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Genuine Phillips' Caplets

4.6
★ ★ ★ ★ ★
(6626 ratings)
Magnesium 500 mg
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Score68
A simple, substantial magnesium serving is the main benefit. Unknown form quality and a 500 mg dose create meaningful uncertainty about absorption and digestive comfort.
How scoring works
Tablet
Quantity:100 Tablet(s) • (50 servings)
Goals:
Digestive Health
Stress Relief
Energy

Score 68

A simple, substantial magnesium serving is the main benefit. Unknown form quality and a 500 mg dose create meaningful uncertainty about absorption and digestive comfort.
How scoring works
$16.16($0.32 per serving)
Vitacost
$ 19.09
iHerb
$ 17.34
Amazon
$ 16.16
iHerb
$ 17.34
Report prices

Analysis

The two-tablet serving provides 500 mg of magnesium with no unrelated active ingredients. That amount is substantial enough to address a defined magnesium gap but is more than many users need from a routine supplement.

The chemical form is not disclosed in the supplied data, so expected absorption and digestive effects cannot be compared with citrate, glycinate, or oxide products. The broad heart, energy, bone, stress, and digestive goals all depend mainly on whether magnesium intake is actually low.

A 50-serving bottle and moderate cost are practical. Dose flexibility is limited by the high full serving, and sensitive users may need less than the label amount.

Who is it for
  • Adults with a defined magnesium intake gap
  • Users seeking a simple single-mineral formula
  • People able to tolerate or adjust a high serving
Best for
  • Focused magnesium support
  • A straightforward two-tablet formula
  • Users who do not need added actives

Pros

  • Provides 500 mg of magnesium
  • Uses a focused single-active design
  • Offers 50 listed servings
  • Has reasonable serving value

Cons

  • Does not disclose the magnesium form
  • The full serving is aggressive
  • Inactive ingredients are not shown
  • Broad goal claims exceed the narrow formula

Warnings

  • The 500 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

69 High impact

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

.

Ingredient transparency

67 High impact

The elemental amount is clearly stated without a hidden key dose. Complete directions and inactive ingredients are not supplied.

.

Customer satisfaction

70 High impact

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

.

Value for money

65 High impact

Serving economics are reasonable for the supplied amount. Weak form disclosure or high cost limits category value.

.
Report analysis

Goals

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

A 500 mg magnesium serving can draw water into the bowel and support short-term stool passage. The formula targets one narrow regularity mechanism rather than broader digestive health.

The amount is high enough to cause diarrhea, cramping, or electrolyte disturbance if overused. The supplied data do not identify the magnesium compound, so solubility and likely potency cannot be judged fully.

Study evidence
Magnesium Supportive 50 studies
Stress Relief
Stress Relief
Impact
High effect
B Goal FitD+ Strength of SupportD+ CoverageA Formula Quality
Magnesium · 500 mg

The clearly stated magnesium amount could support nervous-system regulation when intake is low. The missing chemical form prevents any reliable judgment of absorption or stomach tolerance.

The serving is also above the usual supplemental range and may cause diarrhea or cramping. Its single-mineral focus offers depth only if the undisclosed form is usable and well tolerated.

Study evidence
Magnesium Supportive 13 studies
Energy
Energy
Impact
High effect
A- Goal FitD+ Strength of SupportD- CoverageB+ Formula Quality
Magnesium · 500 mg

Magnesium supports cellular energy, muscle function, and normal nerve signaling. The elemental amount is clear, but the chemical form is not disclosed.

A 500 mg serving is above a typical routine range and may increase gastrointestinal effects. Missing form information makes absorption quality impossible to judge reliably.

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

Magnesium supports many normal metabolic, muscle, and nervous-system functions, giving the product a sound general-health basis. The single-ingredient approach is focused and avoids distracting blends.

The undisclosed magnesium form makes absorption and tolerance difficult to judge. A 500 mg serving may cause diarrhea or abdominal discomfort, especially when used routinely without adjusting the dose.

Study evidence
Magnesium Supportive 114 studies
Testosterone Support
Testosterone Support
Impact
Moderate effect
B- Goal FitD Strength of SupportD CoverageA Formula Quality
Magnesium · 500 mg

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

The formula remains narrow rather than comprehensive. The large magnesium amount may cause diarrhea, cramping, and fluid loss, especially because an oxide form is present.

Study evidence
Magnesium Disputed 5 studies
Cardiovascular Support
Cardiovascular Support
Impact
Moderate effect
C+ Goal FitC Strength of SupportD- CoverageB Formula Quality
Magnesium · 500 mg

Magnesium has a clear cardiovascular role in vascular tone and normal rhythm, and the amount is substantial. The missing chemical form prevents a reliable judgment of absorption and suitability for regular supplementation.

A single mineral gives useful depth but no coverage of lipids, cellular energy, or homocysteine. The high supplemental amount may cause diarrhea or abdominal cramping, particularly if the form is poorly absorbed.

Study evidence
Magnesium Supportive 123 studies

Ingredients

IngredientAmount per serving
Magnesium
500 mg
Adults 18–50 Children 4+
Report overview
Magnesium · 500 mg OverallScore39
F Active Ingredient Quality & BioavailabilityB Dose, Safety & Label TransparencyD- Value

The undisclosed magnesium form prevents a reliable assessment of absorption quality. The elemental amount is clearly disclosed but sits above the standard 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 500 mg magnesium amount with an unspecified form, 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 500 mg magnesium amount with an unspecified form, 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 500 mg magnesium amount with an unspecified form, 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 500 mg magnesium amount with an unspecified form, 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 500 mg magnesium amount with an unspecified form.</p>
84 Budget

Potassium + Magnesium

Nutricost
<p>The lower-cost two-mineral formula 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 500 mg magnesium amount with an unspecified form.</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 500 mg magnesium amount with an unspecified form, 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 500 mg magnesium amount with an unspecified form, 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 500 mg magnesium amount with an unspecified form, 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. 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. Exercise, magnesium and immune function.
    Laires MJ; Monteiro C · Magnesium research · 2008
    Narrative reviewEnergy forMagnesium
  3. 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
  4. Effects of zinc and magnesium supplements on postpartum depression and anxiety: A randomized controlled clinical trial.
    Fard FE; Mirghafourvand M; Mohammad-Alizadeh Charandabi S; Farshbaf-Khalili A; Javadzadeh Y; Asgharian H · Women & health · 2017
    Randomized trial99 participantsStress Relief forMagnesium
  5. 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 pooledHeart Health Cardiovascular Support forMagnesium
  6. 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 participantsHeart Health forMagnesium
  7. 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
  8. 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
  9. 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
  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. 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
  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. 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
  23. 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
  24. Red blood cell magnesium and chronic fatigue syndrome.
    Cox IM; Campbell MJ; Dowson D · Lancet (London, England) · 1991
    Randomized trial32 participantsEnergy forMagnesium
  25. 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
  26. 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
  27. 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
  28. 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
  29. 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
  30. 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
  31. 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
  32. 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
  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