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Buffered C with Bioflavonoids

Swanson Premium Brand
4.9
★ ★ ★ ★ ★
(1166 ratings)
Vitamin C 500 mg
Flavonoid (mixture) 200 mg
Product Image
Score80
A balanced buffered formula for people who want meaningful vitamin C without a full-gram serving. The bioflavonoid total is useful, although its composition is not detailed.
How scoring works
Quantity:100 Capsule(s) • (100 servings)
Goals:
Immunity
Skin Health
General Health
Vision Support
Anti-Inflammatory Support

Score 80

A balanced buffered formula for people who want meaningful vitamin C without a full-gram serving. The bioflavonoid total is useful, although its composition is not detailed.
How scoring works
$13.19($0.13 per serving)
iHerb
$ 13.19
iHerb
$ 13.19
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Analysis

The 500 mg calcium ascorbate serving is substantial without pushing into a full-gram dose. Its buffered form may offer better digestive comfort while supporting normal immune function and collagen formation.

A 200 mg citrus bioflavonoid complex gives the formula meaningful complementary plant compounds. The total is clear, but the label does not identify how much of each flavonoid is supplied.

The single-capsule serving and simple ingredient structure make daily use straightforward. It offers less sheer vitamin C than many products in this group but may be a more measured choice for routine supplementation.

Who is it for
  • Adults preferring a moderate vitamin C amount
  • People with sensitivity to acidic supplements
  • Users wanting a one-capsule serving
Best for
  • Routine immune support
  • Collagen support
  • Moderate-dose antioxidant use

Pros

  • Buffered 500 mg vitamin C
  • Meaningful 200 mg bioflavonoid complex
  • One-capsule serving
  • Clearly listed main active amounts

Cons

  • Lower vitamin C amount than full-gram alternatives
  • Bioflavonoid makeup is not specified
  • No supporting nutrients beyond calcium and flavonoids

Warnings

  • Even 500 mg of vitamin C can cause stomach upset in sensitive users
  • Vitamin C can increase iron absorption, which matters for people with iron-overload disorders
  • Calcium ascorbate adds 60 mg of calcium per capsule

Nutrient quality

94 Highest impact

Calcium ascorbate supplies a well-regarded buffered form at a meaningful amount. The focused formula avoids low-value additions and fits the intended use closely.

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Ingredient transparency

84 Highest impact

Active names and amounts are clearly stated, with no hidden proprietary dose. Complete intake directions and a full inactive-ingredient list are not included in the supplied data.

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Customer satisfaction

73 High impact

Supplied satisfaction metrics indicate a strong result with a meaningful response pool. Detailed experience themes are absent, so recurring complaints and real-world purpose fit remain uncertain.

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Value for money

65 High impact

Serving value appears moderate relative to the disclosed form and amount. The focused formula avoids low-value extras.

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Report analysis

Goals

Immunity
Immunity
Impact
Highest effect
A+ Goal FitA+ Strength of SupportB CoverageA+ Formula Quality
Vitamin C · 500 mg

Buffered vitamin C at a meaningful amount gives direct antioxidant and immune support. Calcium ascorbate may be gentler on sensitive stomachs than plain ascorbic acid.

Citrus bioflavonoids add a related antioxidant pathway without diluting the main nutrient. The formula remains focused and clearly disclosed, though it does not cover vitamin D, zinc, or other immune mechanisms.

Study evidence
Vitamin C Supportive 53 studies
Skin Health
Skin Health
Impact
Highest effect
B+ Goal FitA Strength of SupportC+ CoverageA Formula Quality
Vitamin C · 500 mg

Vitamin C directly supports collagen synthesis and antioxidant protection in skin. The 500 mg amount gives this focused pathway meaningful depth.

Calcium ascorbate provides a buffered form with clear elemental calcium disclosure. The formula does not add hydration lipids, collagen peptides, or a separate photoprotection pathway.

