Thorne Ascorbic Acid
vs
21st Century Vitamin C
Supplement Comparison

  • Vitamin C: Thorne Ascorbic Acid has 2.0× more
  • The image below shows:
    • Side-by-side charts with label nutrient amounts, per serving
    • Nutrient forms as listed on the label
    • 3 nutrients compared
Bar chart: per-serving label amounts and listed forms for Thorne Ascorbic Acid vs 21st Century Vitamin C.

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Frequently asked questions

Which active ingredients does Thorne Ascorbic Acid have?

  • Vitamin C appears as Ascorbic Acid

Which active ingredients does 21st Century Vitamin C have?

  • Vitamin C appears as Ascorbic Acid
  • Calcium appears as Calcium Carbonate

Which categories do Thorne Ascorbic Acid and 21st Century Vitamin C belong to?

  • Single Vitamin

What health concerns do Thorne Ascorbic Acid and 21st Century Vitamin C address?

  • Antioxidant Support
  • Immune System Support
  • Skin, Hair & Nail Health

Which product has a higher amount of Vitamin C per serving?

  • Thorne Ascorbic Acid has the highest total amount of Vitamin C: 1000 mg per serving

How do the serving sizes compare between the two supplements?

  • Serving size:
    • Thorne Ascorbic Acid: 1 capsule
    • 21st Century Vitamin C: 1 tablet
  • Vitamin C
    • This supplement has 1000 mg
    • Recommended Dietary Allowance in men: 90 mg
    • Recommended Dietary Allowance in women: 75 mg
    • Tolerable Upper Intake Level: 2000 mg
  • Vitamin C
    • This supplement has 500 mg
    • Recommended Dietary Allowance in men: 90 mg
    • Recommended Dietary Allowance in women: 75 mg
    • Tolerable Upper Intake Level: 2000 mg
  • Calcium
    • This supplement has 30 mg
    • Recommended Dietary Allowance in men: 1000 mg
    • Recommended Dietary Allowance in women: 1000 mg
    • Tolerable Upper Intake Level: 2500 mg

Last updated: February 12, 2026

  • Sources & Methodology: Nutrient data and forms are taken directly from Supplement Facts labels. Reviewed and standardized by the VIOscan Research Team. Learn more on the Methodology page.
  • We show the Recommended Dietary Allowance (RDA) when available. If no RDA exists, we show the Adequate Intake (AI). Tolerable Upper Intake Levels (UL) are used for upper limits. Unless otherwise noted, RDAs shown correspond to healthy adults aged 19–50 years and are sex-specific. Separate values exist for 51–70 years and >70 years, and pregnancy and lactation are excluded. All values come from the Dietary Reference Intakes (DRIs) published by the National Academies of Sciences, Engineering, and Medicine (NASEM), Food and Nutrition Board (FNB).
  • Transparency: We’re funded by our users. We don’t have sponsors or affiliate links, and we don’t sell supplements.
  • Editorial standards: we provide independent, impartial and objective data analysis.
  • This analysis is for educational purposes only. It is not a substitute for medical advice.
  • Questions? Read our Frequently Asked Questions or contact us, we’re here to help.
  • See an error? Report it through our Contact page.
  • Author: VIOscan Research Team