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C Extra + Quercetin

4.8
★ ★ ★ ★ ★
(2184 ratings)
Vitamin C 500 mg
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Score84
A focused, well-disclosed vitamin C and quercetin pairing with useful antioxidant breadth. Delivery is basic for both actives.
How scoring works
Capsule
Quantity:60 Capsule(s) • (60 servings)
Goals:
General Health
Skin Health
Anti-Inflammatory Support
Immunity

Score 84

A focused, well-disclosed vitamin C and quercetin pairing with useful antioxidant breadth. Delivery is basic for both actives.
How scoring works
$13.97($0.23 per serving)
Vitacost
$ 13.97
iHerb
$ 13.97
Amazon
$ 13.97
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Analysis

Vitamin C and quercetin provide complementary antioxidant support with both amounts clearly disclosed. The combination adds meaningful breadth without becoming a crowded multi-ingredient formula.

The ascorbic acid form is unbuffered and may be less comfortable for sensitive users. Quercetin is substantial, though no enhanced-absorption form or delivery feature is described.

The pairing is especially relevant to antioxidant and inflammatory-balance goals, while still supporting collagen and normal immune function. It does not replace a broader vision, skin-barrier, or foundational nutrition formula.

Who is it for
  • Adults seeking vitamin C with meaningful quercetin
  • Users wanting a concise antioxidant combination
  • People focused on inflammatory-balance support
Best for
  • Complementary antioxidant support
  • Collagen and immune nutrition
  • Two-pathway inflammatory-balance support

Pros

  • Substantial disclosed quercetin amount
  • Practical vitamin C serving
  • Focused two-active design

Cons

  • Vitamin C is unbuffered
  • No enhanced quercetin absorption detail
  • Not a comprehensive vision or skin formula

Warnings

  • Unbuffered ascorbic acid may cause digestive discomfort
  • Quercetin may interact with some medications, so users taking prescription drugs should review compatibility with a clinician or pharmacist
  • People prone to calcium oxalate kidney stones should consider total supplemental vitamin C intake

Nutrient quality

90 Highest impact

Vitamin C and quercetin form a coherent antioxidant pairing. Ascorbic acid is standard, while the quercetin form is identified only broadly as bioflavonoids.

Ingredient transparency

89 Highest impact

Specific amounts are listed for vitamin C and quercetin. The complete inactive-ingredient statement is not supplied.

Customer satisfaction

72 High impact

Feedback volume is substantial enough to make the aggregate rating more stable. No complaint text is supplied, so repetitive negative themes cannot be assessed.

Value for money

82 Highest impact

The formula contains no evident low-value active extras. Relative serving cost is moderate rather than especially low.

Report analysis

Goals

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

Vitamin C and quercetin offer a logical antioxidant pairing with clear amounts. The vitamin C amount is useful, while quercetin adds targeted breadth without turning the formula into an unfocused blend.

Generic ascorbic acid is established but lacks buffering or another absorption feature. Full dose disclosure and the streamlined two-ingredient design make the formula easy to assess.

Study evidence
Vitamin C Supportive 56 studies
Skin Health
Skin Health
Impact
Highest effect
B+ Goal FitB Strength of SupportC+ CoverageA Formula Quality
Vitamin C · 500 mg

The focused formula supports collagen synthesis and antioxidant protection in the skin. Ascorbic acid is paired with a substantial disclosed quercetin amount.

It does not provide collagen peptides, barrier lipids, or hydration-focused actives. The two-ingredient antioxidant formula remains focused.

Study evidence
Vitamin C Supportive 53 studies
Anti-Inflammatory Support
Cellular Defense
Anti-Inflammatory Support
Impact
High effect
B Goal FitB- Strength of SupportB- CoverageA Formula Quality
Vitamin C · 500 mg

Standard ascorbic acid supplies antioxidant support that may help limit oxidative stress linked with inflammatory signaling. The disclosed 500 mg serving reaches a practical Vitamin C amount.

Quercetin adds a complementary flavonoid pathway and is present at a meaningful 250 mg amount. The Vitamin C remains unbuffered, and the quercetin form has no enhanced-absorption detail.

Study evidence
Vitamin C Supportive 50 studies
Immunity
Immunity
Impact
High effect
B+ Goal FitC+ Strength of SupportD+ CoverageB+ Formula Quality
Vitamin C · 500 mg

Vitamin C provides relevant support for immunity. Vitamin C is a foundational and direct-acting nutrient for immune cell function and antioxidant protection.

The 500 mg Vitamin C dose is practical and clearly disclosed. Generic unbuffered ascorbic acid limits delivery quality and may be less comfortable for sensitive users.

Study evidence
Vitamin C Supportive 53 studies
Vision Support
Macular and Blue Light Defense
Vision Support
Impact
Moderate effect
F Goal FitB- Strength of SupportD CoverageB Formula Quality
Vitamin C · 500 mg

Vitamin C and quercetin provide a focused antioxidant combination with general relevance to ocular tissues. The formula lacks macular pigments, zinc, copper, vitamin E, and DHA.

Both active amounts are clearly disclosed, and quercetin is substantial. Antioxidant depth remains narrower than a targeted vision formulation.

