Product Image

AlphaSorb-C 500

NOW
4.8
★ ★ ★ ★ ★
(413 ratings)
Vitamin C 500 mg
Rutin 25 mg
Acerola 25 mg
Flavonoid (mixture) 100 mg
Product Image
Score80
A practical buffered vitamin C formula with strong form quality and everyday value, though its botanical extras are small and partly wrapped in a support blend.
How scoring works
Quantity:180 Capsule(s) • (180 servings)
Goals:
General Health
Immunity
Skin Health
Vision Support
Anti-Inflammatory Support

Score 80

A practical buffered vitamin C formula with strong form quality and everyday value, though its botanical extras are small and partly wrapped in a support blend.
How scoring works
$20.18($0.11 per serving)
Daily Vita
$ 20.30
iHerb
$ 21.43
Pure Formulas
$ 20.18
Vitacost
$ 22.49
Report prices

Analysis

Buffered calcium ascorbate with threonic acid supplies meaningful vitamin C for antioxidant, collagen, and immune support. The form is a good fit for people who find ordinary ascorbic acid too harsh.

Bioflavonoids, acerola, rose hips, and rutin add related plant compounds without distracting from the main active. Their amounts are modest, however, and they should not be mistaken for targeted botanical doses.

The main nutrient amounts are clear, while the support-blend name introduces some unnecessary complexity. The large serving count and focused design make it practical for routine vitamin C use.

Who is it for
  • Adults wanting buffered vitamin C
  • People with acid-sensitive stomachs
  • Users seeking a long-term daily supply
Best for
  • Routine antioxidant support
  • Normal collagen production
  • Foundational immune support

Pros

  • Stomach-friendly calcium ascorbate
  • Useful vitamin C amount
  • Good practical value for routine use

Cons

  • Proprietary support-blend labeling
  • Low acerola amount
  • Rutin is modestly dosed

Warnings

  • Include the calcium contribution when tracking supplemental calcium
  • The botanical powders are not substitutes for dedicated acerola or rutin supplements
  • Avoid stacking with other high-vitamin-C products without a clear need

Nutrient quality

89 Highest impact

Buffered calcium ascorbate with threonic acid provides a well-regarded delivery form. Vitamin C is meaningfully dosed, while acerola, rose hips, and rutin remain minor additions.

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Ingredient transparency

72 High impact

Most active amounts are clear, but the branded transport complex is not fully separated. The supplied data does not include a complete inactive ingredient list.

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Customer satisfaction

69 High impact

The aggregate satisfaction measure is strong enough to support a favorable first impression. Missing feedback themes leave repeat complaints and purpose fit uncertain despite adequate volume.

.

Value for money

88 Highest impact

The low price is well matched to the buffered form and meaningful core dose. Each serving provides excellent value for enhanced vitamin C delivery.

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Report analysis

Goals

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

Buffered vitamin C provides well-dosed support for antioxidant defenses, collagen production, and normal immune function. Bioflavonoids and related plant compounds reinforce the same general pathway.

The formula offers useful depth but does not cover the full range of general wellness needs. Its proprietary support blend is partly explained by listed components, though the presentation remains more complex than necessary.

Study evidence
Vitamin C Supportive 56 studies
Immunity
Immunity
Impact
Highest effect
A Goal FitA Strength of SupportC+ CoverageB Formula Quality
Vitamin C · 500 mg

Vitamin C directly supports immune cells, barrier defenses, and antioxidant control at a meaningful amount. Buffered calcium ascorbate with threonic acid provides a stomach-friendly delivery approach.

Bioflavonoids, acerola, rose hips, and rutin add related antioxidant support, but most are modest additions. The proprietary support blend reduces transparency and makes the broad formula less streamlined.

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

Buffered vitamin C supports collagen synthesis and antioxidant defense in a stomach-friendly form. Bioflavonoids, rutin, acerola, and rose hips may add complementary oxidative protection.

The main vitamin amount is practical and clearly stated, while calcium ascorbate improves tolerability. The proprietary support blend makes some component amounts harder to interpret and does not add direct hydration or structural peptides.

