Life Extension Vitamin D3 with Sea-Iodine
vs
Natural Factors RxOmega-3 Ultra Strength with Vitamin D3
Supplement Comparison

  • Vitamin D: Life Extension Vitamin D3 with Sea-Iodine has 5.0× 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 Life Extension Vitamin D3 with Sea-Iodine vs Natural Factors RxOmega-3 Ultra Strength with Vitamin D3.

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Frequently asked questions

Which active ingredients does Life Extension Vitamin D3 with Sea-Iodine have?

  • Vitamin D appears as Cholecalciferol (D3)
  • Iodine appears as Potassium Iodide

Which active ingredients does Natural Factors RxOmega-3 Ultra Strength with Vitamin D3 have?

  • Vitamin D appears as Cholecalciferol (D3)
  • Eicosapentaenoic Acid (EPA) appears as Unspecified
  • Docosahexaenoic Acid (DHA) appears as Unspecified

Which categories do Life Extension Vitamin D3 with Sea-Iodine and Natural Factors RxOmega-3 Ultra Strength with Vitamin D3 belong to?

  • Single Mineral
  • Single Vitamin
  • Fish Oil and Omega-3

What health concerns do Life Extension Vitamin D3 with Sea-Iodine and Natural Factors RxOmega-3 Ultra Strength with Vitamin D3 address?

  • Thyroid Support
  • Brain, Focus & Cognitive Function
  • General Health
  • Heart & Cardiovascular Health
  • Immune System Support
  • Joint & Bone Health
  • Anti-Inflammatory Support
  • Eye Health

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

  • Life Extension Vitamin D3 with Sea-Iodine has the highest total amount of Vitamin D: 5000 IU per serving

How do the serving sizes compare between the two supplements?

  • Serving size:
    • Life Extension Vitamin D3 with Sea-Iodine: 1 capsule
    • Natural Factors RxOmega-3 Ultra Strength with Vitamin D3: 2 softgels
  • Vitamin D
    • This supplement has 5000 IU
    • Recommended Dietary Allowance in men: 600 IU
    • Recommended Dietary Allowance in women: 600 IU
    • Tolerable Upper Intake Level: 4000 IU
  • Iodine
    • This supplement has 1000 mcg
    • Recommended Dietary Allowance in men: 150 mcg
    • Recommended Dietary Allowance in women: 150 mcg
    • Tolerable Upper Intake Level: 1100 mcg
  • 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 12, 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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  • See an error? Report it through our Contact page.
  • Author: VIOscan Research Team