Study evidence
Vitamin C Disputed 24 studies

Ingredients

IngredientAmount per serving
Vitamin C (Ascorbic Acid)
 500 mg
Quercetin (Bioflavonoids)
 250 mg
Gluten Free Adults 18–50 Vegan Dairy Free Sugar Free Vegetarian
Report overview
Vitamin C (Ascorbic Acid) · 500 mg OverallScore55
F Active Ingredient Quality & BioavailabilityA Dose, Safety & Label TransparencyF Value

The 500 mg Vitamin C dose is practical and clearly disclosed. Generic unbuffered ascorbic acid limits delivery quality and may be less comfortable for sensitive users. Quercetin adds a meaningful companion ingredient, though Vitamin C cost efficiency is only borderline.

View ingredientView products
Loading alternative details
89 Performance

Ester-C Plus 1000 mg Vitamin C

Solgar
<p>The ingredient profile is a stronger fit for focused vitamin C support, supplying 1000 mg of vitamin C as Ester-C with calcium and citrus bioflavonoids. Compared with the original’s Ascorbic Acid, the mineral ascorbate form may be gentler and is more clearly aligned with focused vitamin C use.</p>
89 Performance

Buffered Gold C

California Gold Nutrition
<p>The ingredient profile is a stronger fit for focused vitamin C support, supplying 1000 mg of vitamin C as Sodium Ascorbate. Compared with the original’s Ascorbic Acid, the mineral ascorbate form may be gentler and is more clearly aligned with focused vitamin C use.</p>
88 Performance

C

Swanson
<p>The ingredient profile is a stronger fit for focused vitamin C support, supplying 1000 mg of vitamin C as Calcium Ascorbate with calcium and citrus bioflavonoids. Compared with the original’s Ascorbic Acid, the mineral ascorbate form may be gentler and is more clearly aligned with focused vitamin C use.</p>
89 Budget

Pure Buffered Calcium Ascorbate

NOW
<p>A lower cost per serving makes this a practical budget alternative, while it supplies 890 mg of vitamin C as Calcium Ascorbate with calcium. The vitamin C amount matches or exceeds the original's 500 mg serving. Its mineral ascorbate form may also be gentler than the original’s plain ascorbic acid.</p>
88 Budget

Sodium Ascorbate

NutriBiotic Immunity
<p>A lower cost per serving makes this a practical budget alternative, while it supplies 1100 mg of vitamin C as Sodium Ascorbate. The vitamin C amount matches or exceeds the original's 500 mg serving. Its mineral ascorbate form may also be gentler than the original’s plain ascorbic acid.</p>
87 Budget

100% Pure Vitamin C Powder

Swanson Premium Brand
<p>A lower cost per serving makes this a practical budget alternative, while it supplies 1000 mg of vitamin C as Ascorbic Acid. The vitamin C amount matches or exceeds the original's 500 mg serving.</p>
93 Value

Pure Buffered Magnesium Ascorbate

NOW
<p>Strong serving value is paired with 820 mg of vitamin C as Magnesium Ascorbate with magnesium. It matches or exceeds the original’s vitamin C amount and adds a potentially gentler mineral ascorbate form, balancing cost-effectiveness with a useful ingredient profile.</p>
93 Value

Sodium Ascorbate Capsules

NutriBiotic Immunity
<p>Strong serving value is paired with 850 mg of vitamin C as Sodium Ascorbate. It matches or exceeds the original’s vitamin C amount and adds a potentially gentler mineral ascorbate form, balancing cost-effectiveness with a useful ingredient profile.</p>
92 Value

Ester-C 500 mg With Citrus Bioflavoinds

American Health
<p>Strong serving value is paired with 1000 mg of vitamin C as Ester-C Calcium Ascorbate with calcium and citrus bioflavonoids. It matches or exceeds the original’s vitamin C amount and adds a potentially gentler mineral ascorbate form, balancing cost-effectiveness with a useful ingredient profile.</p>
Report alternatives

Sources

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

  1. Mortality in randomized trials of antioxidant supplements for primary and secondary prevention: systematic review and meta-analysis.
    Bjelakovic G; Nikolova D; Gluud LL; Simonetti RG; Gluud C · JAMA · 2007
    Meta-analysis232,606 participants68 studies pooledGeneral Health forVitamin C
  2. Vitamin C intake and multiple health outcomes: an umbrella review of systematic reviews and meta-analyses.
    Xu K; Peng R; Zou Y; Jiang X; Sun Q; Song C · International journal of food sciences and nutrition · 2022
    Meta-analysis76 studies pooledGeneral Health forVitamin C
  3. 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
  4. 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
  5. 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
  6. 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
  7. 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
  8. 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
  9. 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
  10. 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
  11. 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
  12. 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
  13. 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
  14. 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
  15. 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
  16. 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
  17. 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
  18. 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
  19. 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
  20. 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
  21. 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
  22. 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
  23. 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
  24. 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
  25. Nutritional modulation of cataract.
    Weikel KA; Garber C; Baburins A; Taylor A · Nutrition reviews · 2014
    Narrative reviewVision Support forVitamin C
  26. 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
  27. 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