Study evidence
Vitamin C Supportive 53 studies
General Health
General Health
Impact
Highest effect
A- Goal FitA Strength of SupportC CoverageA Formula Quality
Vitamin C · 500 mg

The buffered vitamin C dose provides focused support for antioxidant protection, normal immune function, and collagen production. Calcium ascorbate is clearly identified and may be easier on the stomach than ordinary ascorbic acid.

The formula has good depth for vitamin C, with a separately disclosed calcium contribution and a meaningful bioflavonoid amount. Its narrow design does not cover wider general-health needs such as vitamin D, magnesium, essential fatty acids, or broader micronutrient gaps.

Study evidence
Vitamin C Supportive 56 studies
Vision Support
Vision Support
Impact
High effect
C+ Goal FitA Strength of SupportD CoverageB Formula Quality
Vitamin C · 500 mg

Vitamin C supports antioxidant defense in the lens and retina, and the 500 mg serving provides an ample amount. The buffered form may be easier on the stomach, while citrus bioflavonoids add secondary antioxidant support.

Vision evidence for vitamin C is strongest as part of a balanced antioxidant combination rather than by itself. The formula lacks lutein, zeaxanthin, vitamin E, zinc at an AREDS-style amount, and omega-3 fats.

Study evidence
Vitamin C Disputed 24 studies
Anti-Inflammatory Support
Anti-Inflammatory Support
Impact
High effect
D+ Goal FitA- Strength of SupportC- CoverageA Formula Quality
Vitamin C · 500 mg

Vitamin C provides antioxidant support and may help regulate inflammatory stress, but it is not a targeted inflammation-modulating active. Bioflavonoids broaden antioxidant coverage without adding a strong direct pathway.

Buffered calcium ascorbate may be gentler on the stomach and is clearly disclosed. The focused formula is better suited to basic antioxidant nutrition than pronounced inflammatory support.

Study evidence
Vitamin C Supportive 50 studies

Ingredients

IngredientAmount per serving
Vitamin C (Calcium Ascorbate)
 500 mg
Calcium (Calcium Ascorbate)
 60 mg
Citrus Bioflavonoid Complex
200 mg
Adults 18–50
Report overview
Vitamin C (Calcium Ascorbate) · 500 mg OverallScore79
B+ Active Ingredient Quality & BioavailabilityA Dose, Safety & Label TransparencyD+ Value
Calcium ascorbate provides a buffered vitamin C form that should suit users who find plain ascorbic acid harsh. The 500 mg dose is well targeted, and the label separately identifies calcium from the buffered source. Cost efficiency is average rather than a leading strength.
View ingredientView products
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89 Performance

C-500 Calcium Ascorbate-C

NOW
<p>The ingredient profile makes it a stronger quality-focused alternative for the same vitamin C goals. Buffered calcium ascorbate delivers a practical vitamin C amount with clear mineral disclosure and exceptional relative value. The small bioflavonoid addition is unlikely to contribute much but does not undermine the strong core formula.</p>
86 Performance

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<p>The ingredient profile makes it a stronger quality-focused alternative for the same vitamin C goals. Fully buffered calcium ascorbate provides a meaningful vitamin C serving with good stomach-comfort potential. The focused formula keeps the active nutrient clear and avoids decorative additions.</p>
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Ester-C with Citrus Bioflavonoids

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<p>The ingredient profile makes it a stronger quality-focused alternative for the same vitamin C goals. A buffered vitamin C form and a substantial citrus bioflavonoid amount create a simple, well-dosed antioxidant formula. Strong satisfaction signals and a long supply support value, though excipients and intake directions are not shown.</p>
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Pure Buffered Calcium Ascorbate

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<p>The lower serving cost makes it a more economical alternative while retaining the same vitamin C focus. the buffered mineral ascorbate form supplies a meaningful vitamin C amount with a digestive-comfort advantage over plain ascorbic acid. Clear active dosing and favorable serving value are strengths, though complete use directions and inactive ingredients are not supplied.</p>
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100% Pure Vitamin C Powder

