21st Century Magnesium
vs
Douglas Laboratories Ascorbplex 1000™ (Buffered Vitamin C)
Supplement Comparison

  • Magnesium: 21st Century Magnesium has 625× more
  • Calcium: Douglas Laboratories Ascorbplex 1000™ (Buffered Vitamin C) has 38% more
  • The image below shows:
    • Side-by-side charts with label nutrient amounts, per serving
    • Nutrient forms as listed on the label
    • 10 nutrients compared
Bar chart: per-serving label amounts and listed forms for 21st Century Magnesium vs Douglas Laboratories Ascorbplex 1000™ (Buffered Vitamin C).

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Frequently asked questions

Which active ingredients does 21st Century Magnesium have?

  • Calcium appears as Calcium Carbonate
  • Magnesium appears as Magnesium Oxide

Which active ingredients does Douglas Laboratories Ascorbplex 1000™ (Buffered Vitamin C) have?

  • Vitamin C appears as Calcium, Magnesium, Potassium Ascorbates and Ascorbic Acid
  • Calcium appears as Calcium Ascorbate and Carbonate Complex
  • Magnesium appears as Magnesium Ascorbate and Oxide Complex
  • Potassium appears as Potassium Ascorbate and Chloride Complex
  • Blend appears as Citrus Pectin and Citrus Bioflavonoids Complex

Which categories do 21st Century Magnesium and Douglas Laboratories Ascorbplex 1000™ (Buffered Vitamin C) belong to?

  • Mineral Complex
  • Single Vitamin

What health concerns do 21st Century Magnesium and Douglas Laboratories Ascorbplex 1000™ (Buffered Vitamin C) address?

  • Muscle Support
  • General Health
  • Joint & Bone Health
  • Sleep Quality
  • Stress Management
  • Antioxidant Support
  • Immune System Support

Which product has a higher amount of Magnesium per serving?

  • 21st Century Magnesium has the highest total amount of Magnesium: 250 mg per serving

Which product has a higher amount of Calcium per serving?

  • Douglas Laboratories Ascorbplex 1000™ (Buffered Vitamin C) has the highest total amount of Calcium: 90 mg per serving

How do the serving sizes compare between the two supplements?

  • Serving size:
    • 21st Century Magnesium: 1 tablet
    • Douglas Laboratories Ascorbplex 1000™ (Buffered Vitamin C): 1 tablet
  • Calcium
    • This supplement has 65 mg
    • Recommended Dietary Allowance in men: 1000 mg
    • Recommended Dietary Allowance in women: 1000 mg
    • Tolerable Upper Intake Level: 2500 mg
  • 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
  • Calcium
    • This supplement has 90 mg
    • Recommended Dietary Allowance in men: 1000 mg
    • Recommended Dietary Allowance in women: 1000 mg
    • Tolerable Upper Intake Level: 2500 mg
  • Potassium
    • This supplement has 60 mg
    • Adequate Intake in men: 3400 mg
    • Adequate Intake in women: 2600 mg
    • Tolerable Upper Intake Level: Not established

Last updated: February 19, 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