Product Image

C

Swanson
4.6
★ ★ ★ ★ ★
(262 ratings)
Vitamin C 1000 mg
Flavonoid (mixture) 200 mg
Product Image
Score86
A clearly dosed, buffered full-gram vitamin C tablet with useful bioflavonoids and a long supply. It is focused and high-value, though the flavonoid composition remains broad.
How scoring works
Quantity:250 Tablet(s) • (250 servings)
Goals:
Immunity
General Health
Anti-Inflammatory Support
Skin Health
Vision Support

Score 86

A clearly dosed, buffered full-gram vitamin C tablet with useful bioflavonoids and a long supply. It is focused and high-value, though the flavonoid composition remains broad.
How scoring works
$25.39($0.10 per serving)
iHerb
$ 25.39
iHerb
$ 25.39
Report prices

Analysis

A full gram of vitamin C from calcium ascorbate provides a substantial dose in a buffered form. The separate calcium amount improves clarity and helps users account for the mineral contribution.

The 200 mg citrus bioflavonoid component complements vitamin C without crowding the formula. Its total amount is disclosed, although the specific flavonoids and their individual quantities are not.

The 250-serving bottle favors long-term use and reduces the need for frequent repurchasing. A large tablet may be less comfortable for people who prefer capsules, powders, or divided dosing.

Who is it for
  • Adults seeking long-term buffered vitamin C
  • Users who value clear active dosing
  • People comfortable swallowing tablets
Best for
  • Daily antioxidant and immune support
  • Collagen support
  • Buying a large serving supply

Pros

  • 1000 mg calcium ascorbate
  • Clear 120 mg calcium disclosure
  • 200 mg citrus bioflavonoids
  • Very large serving count

Cons

  • Specific bioflavonoids are not quantified
  • Tablet format may be hard to swallow
  • Focused formula does not provide broad micronutrient coverage

Warnings

  • The 1000 mg vitamin C serving may trigger loose stools or abdominal discomfort
  • People prone to calcium oxalate kidney stones should seek personalized guidance on sustained high-dose use
  • The serving contributes 120 mg of calcium

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.

.

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.

.

Customer satisfaction

66 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.

.

Value for money

98 Highest impact

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

.
Report analysis

Goals

Immunity
Immunity
Impact
Highest effect
A+ Goal FitA+ Strength of SupportC+ CoverageA+ Formula Quality
Vitamin C · 1000 mg

Buffered calcium ascorbate provides a substantial vitamin C amount for antioxidant defenses, barriers, and normal immune function. Citrus bioflavonoids offer a complementary antioxidant component with a clearly stated amount.

The formula is focused and gentler than plain ascorbic acid, with no hidden active blend. It still covers a narrow immune pathway and does not supply zinc, vitamin D, or broader barrier nutrients.

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 · 1000 mg

Buffered calcium ascorbate delivers a clearly stated 1000 mg of vitamin C with added citrus bioflavonoids. The combination supports antioxidant protection, collagen formation, and normal immune function while being gentler than unbuffered ascorbic acid.

Separate disclosure of vitamin C and calcium makes the active contribution easy to assess. The formula is focused and meaningful, although the tablet format may be less convenient for people who have difficulty swallowing tablets.

Study evidence
Vitamin C Supportive 56 studies
Anti-Inflammatory Support
Anti-Inflammatory Support
Impact
Highest effect
B Goal FitA Strength of SupportB CoverageA+ Formula Quality
Vitamin C · 1000 mg

Buffered calcium ascorbate provides meaningful antioxidant support with better stomach tolerance than unbuffered ascorbic acid. Citrus bioflavonoids complement vitamin C without obscuring its dose.

The fully disclosed amounts create a focused and practical antioxidant formula. Its main limitation is narrow pathway coverage rather than weak dosing or poor form quality.

Study evidence
Vitamin C Supportive 50 studies
Skin Health
Skin Health
Impact
Highest effect
B+ Goal FitA Strength of SupportC+ CoverageA Formula Quality
Vitamin C · 1000 mg

Buffered vitamin C provides strong collagen-synthesis and antioxidant support at a useful amount. Citrus bioflavonoids add complementary antioxidant coverage, though barrier and hydration pathways are absent.

Calcium ascorbate is clearly disclosed and may be gentler than plain ascorbic acid. The concise formula provides dependable depth without excessive complexity.

Study evidence
Vitamin C Supportive 53 studies
Vision Support
Vision Support
Impact
High effect
B Goal FitA Strength of SupportC- CoverageA- Formula Quality
Vitamin C · 1000 mg

Vitamin C provides relevant antioxidant support for the lens and retina, and the 1,000 mg amount is clearly stated. Its strongest clinical context is as one part of a broader ocular nutrient combination rather than as a complete vision formula.

