California Gold Nutrition Immune Complex 4
vs
Douglas Laboratories Natural C
Supplement Comparison

  • Vitamin C: Douglas Laboratories Natural C 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
    • 8 nutrients compared
Bar chart: per-serving label amounts and listed forms for California Gold Nutrition Immune Complex 4 vs Douglas Laboratories Natural C.

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Frequently asked questions

Which active ingredients does California Gold Nutrition Immune Complex 4 have?

  • Vitamin C appears as Ascorbic Acid
  • Vitamin D appears as Cholecalciferol (D3)
  • Zinc appears as Zinc Picolinate
  • Selenium appears as L-Selenomethionine

Which active ingredients does Douglas Laboratories Natural C have?

  • Vitamin C appears as Ascorbic Acid
  • Citrus Bioflavonoid Complex

Which categories do California Gold Nutrition Immune Complex 4 and Douglas Laboratories Natural C belong to?

  • Antioxidant Complex
  • Single Vitamin

What health concerns do California Gold Nutrition Immune Complex 4 and Douglas Laboratories Natural C address?

  • Antioxidant Support
  • General Health
  • Immune System Support
  • Respiratory Health

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

  • Douglas Laboratories Natural C has the highest total amount of Vitamin C: 1000 mg per serving

How do the serving sizes compare between the two supplements?

  • Serving size:
    • California Gold Nutrition Immune Complex 4: 1 capsule
    • Douglas Laboratories Natural C: 1 tablet
  • Vitamin C
    • This supplement has 500 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 1000 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 10 mg
    • Recommended Dietary Allowance in men: 11 mg
    • Recommended Dietary Allowance in women: 8 mg
    • Tolerable Upper Intake Level: 40 mg
  • Selenium
    • This supplement has 50 mcg
    • Recommended Dietary Allowance in men: 55 mcg
    • Recommended Dietary Allowance in women: 55 mcg
    • Tolerable Upper Intake Level: 400 mcg
  • 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

Last updated: February 20, 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