Swanson Certified Organic Spirulina
vs
Douglas Laboratories Seleno-Methionine
Supplement Comparison

  • Selenium: Douglas Laboratories Seleno-Methionine has 160× more
  • The image below shows:
    • Side-by-side charts with label nutrient amounts, per serving
    • Nutrient forms as listed on the label
    • 7 nutrients compared
Bar chart: per-serving label amounts and listed forms for Swanson Certified Organic Spirulina vs Douglas Laboratories Seleno-Methionine.

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Frequently asked questions

Which active ingredients does Swanson Certified Organic Spirulina have?

  • Iron
  • Magnesium
  • Selenium
  • Chromium
  • Spirulina (Arthrospira platensis) Microalgae appears as Parry's Organic Spirulina

Which active ingredients does Douglas Laboratories Seleno-Methionine have?

  • Selenium appears as L-Selenomethionine

Which categories do Swanson Certified Organic Spirulina and Douglas Laboratories Seleno-Methionine belong to?

  • Algae
  • Single Mineral

What health concerns do Swanson Certified Organic Spirulina and Douglas Laboratories Seleno-Methionine address?

  • Antioxidant Support
  • Immune System Support
  • Liver & Detox Support
  • General Health

Which product has a higher amount of Selenium per serving?

  • Douglas Laboratories Seleno-Methionine has the highest total amount of Selenium: 200 mcg per serving

How do the serving sizes compare between the two supplements?

  • Serving size:
    • Swanson Certified Organic Spirulina: 2 tablets
    • Douglas Laboratories Seleno-Methionine: 1 capsule
  • Iron
    • This supplement has 0.7 mg
    • Recommended Dietary Allowance in men: 8 mg
    • Recommended Dietary Allowance in women: 18 mg
    • Tolerable Upper Intake Level: 45 mg
  • Selenium
    • This supplement has 1.25 mcg
    • Recommended Dietary Allowance in men: 55 mcg
    • Recommended Dietary Allowance in women: 55 mcg
    • Tolerable Upper Intake Level: 400 mcg
  • Chromium
    • This supplement has 3.5 mcg
    • Adequate Intake in men: 35 mcg
    • Adequate Intake in women: 25 mcg
    • Tolerable Upper Intake Level: Not established
  • Selenium
    • This supplement has 200 mcg
    • Recommended Dietary Allowance in men: 55 mcg
    • Recommended Dietary Allowance in women: 55 mcg
    • Tolerable Upper Intake Level: 400 mcg

Last updated: February 19, 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