Douglas Laboratories K2-D3 with Astaxanthin
vs
Protocol For Life Vitamin D3 5000 IU
Supplement Comparison

  • Vitamin D: Protocol For Life Vitamin D3 5000 IU 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 Douglas Laboratories K2-D3 with Astaxanthin vs Protocol For Life Vitamin D3 5000 IU.

Frequently asked questions

Which active ingredients does Douglas Laboratories K2-D3 with Astaxanthin have?

  • Vitamin D appears as Cholecalciferol (D3)
  • Vitamin K appears as Vitamin K2 trans MK-7 K2VITAL
  • Astaxanthin appears as AstaReal Astaxanthin (supercritical CO2 extract of Haematococcus pluvialis)

Which active ingredients does Protocol For Life Vitamin D3 5000 IU have?

  • Vitamin D appears as Cholecalciferol (D3)

Which categories do Douglas Laboratories K2-D3 with Astaxanthin and Protocol For Life Vitamin D3 5000 IU belong to?

  • Single Vitamin

What health concerns do Douglas Laboratories K2-D3 with Astaxanthin and Protocol For Life Vitamin D3 5000 IU address?

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

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

  • Protocol For Life Vitamin D3 5000 IU has the highest total amount of Vitamin D: 5000 IU per serving

How do the serving sizes compare between the two supplements?

  • Serving size:
    • Douglas Laboratories K2-D3 with Astaxanthin: 1 capsule
    • Protocol For Life Vitamin D3 5000 IU: 1 softgel
  • Vitamin D
    • This supplement has 2500 IU
    • Recommended Dietary Allowance in men: 600 IU
    • Recommended Dietary Allowance in women: 600 IU
    • Tolerable Upper Intake Level: 4000 IU
  • Vitamin K
    • This supplement has 180 mcg
    • Adequate Intake in men: 120 mcg
    • Adequate Intake in women: 90 mcg
    • Tolerable Upper Intake Level: Not established
  • 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

Last updated: January 3, 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