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Magnesium Oxide 500 mg

4.5
★ ★ ★ ★ ★
(981 ratings)
Magnesium 500 mg
Product Image
Score70
A simple high-dose oxide formula favors affordability and bowel effects over absorption. The label amount looks strong, but systemic delivery is likely less impressive.
How scoring works
Capsule
Quantity:90 Capsule(s) • (90 servings)
Goals:
Energy
General Health
Bone Health

Score 70

A simple high-dose oxide formula favors affordability and bowel effects over absorption. The label amount looks strong, but systemic delivery is likely less impressive.
How scoring works
$9.98($0.11 per serving)
Vitacost
$ 11.79
iHerb
$ 10.99
Amazon
$ 9.99
Pure Formulas
$ 9.98
Report prices

Analysis

The product supplies 500 mg of magnesium and identifies oxide in its name, although the ingredient entry does not repeat the form. Oxide is inexpensive and compact but less efficiently absorbed than citrate, glycinate, or malate.

The high amount may support occasional bowel motility through an osmotic effect. It is less convincing for muscle, energy, bone, or cardiovascular goals that depend on predictable systemic delivery.

A one-capsule serving and short label are practical. Users prioritizing absorption or gentle daily use should look for a moderate amount from a fully disclosed chelated or organic-acid form.

Who is it for
  • Adults seeking inexpensive occasional motility support
  • Users who specifically tolerate magnesium oxide
Best for
  • Short-term stool-softening use
  • A basic one-capsule magnesium option

Pros

  • Large elemental amount
  • Simple single-mineral formula
  • Convenient one-capsule serving

Cons

  • Oxide has weak systemic absorption
  • High amount may overstate useful delivery
  • Narrow value outside motility support

Warnings

  • A 500 mg oxide serving can cause diarrhea, abdominal cramping, or urgency.
  • Magnesium can bind tetracycline or quinolone antibiotics and oral bisphosphonates, so these medicines should be taken several hours apart.
  • Impaired kidney function can reduce magnesium clearance, making a large supplemental amount less appropriate without clinical guidance.

Nutrient quality

64 Moderate impact

The supplied label data omit the magnesium form, while related information indicates poorly absorbed oxide. The magnesium amount is substantial but unlikely to deliver proportionate systemic absorption from oxide.

Ingredient transparency

73 High impact

The elemental magnesium amount is clearly stated. The product data do not name the magnesium form explicitly.

Customer satisfaction

68 High impact

The aggregate rating is strong and the available feedback volume gives it useful support. No specific review comments are supplied to assess recurring benefits or complaints.

Value for money

76 High impact

Very low routine cost improves affordability, but weak absorption limits quality value. No decorative active ingredients are included.

Report analysis

Goals

Energy
Energy
Impact
High effect
B Goal FitC Strength of SupportD+ CoverageA Formula Quality
Magnesium · 500 mg

Magnesium supports ATP-dependent enzymes and can help fatigue caused by low magnesium intake. The product title indicates magnesium oxide, while the ingredient entry does not clearly state the chemical form.

The large amount may be poorly absorbed and can cause diarrhea or cramping. Coverage remains limited to one metabolic cofactor with no alertness or stress-resilience pathway.

Study evidence
Magnesium Supportive 4 studies
General Health
General Health
Impact
High effect
A- Goal FitD Strength of SupportD CoverageB+ Formula Quality
Magnesium · 500 mg

Magnesium is a well-supported foundational mineral for energy metabolism, muscle function, and nervous-system balance. The single-capsule format provides a clearly labeled and substantial amount.

Magnesium oxide is poorly absorbed compared with citrate, glycinate, or other well-chosen forms, so the large label amount may overstate useful delivery. A 500 mg serving also carries a meaningful risk of diarrhea and abdominal cramping.

Study evidence
Magnesium Supportive 114 studies
Bone Health
Bone Health
Impact
High effect
B Goal FitC Strength of SupportD CoverageB+ Formula Quality
Magnesium · 500 mg

Magnesium supports bone mineral structure and vitamin D metabolism, so the product has a valid but narrow role. The 500 mg amount is substantial for a single-capsule supplement.

Magnesium oxide has limited absorption compared with citrate or chelated forms, which weakens the useful contribution. The large oxide amount may cause loose stools without delivering equivalent absorbed magnesium.

Study evidence
Magnesium Supportive 48 studies
Stress Relief
Stress Relief
Impact
Moderate effect
C- Goal FitC- Strength of SupportD- CoverageA Formula Quality
Magnesium · 500 mg

Magnesium can support normal nervous-system regulation and muscle relaxation when status is low. The 500 mg amount is clearly stated in a simple capsule.

Magnesium oxide has weak systemic absorption, so the high label amount may not provide strong stress-related support. It can also cause diarrhea or stomach cramping in sensitive users.

Study evidence
Magnesium Supportive 13 studies
Cardiovascular Support
Cardiovascular Support
Impact
Moderate effect
C Goal FitD- Strength of SupportD CoverageA- Formula Quality
Magnesium · 500 mg

Magnesium is relevant to vascular tone and heart rhythm, but the oxide form is poorly absorbed. The large labeled amount therefore overstates likely systemic contribution compared with citrate or bisglycinate.

A single mineral provides narrow support without lipid, nitric-oxide, or cellular-energy coverage. Magnesium oxide commonly causes diarrhea, which becomes more likely at a large amount.