Study evidence
Vitamin C Supportive 53 studies
Vision Support
Vision Support
Impact
High effect
B Goal FitA Strength of SupportC- CoverageB- Formula Quality
Vitamin C · 500 mg

Vitamin C supplies a well-established ocular antioxidant and is part of clinically studied eye-nutrient combinations. Used alone, it cannot reproduce the broader protection of a complete AREDS2-style formula.

Buffered calcium ascorbate with threonic acid offers strong form quality, although a proprietary support blend obscures some details. The focused antioxidant design does not provide macular pigments, omega-3 fats, or zinc for broader eye support.

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

Buffered vitamin C provides meaningful antioxidant support, while rutin and citrus bioflavonoids add modest complementary activity. The vitamin C amount is well targeted for regular use.

Threonic-acid-enhanced calcium ascorbate offers a practical, stomach-friendly form. Several supporting ingredients are low-dose, and the large proprietary support blend limits confidence in their individual contributions.

Study evidence
Rutin Supportive 6 studies
Vitamin C Supportive 50 studies

Ingredients

IngredientAmount per serving
Vitamin C (Threonic Acid enhanced buffered Calcium Ascorbate)
 500 mg
Calcium (Calcium Ascorbate)
 60 mg
Transport C-PLUS
650 mg
Citrus Bioflavonoid Complex
100 mg
Acerola powder
25 mg
Rose Hips
25 mg
Rutin powder (Sophora japonica)
 25 mg
Gluten Free Adults 18–50 Vegan Dairy Free Vegetarian
Report overview
Vitamin C (Threonic Acid enhanced buffered Calcium Ascorbate) · 500 mg OverallScore93
B+ Active Ingredient Quality & BioavailabilityA+ Dose, Safety & Label TransparencyA+ Value

Buffered calcium ascorbate with threonic acid offers a stomach-friendly form and a well-targeted 500 mg serving. Separate calcium and vitamin C amounts improve clarity despite the added proprietary support blend. Its enhanced formula remains economical per gram.

View ingredientView products
Rutin (Sophora japonica) · 25 mg OverallScore61
B- Active Ingredient Quality & BioavailabilityD- Dose, Safety & Label TransparencyB Value

Sophora japonica gives the rutin a clear source, though the generic powder has no purity or standardization details. The exact dose is disclosed outside the proprietary blend but remains too low for targeted capillary support. Its favorable cost per active amount reflects an inexpensive serving with broader buffered vitamin C ingredients.

View ingredientView products
Acerola · 25 mg OverallScore25
F Active Ingredient Quality & BioavailabilityF Dose, Safety & Label TransparencyD+ Value

The 25 mg acerola powder amount is far below a potent serving and has no active-marker standardization. Buffered calcium ascorbate is the main vitamin C source, making acerola a token component of a broader formula. Its low serving cost is less meaningful for shoppers specifically seeking substantial acerola.

View ingredientView products
Loading alternative details
87 Performance

Ester-C with Citrus Bioflavonoids

American Health
<p>A 1,000 mg buffered vitamin C serving and 400 mg citrus bioflavonoid complex provide more substantial core coverage than the original. It does not preserve the separate acerola, rose hips, and rutin ingredients, but the simpler active profile is easier to assess.</p>
86 Performance

C

Swanson
<p>Calcium ascorbate doubles the original's vitamin C amount while retaining 200 mg of citrus bioflavonoids in a concise formula. The original offers more botanical variety, but most of those supporting ingredients are only 25 mg each.</p>
86 Performance

Ester-C Plus 1000 mg Vitamin C

Solgar
<p>Ester-C provides a clearly named buffered 1,000 mg vitamin C serving with 200 mg of citrus bioflavonoids. It offers more concentrated core support than the original, though it lacks separate acerola, rose hips, and rutin.</p>
80 Budget

Supreme C Complex

Swanson Premium Brand
<p>A lower-cost serving preserves 500 mg of vitamin C and provides 500 mg of citrus bioflavonoids, far more than the original's listed bioflavonoid amount. It uses unbuffered ascorbic acid and leaves out calcium ascorbate, acerola, rose hips, and the transport blend.</p>
84 Budget

