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Calcium 500+D3

4.8
★ ★ ★ ★ ★
(10644 ratings)
Calcium 500 mg
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Score80
Calcium and vitamin D3 come in a practical serving size. Unspecified calcium chemistry behind the oyster source limits confidence in absorption.
How scoring works
Quantity:90 Tablet(s) • (90 servings)
Goals:
Bone Health

Score 80

Calcium and vitamin D3 come in a practical serving size. Unspecified calcium chemistry behind the oyster source limits confidence in absorption.
How scoring works

Also available as

3 options
400 servings Calcium 500 mg • 400 Tablet(s) • 400 servings $6.72 ($0.01 per serving) 15.00mcg Vitamin D3 • 400 servings Calcium 500 mg • 400 Tablet(s) • 400 servings $10.99 ($0.02 per serving) 15.00mcg Vitamin D3 • 90 Tablet(s) servings Calcium 500 mg • 90 Tablet(s) • 90 servings $5.49 ($0.06 per serving)
$5.49($0.06 per serving)
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Analysis

The calcium amount fits well within a single serving, and vitamin D3 adds useful complementary support. Together they address mineral supply and calcium use without an oversized dose.

Labeling the source as oyster does not reveal whether the calcium is carbonate or another compound. That gap makes bioavailability harder to judge, so taking it with food is a cautious approach.

The simple tablet may suit people who value convenience and already cover other bone nutrients elsewhere. Users who want precise form disclosure may prefer a clearly labeled citrate or chelated product.

Who is it for
  • Adults seeking calcium with modest vitamin D3
  • Users comfortable with an oyster-derived ingredient
  • People wanting a simple one-tablet routine
Best for
  • Basic bone-support supplementation
  • Moderate calcium intake
  • Meal-based daily use

Pros

  • Calcium amount is well sized for one serving
  • Vitamin D3 complements calcium
  • Focused formula is easy to use

Cons

  • Exact calcium compound is not disclosed
  • Vitamin D3 amount is modest
  • No vitamin K or magnesium

Warnings

  • Calcium can reduce levothyroxine absorption, so follow the medication instructions for spacing the doses.
  • Separate calcium from tetracycline or quinolone antibiotics by the interval stated by the prescriber or pharmacist.
  • Supplemental calcium can cause constipation or bloating; dividing intake may improve tolerance when the label permits it.
  • Calcium carbonate generally works best with food and may be less dependable when stomach acid is low or acid-suppressing medicine is used.
  • The calcium is oyster-derived, which may not suit people avoiding shell-derived ingredients.

Nutrient quality

83 Highest impact

The calcium amount is well sized, and vitamin D3 supports its use. The unspecified oyster-derived calcium form and modest vitamin D3 amount limit formulation confidence.

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Ingredient transparency

75 High impact

Active amounts and serving counts are mostly clear from the supplied label facts. Missing non-active ingredients and complete directions leave practical disclosure gaps.

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Customer satisfaction

73 High impact

The aggregate rating is strong and supported by an extensive feedback volume. Specific experience details are missing, so recurring problems and purpose fit remain uncertain.

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Value for money

90 Highest impact

The accessible cost supports value despite uncertainty about the calcium form. Serving value is strong for a calcium and vitamin D formula.

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Goals

Bone Health
Bone Health
Impact
High effect
A- Goal FitB- Strength of SupportC- CoverageA- Formula Quality
Calcium · 500 mgVitamin D · 5 mcg

Calcium and vitamin D3 provide focused support for skeletal mineralization. The calcium amount is well suited to a single dose.

The oyster source does not identify the exact calcium compound, which limits confidence in absorption. The vitamin D3 amount is modest, and the formula does not address mineral transport or bone-matrix support.

Study evidence
Calcium Supportive 144 studies
Vitamin D Supportive 202 studies

Ingredients

IngredientAmount per serving
Vitamin D3 (Cholecalciferol)
 5 mcg
Calcium (Oyster)
 500 mg
Gluten Free Adults 18–50
Report overview
Calcium (Oyster) · 500 mg OverallScore72
F Active Ingredient Quality & BioavailabilityA+ Dose, Safety & Label TransparencyA+ Value

The 500 mg calcium serving is efficiently sized, but an oyster source does not reveal the exact calcium compound. That missing chemical form makes absorption potential difficult to judge even though the elemental amount is clear. Vitamin D3, a low serving cost, and no listed concerning additives support practical use.

