitations keep value moderate.

.
Report analysis

Goals

General Health
General Health
Impact
Highest effect
A Goal FitB+ Strength of SupportC CoverageB+ Formula Quality
Magnesium · 400 mg

A substantial magnesium amount supports energy metabolism, nerve signaling, and muscle function. Citrate and aspartate improve the blend, while magnesium oxide lowers its expected absorption quality.

The focused formula provides strong depth for one foundational mineral but little breadth beyond it. The full serving may loosen stools or cause digestive discomfort in sensitive users.

Study evidence
Magnesium Supportive 114 studies
Stress Relief
Stress Relief
Impact
High effect
B+ Goal FitB+ Strength of SupportC- CoverageB+ Formula Quality
Magnesium · 400 mg

Magnesium at 400 mg may support nervous-system regulation and physical relaxation, especially when intake is low. The focused formula supplies a meaningful elemental amount.

Citrate and aspartate are paired with poorly absorbed magnesium oxide. limits how confidently absorption and tolerance can be judged. The substantial supplemental amount may cause loose stools or abdominal discomfort.

Study evidence
Magnesium Supportive 13 studies
Energy
Energy
Impact
High effect
B Goal FitB Strength of SupportC- CoverageA- Formula Quality
Magnesium · 400 mg

The clearly stated magnesium amount is high enough to support ATP-dependent metabolism when intake is low. Citrate and aspartate improve the blend, but magnesium oxide lowers its overall absorption potential.

The single-mineral design does not address alertness, mitochondrial cofactors beyond magnesium, or stress resilience. The high supplemental amount may cause loose stools or abdominal discomfort, particularly because oxide can remain in the digestive tract.

Study evidence
Magnesium Supportive 4 studies
Bone Health
Bone Health
Impact
High effect
B Goal FitB+ Strength of SupportD+ CoverageB- Formula Quality
Magnesium · 400 mg

A fully disclosed magnesium amount supports bone mineral structure and vitamin D activation. Citrate and aspartate improve the blend, but magnesium oxide lowers its absorption potential.

The focused formula provides useful depth for magnesium without calcium, vitamin D, vitamin K, or collagen support. Its simple design avoids unrelated additions and suits a targeted mineral gap.

Study evidence
Magnesium Supportive 48 studies
Cardiovascular Support
Cardiovascular Support
Impact
High effect
B+ Goal FitC+ Strength of SupportC- CoverageA- Formula Quality
Magnesium · 400 mg

Magnesium supports vascular relaxation and the electrical stability of heart cells, making it relevant to blood pressure and rhythm. The 400 mg serving is substantial, though the formula relies partly on forms with uneven absorption.

The single-mineral focus does not address lipids, nitric oxide production, or cardiac energy. Supplemental magnesium at this amount can cause diarrhea or abdominal cramping, especially when oxide or carbonate is present.

Study evidence
Magnesium Supportive 123 studies
Heart Health
Heart Health
Impact
High effect
C+ Goal FitB+ Strength of SupportD+ CoverageA Formula Quality
Magnesium · 400 mg

Magnesium supports vascular tone, blood-pressure regulation, and normal heart rhythm when intake is low. A single-mineral product does not address lipids, nitric oxide, or cellular energy.

The 400 mg amount is substantial, but oxide is among the listed forms and repeated totals do not reveal each form’s contribution. High supplemental magnesium may cause diarrhea or abdominal discomfort.

Study evidence
Magnesium Supportive 158 studies

Ingredients

IngredientAmount per serving
Magnesium (Magnesium Aspartate, Magnesium Citrate, Magnesium Oxide)
 400 mg
Gluten Free Adults 18–50 Vegan Kosher Dairy Free Vegetarian
Report overview
Magnesium (Magnesium Aspartate, Magnesium Citrate, Magnesium Oxide) · 400 mg OverallScore65
D- Active Ingredient Quality & BioavailabilityA Dose, Safety & Label TransparencyC Value
+1

The magnesium blend combines better-absorbed forms with oxide, creating mixed absorption potential. The elemental amount is clearly disclosed and falls within the standard therapeutic range. The focused formula lacks added cofactors, while its cost remains relatively economical.

