21st Century Vitamin D3 2000 IU
vs
Metagenics Bone Builder® with Magnesium
Supplement Comparison

  • Vitamin D: 21st Century Vitamin D3 2000 IU has 3.3× more
  • The image below shows:
    • Side-by-side charts with label nutrient amounts, per serving
    • Nutrient forms as listed on the label
    • 8 nutrients compared
Bar chart: per-serving label amounts and listed forms for 21st Century Vitamin D3 2000 IU vs Metagenics Bone Builder® with Magnesium.

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Frequently asked questions

Which active ingredients does 21st Century Vitamin D3 2000 IU have?

  • Vitamin D appears as Cholecalciferol (D3)

Which active ingredients does Metagenics Bone Builder® with Magnesium have?

  • Vitamin D appears as Cholecalciferol (D3)
  • Calcium appears as Calcium (MCHC, dicalcium phosphate)
  • Phosphorus appears as Phosphorus (MCHC, dicalcium phosphate)
  • Magnesium appears as Magnesium (citrate, aspartate, bis-glycinate)
  • Microcrystalline Hydroxyapatite Concentrate (MCHC)

Which categories do 21st Century Vitamin D3 2000 IU and Metagenics Bone Builder® with Magnesium belong to?

  • Single Vitamin
  • Joint Formula

What health concerns do 21st Century Vitamin D3 2000 IU and Metagenics Bone Builder® with Magnesium address?

  • Brain, Focus & Cognitive Function
  • General Health
  • Heart & Cardiovascular Health
  • Immune System Support
  • Joint & Bone Health
  • Muscle Support
  • Sleep Quality
  • Stress Management

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

  • 21st Century Vitamin D3 2000 IU has the highest total amount of Vitamin D: 2000 IU per serving

How do the serving sizes compare between the two supplements?

  • Serving size:
    • 21st Century Vitamin D3 2000 IU: 1 softgel
    • Metagenics Bone Builder® with Magnesium: 3 tablets
  • Vitamin D
    • This supplement has 2000 IU
    • Recommended Dietary Allowance in men: 600 IU
    • Recommended Dietary Allowance in women: 600 IU
    • Tolerable Upper Intake Level: 4000 IU
  • Vitamin D
    • This supplement has 600 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 620 mg
    • Recommended Dietary Allowance in men: 1000 mg
    • Recommended Dietary Allowance in women: 1000 mg
    • Tolerable Upper Intake Level: 2500 mg
  • Phosphorus
    • This supplement has 350 mg
    • Recommended Dietary Allowance in men: 700 mg
    • Recommended Dietary Allowance in women: 700 mg
    • Tolerable Upper Intake Level: 4000 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