21st Century Calcium Magnesium Zinc + D3
vs
21st Century Biotin 10,000 mcg
Supplement Comparison

  • Calcium: 21st Century Calcium Magnesium Zinc + D3 has 10× more
  • The image below shows:
    • Side-by-side charts with label nutrient amounts, per serving
    • Nutrient forms as listed on the label
    • 9 nutrients compared
Bar chart: per-serving label amounts and listed forms for 21st Century Calcium Magnesium Zinc + D3 vs 21st Century Biotin 10,000 mcg.

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Frequently asked questions

Which active ingredients does 21st Century Calcium Magnesium Zinc + D3 have?

  • Vitamin D appears as Cholecalciferol (D3)
  • Calcium appears as Calcium Carbonate
  • Magnesium appears as Magnesium Oxide
  • Zinc appears as Zinc Oxide

Which active ingredients does 21st Century Biotin 10,000 mcg have?

  • Vitamin B7 (Biotin) appears as D-Biotin
  • Calcium appears as Calcium Carbonate

Which categories do 21st Century Calcium Magnesium Zinc + D3 and 21st Century Biotin 10,000 mcg belong to?

  • Mineral Complex
  • Single Vitamin

What health concerns do 21st Century Calcium Magnesium Zinc + D3 and 21st Century Biotin 10,000 mcg address?

  • Muscle Support
  • Brain, Focus & Cognitive Function
  • Eye Health
  • General Health
  • Heart & Cardiovascular Health
  • Immune System Support
  • Joint & Bone Health
  • Men's Health
  • Skin, Hair & Nail Health
  • Sleep Quality
  • Stress Management
  • Energy & Metabolism

Which product has a higher amount of Calcium per serving?

  • 21st Century Calcium Magnesium Zinc + D3 has the highest total amount of Calcium: 1000 mg per serving

How do the serving sizes compare between the two supplements?

  • Serving size:
    • 21st Century Calcium Magnesium Zinc + D3: 3 tablets
    • 21st Century Biotin 10,000 mcg: 1 tablet
  • Vitamin D
    • This supplement has 400 IU
    • Recommended Dietary Allowance in men: 600 IU
    • Recommended Dietary Allowance in women: 600 IU
    • Tolerable Upper Intake Level: 4000 IU
  • Calcium
    • This supplement has 1000 mg
    • Recommended Dietary Allowance in men: 1000 mg
    • Recommended Dietary Allowance in women: 1000 mg
    • Tolerable Upper Intake Level: 2500 mg
  • Zinc
    • This supplement has 15 mg
    • Recommended Dietary Allowance in men: 11 mg
    • Recommended Dietary Allowance in women: 8 mg
    • Tolerable Upper Intake Level: 40 mg
  • Vitamin B7 (Biotin)
    • This supplement has 10000 mcg
    • Adequate Intake in men: 30 mcg
    • Adequate Intake in women: 30 mcg
    • Tolerable Upper Intake Level: Not established
  • Calcium
    • This supplement has 96 mg
    • Recommended Dietary Allowance in men: 1000 mg
    • Recommended Dietary Allowance in women: 1000 mg
    • Tolerable Upper Intake Level: 2500 mg

Last updated: February 5, 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