Study evidence
Magnesium Supportive 123 studies
Heart Health
Heart Health
Impact
Moderate effect
C Goal FitD- Strength of SupportD CoverageA- Formula Quality
Magnesium · 500 mg

Magnesium is relevant to vascular tone and heart rhythm, but the oxide form is poorly absorbed. The large labeled amount therefore overstates likely systemic contribution compared with citrate or bisglycinate.

A single mineral provides narrow support without lipid, nitric-oxide, or cellular-energy coverage. Magnesium oxide commonly causes diarrhea, which becomes more likely at a large amount.

Study evidence
Magnesium Supportive 158 studies

Ingredients

IngredientAmount per serving
Magnesium
500 mg
Adults 18–50
Report overview
Magnesium · 500 mg OverallScore44
F Active Ingredient Quality & BioavailabilityB Dose, Safety & Label TransparencyD- Value

Magnesium oxide is inexpensive but has poor systemic absorption. The clearly stated serving is unusually high and may cause loose stools or abdominal discomfort. Low cost improves affordability, yet the source remains a weak choice when absorption is the priority.

View ingredientView products
Loading alternative details
91 Performance

Krebs Magnesium Potassium Complex

Nature's Way
Magnesium lysinate and malate provide favorable forms at a useful amount, with a modest potassium contribution. The better-absorbed form is more suitable for systemic magnesium replenishment than the original’s weaker form. The formula remains focused rather than comprehensive.
88 Performance

Magnesium Bisglycinate Powder

NOW
Magnesium bisglycinate supplies a well-absorbed form at a practical amount in an adjustable powder. The better-absorbed form is more suitable for systemic magnesium replenishment than the original’s weaker form. The single-mineral design does not address needs beyond magnesium.
85 Performance

Magnesium Bisglycinate 200 mg

Natural Factors
Magnesium bisglycinate provides a highly absorbable form at a moderate amount suited to routine use. The better-absorbed form is more suitable for systemic magnesium replenishment than the original’s weaker form. The focused formula offers no additional electrolyte or relaxation ingredients.
83 Budget

Magnesium Citrate Pure Powder

Best Naturals
Magnesium citrate in an adjustable powder provides useful absorption with a clearly stated amount. Its lower serving cost improves affordability, while citrate may loosen stools in sensitive users.
80 Budget

Magnesium Caps 500 mg

Life Extension
Citrate, succinate, and named glycinate broaden the magnesium forms in a very economical capsule. Its lower serving cost improves affordability, while the oxide portion lowers average absorption, and the large amount may cause diarrhea or cramping.
84 Budget

Potassium + Magnesium

Nutricost
Magnesium citrate with a modest potassium addition creates a simple two-mineral electrolyte formula. Its lower serving cost improves affordability, while potassium is only a supporting amount, and citrate may loosen stools in sensitive users.
80 Value

Magnesium Bisglycinate Chelate

Healthy Origins
TRAACS magnesium bisglycinate combines premium form quality, a useful elemental amount, and a clean powder format. The serving costs more, so the value advantage depends on prioritizing form quality. The formula is narrow, and supplied customer satisfaction is less convincing than its ingredient quality.
83 Value

Magnesium Citrate 420 mg

Nutricost
A substantial magnesium citrate amount offers useful absorption in a focused, economical formula. The comparable serving cost supports value without a cost penalty. The higher amount may loosen stools or cause abdominal discomfort in sensitive users.
82 Value

Magnesium Citrate 200 mg

The Vitamin Shoppe
A moderate magnesium citrate amount provides practical daily supplementation in a simple tablet. The lower serving cost strengthens quality-adjusted value. Tablet excipients and complete directions are not supplied, and citrate may affect digestive tolerance.
Report alternatives

Sources

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

  1. 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
  2. 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
  3. Effect of the laxative magnesium oxide on gastrointestinal functional recovery in fast-track colonic resection: a double-blind, placebo-controlled randomized study.
    Andersen J; Christensen H; Pachler JH; Hallin M; Thaysen HV; Kehlet H · Colorectal disease : the official journal of the Association of Coloproctology of Great Britain and Ireland · 2012
    Randomized trial49 participantsDigestive Health forMagnesium
  4. Diagnosis of magnesium-induced diarrhea.
    Fine KD; Santa Ana CA; Fordtran JS · The New England journal of medicine · 1991
    Clinical trial19 participantsDigestive Health forMagnesium
  5. Lactobacillus casei rhamnosus Lcr35 in children with chronic constipation.
    Bu LN; Chang MH; Ni YH; Chen HL; Cheng CC · Pediatrics international : official journal of the Japan Pediatric Society · 2007
    Randomized trial45 participantsDigestive Health forMagnesium
  6. 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
  7. 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
  8. 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
  9. 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
  10. 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
  11. 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
  12. 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
  13. 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
  14. 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
  15. 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
  16. 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
  17. 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
  18. 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
  19. 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
  20. 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
  21. 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
  22. Red blood cell magnesium and chronic fatigue syndrome.
    Cox IM; Campbell MJ; Dowson D · Lancet (London, England) · 1991
    Randomized trial32 participantsEnergy forMagnesium
  23. Exercise, magnesium and immune function.
    Laires MJ; Monteiro C · Magnesium research · 2008
    Narrative reviewEnergy forMagnesium
  24. 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
  25. 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
  26. 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
  27. 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
  28. 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
  29. 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
  30. 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
  31. 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
  32. 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
  33. 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
  34. 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
  35. 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
  36. 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
  37. 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
  38. 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
  39. 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
  40. 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