Ester-C 500 mg With Citrus Bioflavoinds

American Health
<p>Buffered vitamin C and a broad citrus bioflavonoid complex cost less per serving while providing more main vitamin C than the original. The complex names several components but does not clarify their individual shares, which limits direct dose comparison.</p>
84 Budget

Ester-C 24 Hour Immune Support 1000 mg

NatureSmart
<p>A much lower recurring cost provides twice the vitamin C in buffered calcium ascorbate form plus citrus bioflavonoids. The focused formula omits the original's separate acerola, rose hips, rutin, and threonic-acid-enhanced blend.</p>
82 Value

Buffered C-1000 Complex

NOW
<p>The same brand offers twice the buffered vitamin C, more citrus bioflavonoids, and larger acerola and rutin amounts at a similar serving cost. The formula drops rose hips and the named threonic-acid enhancement, but its disclosed active amounts provide stronger practical value.</p>
82 Value

Ester-C Plus 1000 mg Vitamin C

Solgar
<p>A modest increase in serving cost buys twice the buffered vitamin C and twice the citrus bioflavonoids. Acerola, rose hips, and rutin remain small, yet the stronger main dose improves value for a vitamin C-focused user.</p>
84 Value

Ester-C 500 mg

American Health
<p>Buffered vitamin C and 400 mg of citrus bioflavonoids provide a more concentrated core formula with a still-low recurring cost. It leaves out the original's separate botanical additions, but those additions were present at modest amounts.</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. Vitamin C supplementation in kidney failure: effect on uraemic symptoms.
    Singer RF · Nephrology, dialysis, transplantation : official publication of the European Dialysis and Transplant Association - European Renal Association · 2011
    Randomized trial99 participantsGeneral Health forVitamin C
  4. 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
  5. 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
  6. 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
  7. 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
  8. 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
  9. 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
  10. The effects of rutin flavonoid supplement on glycemic status, lipid profile, atherogenic index of plasma, brain-derived neurotrophic factor (BDNF), some serum inflammatory, and oxidative stress factors in patients with type 2 diabetes mellitus: A double-blind, placebo-controlled trial.
    Bazyar H; Moradi L; Zaman F; Zare Javid A · Phytotherapy research : PTR · 2023
    Randomized trial50 participantsAnti-Inflammatory Support forRutin
  11. Rutin ameliorates inflammation and improves metabolic function: A comprehensive analysis of scientific literature.
    Muvhulawa N; Dludla PV; Ziqubu K; Mthembu SXH; Mthiyane F; Nkambule BB; Mazibuko-Mbeje SE · Pharmacological research · 2022
    Systematic reviewAnti-Inflammatory Support forRutin
  12. Rutin-loaded chitosan microspheres: Characterization and evaluation of the anti-inflammatory activity.
    Cosco D; Failla P; Costa N; Pullano S; Fiorillo A; Mollace V; Fresta M; Paolino D · Carbohydrate polymers · 2018
    OtherAnti-Inflammatory Support forRutin
  13. Oral enzyme combination therapy reduces systemic inflammation, urinary CTXII and pain in knee osteoarthritis: a proof-of-mechanism, randomised, crossover, double-blind, placebo-controlled trial.
    Henrotin Y; Pap T; Lieten S; Badot V; Dubuc JE; Urbin-Choffray D; von Eynatten M; Johansen OE; Rau S; Brabants K · RMD open · 2025
    Randomized trial45 participantsAnti-Inflammatory Support forRutin
  14. The Impact of the Combination of Proteolytic Enzyme and Rutin on the Post-operative Management of Inflammation: A Randomized, Controlled, Double-Blind, Comparative Clinical Trial
    Rathi PC, Rathi CL, Risbud SP, Ganu GP · Cureus · 2024
    Randomized trial65 participantsAnti-Inflammatory Support forRutin
  15. 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
  16. 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
  17. 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
  18. 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
  19. 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
  20. 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
  21. 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
  22. 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
  23. 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
  24. 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
  25. 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
  26. 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
  27. 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
  28. 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
  29. 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
  30. 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
  31. 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
  32. 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
  33. 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
  34. Nutritional modulation of cataract.
    Weikel KA; Garber C; Baburins A; Taylor A · Nutrition reviews · 2014
    Narrative reviewVision Support forVitamin C
  35. 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
  36. 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