NOW Foods Vitamin D-3 400 IU
vs
NOW Foods Calcium Citrate
Supplement Comparison

  • Vitamin D: NOW Foods Calcium Citrate has 88% more
  • The image below shows:
    • Side-by-side charts with label nutrient amounts, per serving
    • Nutrient forms as listed on the label
    • 12 nutrients compared
Bar chart: per-serving label amounts and listed forms for NOW Foods Vitamin D-3 400 IU vs NOW Foods Calcium Citrate.

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Frequently asked questions

Which active ingredients does NOW Foods Vitamin D-3 400 IU have?

  • Vitamin D appears as Cholecalciferol (D3)

Which active ingredients does NOW Foods Calcium Citrate have?

  • Vitamin D appears as Ergocalciferol (D2)
  • Calcium appears as Calcium Citrate
  • Magnesium appears as Magnesium Oxide
  • Zinc appears as Zinc Amino Acid Chelate
  • Copper appears as Copper Amino Acid Chelate
  • Manganese appears as Manganese Amino Acid Chelate

Which categories do NOW Foods Vitamin D-3 400 IU and NOW Foods Calcium Citrate belong to?

  • Single Vitamin
  • Mineral Complex
  • Single Mineral

What health concerns do NOW Foods Vitamin D-3 400 IU and NOW Foods Calcium Citrate address?

  • Brain, Focus & Cognitive Function
  • General Health
  • Heart & Cardiovascular Health
  • Immune System Support
  • Joint & Bone Health

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

  • NOW Foods Calcium Citrate has the highest total amount of Vitamin D: 750 IU per serving

How do the serving sizes compare between the two supplements?

  • Serving size:
    • NOW Foods Vitamin D-3 400 IU: 1 softgel
    • NOW Foods Calcium Citrate: 3 capsules
  • 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
  • Vitamin D
    • This supplement has 750 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 450 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 11 mg
    • Recommended Dietary Allowance in men: 11 mg
    • Recommended Dietary Allowance in women: 8 mg
    • Tolerable Upper Intake Level: 40 mg
  • Copper
    • This supplement has 0.75 mg
    • Recommended Dietary Allowance in men: 0.9 mg
    • Recommended Dietary Allowance in women: 0.9 mg
    • Tolerable Upper Intake Level: 10 mg
  • Manganese
    • This supplement has 4 mg
    • Adequate Intake in men: 2.3 mg
    • Adequate Intake in women: 1.8 mg
    • Tolerable Upper Intake Level: 11 mg

Last updated: February 2, 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