View ingredientView products
Loading alternative details
91 Performance

Krebs Magnesium Potassium Complex

Nature's Way
<p>Magnesium lysinate and malate provide favorable forms at a useful 250 mg amount, with 95 mg potassium citrate for broader mineral support. Compared with the original 400 mg multi-form blend, the form disclosure is clearer and the dose is less aggressive for many users.</p>
88 Performance

Magnesium Bisglycinate Powder

NOW
<p>The pure powder provides 250 mg magnesium bisglycinate in a well-absorbed, adjustable form. Compared with the original 400 mg multi-form blend, the single named form is easier to assess and may be gentler on digestion.</p>
85 Performance

Magnesium Bisglycinate Chelate

Healthy Origins
<p>The clean powder uses TRAACS magnesium bisglycinate at a practical 200 mg elemental amount. Compared with the original 400 mg multi-form blend, it prioritizes absorption quality and moderate dosing, although it may provide less total magnesium.</p>
83 Budget

Magnesium Citrate Pure Powder

Best Naturals
<p>The lower-cost powder provides 210 mg magnesium citrate in an adjustable serving. Compared with the original 400 mg multi-form blend, citrate is clearly identified and generally useful for routine repletion, though it may loosen stools.</p>
80 Budget

Magnesium Caps 500 mg

Life Extension
<p>The lower-cost blend supplies 500 mg magnesium across citrate, succinate, glycinate, and oxide sources. It offers a substantial amount for the cost, but oxide lowers average absorption quality and the high serving may cause diarrhea or cramping compared with the original 400 mg multi-form blend.</p>
84 Budget

Potassium + Magnesium

Nutricost
<p>A third low-cost candidate, though not cheaper than the original, supplies 210 mg magnesium citrate with 99 mg potassium citrate. It offers clear mineral forms and practical value, although its magnesium amount may be lower than the original 400 mg multi-form blend.</p>
85 Value

Magnesium Bisglycinate 200 mg

Natural Factors
<p>The focused powder combines 200 mg magnesium bisglycinate with a moderate serving cost and a nonaggressive dose. Compared with the original 400 mg multi-form blend, the clearly named form improves quality-to-cost balance while reducing the chance of dose-related digestive discomfort.</p>
85 Value

Cal/Mag 500 mg/250 mg

NaturesPlus
<p>The formula pairs 250 mg chelated magnesium with 500 mg chelated calcium in an economical serving. It adds useful bone-mineral breadth and clear forms compared with the original 400 mg multi-form blend, though calcium may be unnecessary for users seeking magnesium alone.</p>
81 Value

Ultra-Mag

Source Naturals
<p>The broad blend supplies 400 mg magnesium from citrate, glycinate, malate, succinate, and taurinate forms at a favorable serving cost. Form diversity improves practical value compared with the original 400 mg multi-form blend, while the high amount and 30 mg vitamin B6 may reduce suitability for long-term routine use.</p>
Report alternatives

Sources

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

  1. 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
  2. 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
  3. 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
  4. 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
  5. 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
  6. 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
  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. 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
  9. 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
  10. 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
  11. 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
  12. 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
  13. 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
  14. 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
  15. 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
  16. 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
  17. 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 Fitness forMagnesium
  18. Red blood cell magnesium and chronic fatigue syndrome.
    Cox IM; Campbell MJ; Dowson D · Lancet (London, England) · 1991
    Randomized trial32 participantsEnergy forMagnesium
  19. Exercise, magnesium and immune function.
    Laires MJ; Monteiro C · Magnesium research · 2008
    Narrative reviewEnergy forMagnesium
  20. Dietary Magnesium May Be Protective for Aging of Bone and Skeletal Muscle in Middle and Younger Older Age Men and Women: Cross-Sectional Findings from the UK Biobank Cohort.
    Welch AA; Skinner J; Hickson M · Nutrients · 2018
    Cross-sectional study156,575 participantsFitness forMagnesium
  21. Dietary Magnesium Is Positively Associated With Skeletal Muscle Power and Indices of Muscle Mass and May Attenuate the Association Between Circulating C-Reactive Protein and Muscle Mass in Women.
    Welch AA; Kelaiditi E; Jennings A; Steves CJ; Spector TD; MacGregor A · Journal of bone and mineral research : the official journal of the American Society for Bone and Mineral Research · 2016
    Cross-sectional study2,570 participantsFitness forMagnesium
  22. Nutritional intake as a determinant of high-speed resistance and multicomponent training efficacy on strength in older women at risk of sarcopenia. A randomized clinical trial.
    Polo-Ferrero L; Recio-Rodriguez JI; González-Manzano S; Martín-Vallejo J; Barbero-Iglesias FJ; Montero-Errasquín B; Cruz-Jentoft AJ; Méndez-Sánchez R · Clinical nutrition (Edinburgh, Scotland) · 2025
    Randomized trial80 participantsFitness forMagnesium
  23. Minerals and Sarcopenia in Older Adults: An Updated Systematic Review.
    van Dronkelaar C; Fultinga M; Hummel M; Kruizenga H; Weijs PJM; Tieland M · Journal of the American Medical Directors Association · 2023
    Systematic review45 studies pooledFitness forMagnesium
  24. 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
  25. 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
  26. 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
  27. 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
  28. 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
  29. 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
  30. 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
  31. 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
  32. 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
  33. 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
  34. 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
  35. 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
  36. 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
  37. 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
  38. 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
  39. 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
  40. 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
  41. 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