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<p>The lower serving cost makes it a more economical alternative while retaining the same vitamin C focus. The pure powder supplies a flexible, meaningful vitamin C serving with exceptional economy and no active padding. Plain ascorbic acid remains acidic, so sensitive users may prefer a buffered form.</p>
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C 500 mg

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<p>The lower serving cost makes it a more economical alternative while retaining the same vitamin C focus. A simple moderate-dose tablet provides useful vitamin C at excellent relative value and with extensive aggregate feedback. Generic ascorbic acid and missing inactive-ingredient details are the main limitations.</p>
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Pure Buffered Magnesium Ascorbate

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<p>The formula offers a more favorable balance of vitamin C quality and serving value than the original. Magnesium ascorbate provides a substantial fully buffered vitamin C serving with excellent relative value and clear mineral disclosure. Feedback volume is limited, and detailed use directions or non-active ingredients are not supplied.</p>
83 Value

C 500 mg

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<p>The formula offers a more favorable balance of vitamin C quality and serving value than the original. A large supply of straightforward vitamin C provides meaningful daily support with excellent value. Basic ascorbic acid and incomplete inactive-ingredient details keep the formula from feeling premium.</p>
84 Value

Ester-C 500 mg With Citrus Bioflavoinds

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<p>The formula offers a more favorable balance of vitamin C quality and serving value than the original. Buffered Ester-C provides a substantial vitamin C serving with good stomach-comfort potential. Citrus bioflavonoids add compatible plant compounds without distracting from the core nutrient.</p>
Report alternatives