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Loading alternative details
88 Performance

Calcium Hydroxyapatite Caps

NOW
<p>Hydroxyapatite supplies a practical calcium amount with naturally paired phosphorus in a simple capsule. Compared with Calcium 500+D3, its calcium form and supporting nutrients may be a better fit where the oyster source does not reveal the calcium compound, so absorption quality remains uncertain, while clear dosing, strong form quality, and favorable serving value make the formula well suited to routine bone support.</p>
85 Performance

Cal/Mag 500 mg/250 mg

NaturesPlus
<p>Chelated calcium and magnesium provide a focused, balanced mineral formula with strong form quality. Compared with Calcium 500+D3, its calcium form and supporting nutrients may be a better fit where the oyster source does not reveal the calcium compound, so absorption quality remains uncertain, while a simple one-serving format and economical cost make it one of the better value profiles in this set.</p>
83 Performance

600 + D3 plus Minerals

21st Century
<p>Calcium carbonate and vitamin D3 provide a direct, economical base for bone maintenance. Compared with Calcium 500+D3, its calcium form and supporting nutrients may be a better fit where the oyster source does not reveal the calcium compound, so absorption quality remains uncertain, while supportive minerals broaden the formula, though oxide forms and small secondary doses keep ingredient quality basic.</p>
85 Budget

600+D3

21st Century
<p>Calcium carbonate and vitamin D3 provide a focused bone-support pairing at exceptionally accessible value. Its lower recurring cost than Calcium 500+D3 makes it a more economical calcium option, while the calcium amount is reasonably sized, though carbonate works best with food and offers less flexibility than citrate. Calcium should be separated from levothyroxine and tetracycline or quinolone antibiotics because it can reduce their absorption.</p>
85 Budget

Calcium Carbonate

NOW
<p>The pure powder supplies a substantial calcium amount with excellent serving value and no unrelated actives. Its lower recurring cost than Calcium 500+D3 makes it a more economical calcium option, while calcium carbonate is less flexible than citrate because food and stomach acid aid absorption.</p>
84 Budget

Calcium 600 with Vitamin D3

Nature's Bounty
<p>Calcium and vitamin D3 form a focused, meaningfully dosed bone-support combination with strong serving value. Its lower recurring cost than Calcium 500+D3 makes it a more economical calcium option, while calcium carbonate is best taken with food, and the formula does not cover magnesium or vitamin K.</p>
85 Value

Cal/Mag Caps

NaturesPlus
<p>Soy amino acid chelates provide a focused calcium-magnesium formula with balanced doses and strong form quality. Compared with Calcium 500+D3, its calcium profile offers a practical quality-to-cost trade-off despite not costing less, while good ratings and economical servings support solid value, though the review base is smaller than leading products.</p>
88 Value

Calcium Citrate Pure Powder

NOW
<p>Calcium citrate supplies a substantial, well-absorbed dose in a simple powder with clear active disclosure. Compared with Calcium 500+D3, its calcium profile offers a practical quality-to-cost trade-off despite not costing less, while the focused formula offers strong value but does not provide vitamin D, vitamin K, or magnesium.</p>
82 Value

Calcium Citrate

Nature's Way
<p>Citrate and malate improve absorption quality within the mixed calcium formula. Compared with Calcium 500+D3, its calcium profile offers a practical quality-to-cost trade-off despite not costing less, while active doses are clear, while missing excipient and full use details limit transparency.</p>
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Sources

