NOW Foods C-1000 Zinc & D-3
vs
Douglas Laboratories Vitamin D 1000 IU
Supplement Comparison

  • Vitamin D: NOW Foods C-1000 Zinc & D-3 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
    • 5 nutrients compared
Bar chart: per-serving label amounts and listed forms for NOW Foods C-1000 Zinc & D-3 vs Douglas Laboratories Vitamin D 1000 IU.

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Frequently asked questions

Which active ingredients does NOW Foods C-1000 Zinc & D-3 have?

  • Vitamin C appears as Ascorbic Acid
  • Vitamin D appears as Cholecalciferol (D3)
  • Zinc appears as Zinc Bisglycinate

Which active ingredients does Douglas Laboratories Vitamin D 1000 IU have?

  • Vitamin D appears as Cholecalciferol (D3)

Which categories do NOW Foods C-1000 Zinc & D-3 and Douglas Laboratories Vitamin D 1000 IU belong to?

  • Single Mineral
  • Single Vitamin

What health concerns do NOW Foods C-1000 Zinc & D-3 and Douglas Laboratories Vitamin D 1000 IU address?

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

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

  • NOW Foods C-1000 Zinc & D-3 has the highest total amount of Vitamin D: 2000 IU per serving

How do the serving sizes compare between the two supplements?

  • Serving size:
    • NOW Foods C-1000 Zinc & D-3: 1 capsule
    • Douglas Laboratories Vitamin D 1000 IU: 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 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
  • 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 D
    • This supplement has 1000 IU
    • Recommended Dietary Allowance in men: 600 IU
    • Recommended Dietary Allowance in women: 600 IU
    • Tolerable Upper Intake Level: 4000 IU

Last updated: February 15, 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.
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  • Author: VIOscan Research Team