Sources

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

  1. Vitamin C and contribution to the normal function of the immune system: evaluation of a health claim pursuant to Article 14 of Regulation (EC) No 1924/2006.
    EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA) · EFSA journal. European Food Safety Authority · 2026
    Guideline / consensusImmunity forVitamin C
  2. Effect of Vitamin C Supplements on Respiratory Tract Infections: A Systematic Review and Meta-Analysis.
    Keya TA; Leela A; Fernandez K; Habib N; Rashid M · Current reviews in clinical and experimental pharmacology · 2022
    Meta-analysis10 studies pooledImmunity forVitamin C
  3. Vitamin C supplementation and salivary immune function following exercise-heat stress.
    Carrillo AE; Murphy RJ; Cheung SS · International journal of sports physiology and performance · 2009
    Randomized trial12 participantsImmunity forVitamin C
  4. Enhanced Vitamin C Delivery: A Systematic Literature Review Assessing the Efficacy and Safety of Alternative Supplement Forms in Healthy Adults.
    Calder PC; Kreider RB; McKay DL · Nutrients · 2025
    Systematic review13 studies pooledImmunity forVitamin C
  5. Dietary nutrient intakes and skin-aging appearance among middle-aged American women.
    Cosgrove MC; Franco OH; Granger SP; Murray PG; Mayes AE · The American journal of clinical nutrition · 2007
    Cross-sectional study4,025 participantsSkin Health forVitamin C
  6. Double-blind, half-face study comparing topical vitamin C and vehicle for rejuvenation of photodamage.
    Fitzpatrick RE; Rostan EF · Dermatologic surgery : official publication for American Society for Dermatologic Surgery [et al.] · 2002
    Non-randomized trial10 participantsSkin Health forVitamin C
  7. Vitamin C and postoperative outcomes following mandibular third molar extraction: a randomized split-mouth study.
    Demirel M; Aktas A; Kizil M; Yalcin N · Oral surgery, oral medicine, oral pathology and oral radiology · 2026
    Randomized trial56 participantsSkin Health forVitamin C
  8. Efficacy of Vitamin C as Glucocorticoid Substitute for Reducing Pain and Inflammation After Total Hip Arthroplasty: A Randomized Controlled Trial.
    Jiang W; Xu H; Jiang X; Zhan Y; Ju Y; Xie J; Huang Z; Huang Q; Pei F · The Journal of bone and joint surgery. American volume · 2025
    Randomized trial107 participantsAnti-Inflammatory Support forVitamin C
  9. The Impact of Vitamin C on Analgesic, Anti-inflammatory, and Hemostatic Outcomes After Total Hip and Knee Arthroplasty: A Systematic Review and Meta-Analysis.
    Moftakhari Hajimirzaei S; Bagherzadeh Cham M; Dolikhani M; Tabatabaee SM; Ebrahimpour A · The archives of bone and joint surgery · 2026
    Meta-analysis1,162 participants10 studies pooledAnti-Inflammatory Support forVitamin C
  10. The impact of vitamin C supplementation on the perioperative outcomes after total hip and knee arthroplasty: a systematic review and meta-analysis.
    Liu X; Guo J; Li Y; Yang Y; Liu M; Gao Q; Yang Y; Wu X; Yue C · BMC musculoskeletal disorders · 2026
    Meta-analysis852 participants8 studies pooledAnti-Inflammatory Support forVitamin C
  11. Therapeutic Impact of Ascorbic Acid on Oral and Periodontal Tissues: A Systematic Literature Review.
    Ruzijevaite G; Acaite E; Jagelaviciene E · Medicina (Kaunas, Lithuania) · 2025
    Systematic review811 participants17 studies pooledAnti-Inflammatory Support forVitamin C
  12. Oral vitamin C administration reduces early recurrence rates after electrical cardioversion of persistent atrial fibrillation and attenuates associated inflammation.
    Korantzopoulos P; Kolettis TM; Kountouris E; Dimitroula V; Karanikis P; Pappa E; Siogas K; Goudevenos JA · International journal of cardiology · 2005
    Randomized trial44 participantsAnti-Inflammatory Support forVitamin C
  13. Dietary intake and blood concentrations of antioxidants and the risk of cardiovascular disease, total cancer, and all-cause mortality: a systematic review and dose-response meta-analysis of prospective studies.
    Aune D; Keum N; Giovannucci E; Fadnes LT; Boffetta P; Greenwood DC; Tonstad S; Vatten LJ; Riboli E; Norat T · The American journal of clinical nutrition · 2019
    Meta-analysis69 studies pooledGeneral Health forVitamin C
  14. Scientific Opinion on the substantiation of a health claim related to vitamin C and increasing non haem iron absorption pursuant to Article 14 of Regulation (EC) No 1924/2006.
    EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA) · EFSA journal. European Food Safety Authority · 2026
    Guideline / consensusGeneral Health forVitamin C
  15. Vitamin C Depletion and All-Cause Mortality in Renal Transplant Recipients.
    Sotomayor CG; Eisenga MF; Gomes Neto AW; Ozyilmaz A; Gans ROB; Jong WHA; Zelle DM; Berger SP; Gaillard CAJM; Navis GJ; Bakker SJ · Nutrients · 2018
    Cohort study598 participantsGeneral Health forVitamin C
  16. Associations of Serum Biomarkers of Fruit and Vegetable Intake With the Risk of Cause-Specific Mortality and All-Cause Mortality: A National Prospective Cohort Study.
    Pu L; Zhang R; Wang X; Zhao T; Sun H; Han L · Frontiers in nutrition · 2022
    Cohort study12,530 participantsGeneral Health forVitamin C
  17. Relation between plasma ascorbic acid and mortality in men and women in EPIC-Norfolk prospective study: a prospective population study. European Prospective Investigation into Cancer and Nutrition.
    Khaw KT; Bingham S; Welch A; Luben R; Wareham N; Oakes S; Day N · Lancet (London, England) · 2001
    Cohort study19,496 participantsGeneral Health forVitamin C
  18. Therapeutic effects of high-dose vitamin C supplementation in patients with COVID-19: a meta-analysis.
    Sun L; Zhao JH; Fan WY; Feng B; Liu WW; Chen RQ; Ban C; Dang AG; Wang M; Luo KT; Zhou GY; Yu FF; Ba Y · Nutrition reviews · 2024
    Meta-analysis2,334 participants14 studies pooledImmunity forVitamin C
  19. Effect of micronutrient supplements on influenza and other respiratory tract infections among adults: a systematic review and meta-analysis.
    Abioye AI; Bromage S; Fawzi W · BMJ global health · 2021
    Meta-analysisImmunity forVitamin C
  20. New evidence for antioxidant properties of vitamin C.
    Vojdani A; Bazargan M; Vojdani E; Wright J · Cancer detection and prevention · 2001
    Randomized trial20 participantsImmunity forVitamin C
  21. Evaluation of the anti-wrinkle effect of an ascorbic acid-loaded dissolving microneedle patch via a double-blind, placebo-controlled clinical study.
    Lee C; Yang H; Kim S; Kim M; Kang H; Kim N; An S; Koh J; Jung H · International journal of cosmetic science · 2017
    Randomized trial23 participantsSkin Health forVitamin C
  22. Comparative Study on the Outcome of Periorbital Wrinkles Treated with Laser-Assisted Delivery of Vitamin C or Vitamin C Plus Growth Factors: A Randomized, Double-blind, Clinical Trial.
    Machado BHB; Frame J; Zhang J; Najlah M · Aesthetic plastic surgery · 2021
    Randomized trial149 participantsSkin Health forVitamin C
  23. Randomized trial of topical ascorbic acid in DMSO versus imiquimod for the treatment of basal cell carcinoma.
    Burke B; Bailie JE · Biomedicine & pharmacotherapy = Biomedecine & pharmacotherapie · 2022
    Randomized trial25 participantsSkin Health forVitamin C
  24. Vitamin C improves healing of foot ulcers: a randomised, double-blind, placebo-controlled trial.
    Gunton JE; Girgis CM; Lau T; Vicaretti M; Begg L; Flood V · The British journal of nutrition · 2022
    Randomized trial16 participantsSkin Health forVitamin C
  25. Role of Oral Vitamin 'C' on Astigmatic Errors in Phacoemulsification.
    Mohan S; Sah K; Khattri M; Ahmad L; Sachan SK · Current eye research · 2021
    Randomized trial400 participantsVision Support forVitamin C
  26. Ascorbic acid metabolites are involved in intraocular pressure control in the general population.
    Hysi PG; Khawaja AP; Menni C; Tamraz B; Wareham N; Khaw KT; Foster PJ; Benet LZ; Spector TD; Hammond CJ · Redox biology · 2019
    Observational studyVision Support forVitamin C
  27. Nutritional modulation of cataract.
    Weikel KA; Garber C; Baburins A; Taylor A · Nutrition reviews · 2014
    Narrative reviewVision Support forVitamin C
  28. Dietary n-3 Fatty Acid, α-Tocopherol, Zinc, vitamin D, vitamin C, and β-carotene are Associated with Age-Related Macular Degeneration in Japan.
    Aoki A; Inoue M; Nguyen E; Obata R; Kadonosono K; Shinkai S; Hashimoto H; Sasaki S; Yanagi Y · Scientific reports · 2017
    Case-control study530 participantsVision Support forVitamin C
  29. Adherence to a Mediterranean diet, lifestyle and age-related macular degeneration: the Coimbra Eye Study - report 3.
    Raimundo M; Mira F; Cachulo MDL; Barreto P; Ribeiro L; Farinha C; Laíns I; Nunes S; Alves D; Figueira J; Merle BM; Delcourt C; Santos L; Silva R · Acta ophthalmologica · 2019
    Case-control study883 participantsVision Support forVitamin C