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

  1. Calcium supplementation during pregnancy and maternal and offspring bone health: a systematic review and meta-analysis.
    Tihtonen K; Korhonen P; Isojärvi J; Ojala R; Ashorn U; Ashorn P; Tammela O · Annals of the New York Academy of Sciences · 2022
    Meta-analysis1,566 participants7 studies pooledBone Health forCalcium
  2. Calcium supplementation and bone mineral density in postmenopausal women using estrogen replacement therapy.
    Haines CJ; Chung TK; Leung PC; Hsu SY; Leung DH · Bone · 1995
    Randomized trialBone Health forCalcium
  3. Bone turnover and the response to alendronate treatment in postmenopausal osteoporosis.
    Gonnelli S; Cepollaro C; Pondrelli C; Martini S; Montagnani A; Monaco R; Gennari C · Calcified tissue international · 1999
    Randomized trial100 participantsBone Health forCalcium
  4. Associations of dietary calcium intake with metabolic syndrome and bone mineral density among the Korean population: KNHANES 2008-2011.
    Kim MK; Chon SJ; Noe EB; Roh YH; Yun BH; Cho S; Choi YS; Lee BS; Seo SK · Osteoporosis international : a journal established as result of cooperation between the European Foundation for Osteoporosis and the National Osteoporosis Foundation of the USA · 2018
    Cross-sectional study14,705 participantsBone Health forCalcium
  5. Treatment with alendronate plus calcium, alendronate alone, or calcium alone for postmenopausal low bone mineral density.
    Bonnick S; Broy S; Kaiser F; Teutsch C; Rosenberg E; DeLucca P; Melton M · Current medical research and opinion · 2007
    Randomized trial701 participantsBone Health forCalcium
  6. Calcium and osteoporosis.
    Nordin BE · Nutrition (Burbank, Los Angeles County, Calif.) · 1998
    Meta-analysis20 studies pooledBone Health forCalcium
  7. Dietary calcium intake protects women consuming oral contraceptives from spine and hip bone loss.
    Teegarden D; Legowski P; Gunther CW; McCabe GP; Peacock M; Lyle RM · The Journal of clinical endocrinology and metabolism · 2005
    Randomized trial154 participantsBone Health forCalcium
  8. Relationship between bone mineral density changes and risk of fractures among patients receiving calcium with or without vitamin D supplementation: a meta-regression.
    Rabenda V; Bruyère O; Reginster JY · Osteoporosis international : a journal established as result of cooperation between the European Foundation for Osteoporosis and the National Osteoporosis Foundation of the USA · 2011
    Meta-analysis47,365 participants15 studies pooledBone Health forCalcium
  9. Calcium supplementation provides an extended window of opportunity for bone mass accretion after menarche.
    Rozen GS; Rennert G; Dodiuk-Gad RP; Rennert HS; Ish-Shalom N; Diab G; Raz B; Ish-Shalom S · The American journal of clinical nutrition · 2003
    Randomized trial100 participantsBone Health forCalcium
  10. Effect of milk and calcium supplementation on bone density and bone turnover in pregnant Chinese women: a randomized controlled trail.
    Liu Z; Qiu L; Chen YM; Su YX · Archives of gynecology and obstetrics · 2011
    Randomized trial36 participantsBone Health forCalcium
  11. What is the impact of daily oral supplementation of vitamin D3 (cholecalciferol) plus calcium on the incidence of hip fracture in older people? A systematic review and meta-analysis.
    Manoj P; Derwin R; George S · International journal of older people nursing · 2023
    Meta-analysis12,620 participants7 studies pooledBone Health forCalcium
  12. Calcium supplementation prevents seasonal bone loss and changes in biochemical markers of bone turnover in elderly New England women: a randomized placebo-controlled trial.
    Storm D; Eslin R; Porter ES; Musgrave K; Vereault D; Patton C; Kessenich C; Mohan S; Chen T; Holick MF; Rosen CJ · The Journal of clinical endocrinology and metabolism · 1998
    Randomized trial60 participantsBone Health forCalcium
  13. The effects of calcium supplementation (milk powder or tablets) and exercise on bone density in postmenopausal women.
    Prince R; Devine A; Dick I; Criddle A; Kerr D; Kent N; Price R; Randell A · Journal of bone and mineral research : the official journal of the American Society for Bone and Mineral Research · 1995
    Randomized trial168 participantsBone Health forCalcium
  14. The efficacy of calcium supplementation alone in elderly Thai women over a 2-year period: a randomized controlled trial.
    Rajatanavin R; Chailurkit L; Saetung S; Thakkinstian A; Nimitphong H · Osteoporosis international : a journal established as result of cooperation between the European Foundation for Osteoporosis and the National Osteoporosis Foundation of the USA · 2014
    Randomized trial404 participantsBone Health forCalcium
  15. Calcium-enriched foods and bone mass growth in prepubertal girls: a randomized, double-blind, placebo-controlled trial.
    Bonjour JP; Carrie AL; Ferrari S; Clavien H; Slosman D; Theintz G; Rizzoli R · The Journal of clinical investigation · 1997
    Randomized trial149 participantsBone Health forCalcium
  16. Pregnancy vitamin D supplementation and offspring bone mineral density in childhood follow-up of a randomized controlled trial.
    Moon RJ; D' Angelo S; Curtis EM; Ward KA; Crozier SR; Schoenmakers I; Javaid MK; Bishop NJ; Godfrey KM; Cooper C; Harvey NC; MAVIDOS Trial Group · The American journal of clinical nutrition · 2024
    Randomized trial454 participantsBone Health forVitamin D
  17. Vitamin D analogs and bone: preclinical and clinical studies with eldecalcitol.
    Matsumoto T; Takano T; Saito H; Takahashi F · BoneKEy reports · 2014
    Narrative reviewBone Health forVitamin D
  18. Efficacy of vitamin D fortified foods on bone mineral density and serum bone biomarkers: A systematic review and meta-analysis of interventional studies.
    Tangestani H; Djafarian K; Emamat H; Arabzadegan N; Shab-Bidar S · Critical reviews in food science and nutrition · 2020
    Meta-analysis1,786 participants20 studies pooledBone Health forVitamin D
  19. Cholecalciferol Supplementation Attenuates Bone Loss in Incident Kidney Transplant Recipients: A Prespecified Secondary Endpoint Analysis of a Randomized Controlled Trial.
    Tsujita M; Doi Y; Obi Y; Hamano T; Tomosugi T; Futamura K; Okada M; Hiramitsu T; Goto N; Isaka Y; Takeda A; Narumi S; Watarai Y · Journal of bone and mineral research : the official journal of the American Society for Bone and Mineral Research · 2022
    Randomized trial193 participantsBone Health forVitamin D
  20. Vitamin D supplementation and bone health in post-menopausal women: a 24-month randomized controlled intervention with enhanced bioavailability formulations.
    Rasool N; Munir Y · European journal of clinical nutrition · 2026
    Randomized trial612 participantsBone Health forVitamin D