Buffered calcium ascorbate may be gentler on the stomach than ordinary ascorbic acid. Citrus bioflavonoids add complementary antioxidant support, but the formula still lacks macular pigments, zinc, and omega-3s.

Study evidence
Vitamin C Disputed 24 studies

Ingredients

IngredientAmount per serving
Vitamin C (Calcium Ascorbate)
 1000 mg
Calcium (Calcium Ascorbate)
 120 mg
Bioflavonoids (Citrus Bioflavonoids)
 200 mg
Adults 18–50
Report overview
Vitamin C (Calcium Ascorbate) · 1000 mg OverallScore93
B+ Active Ingredient Quality & BioavailabilityA+ Dose, Safety & Label TransparencyA+ Value

The fully buffered calcium ascorbate form supplies a substantial amount of vitamin C while being gentler on the stomach than unbuffered ascorbic acid. Clear disclosure of both vitamin C and calcium supports confident dose assessment, and the citrus bioflavonoids add a complementary component without hiding the active amount. The large tablet count and efficient amount delivered per serving provide strong value, although the tablet format may be less convenient for people who prefer powders or liquids.

View ingredientView products
Loading alternative details
87 Performance

Ester-C with Citrus Bioflavonoids

American Health
<p>A full Ester-C amount and substantial citrus bioflavonoid complex preserve the original’s key buffered profile. The supplied quality and goal evidence is slightly more balanced, although the individual flavonoids are not broken out.</p>
89 Performance

Pure Buffered Calcium Ascorbate

NOW
<p>Pure calcium ascorbate provides a substantial buffered vitamin C amount with strong supplied quality evidence. It is a cleaner single-focus option than the original, though it does not replace the citrus bioflavonoid component.</p>
86 Performance

Ester-C Plus 1000 mg Vitamin C

Solgar
<p>A full Ester-C amount with a meaningful citrus bioflavonoid complex closely matches the original’s buffered potency. The supplied quality and goal profile is more even, while the flavonoid amount remains below the broadest original formulas.</p>
89 Budget

C-500 Calcium Ascorbate-C

NOW
<p>Calcium ascorbate keeps vitamin C buffered and adds a small citrus bioflavonoid amount at a lower serving cost. The active amounts are lower than in the original, so the value gain comes with less vitamin C and flavonoid coverage.</p>
87 Budget

100% Pure Vitamin C Powder

Swanson Premium Brand
<p>Single-ingredient ascorbic acid powder provides a full vitamin C amount at a lower serving cost. It lacks buffered calcium ascorbate and citrus bioflavonoids, so it favors economy and dose simplicity over the original’s broader profile.</p>
85 Budget

Gold C Vitamin C 1000 mg

California Gold Nutrition
<p>A focused ascorbic acid formula delivers a full vitamin C amount at a lower serving cost. The trade-off is the loss of the buffered form and citrus bioflavonoids found in the original.</p>
86 Value

Buffered Vitamin C + Citrus Bioflavonoids

Jarrow Formulas
<p>Buffered calcium ascorbate and a substantial bioflavonoid amount provide a useful balance of ingredient fit and value. The vitamin C amount is lower than in the original, while the flavonoid coverage remains meaningful.</p>
80 Value

Supreme C Complex

Swanson Premium Brand
<p>Vitamin C, a substantial citrus bioflavonoid complex, and added rutin create broad flavonoid support with favorable value. Ascorbic acid replaces the original’s buffered form, so stomach comfort may be a more important trade-off.</p>
87 Value

Pure Buffered Magnesium Ascorbate

NOW
<p>Buffered magnesium ascorbate supplies a substantial vitamin C amount with favorable value and adds magnesium from the same compound. It omits citrus bioflavonoids, but keeps a buffered mineral ascorbate form while lowering formula complexity.</p>
Report alternatives

Sources

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

  1. 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
  2. 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
  3. 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
  4. 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
  5. 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
  6. 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
  7. 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
  8. 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
  9. 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
  10. 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
  11. 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
  12. 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
  13. 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
  14. 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
  15. 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
  16. 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
  17. 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
  18. 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
  19. 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
  20. 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
  21. 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
  22. 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
  23. Nutritional modulation of cataract.
    Weikel KA; Garber C; Baburins A; Taylor A · Nutrition reviews · 2014
    Narrative reviewVision Support forVitamin C
  24. 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
  25. 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