Doctor's Best Pure L-Arginine Powder
vs
Douglas Laboratories L-Arginine
Supplement Comparison

  • L-Arginine: Doctor's Best Pure L-Arginine Powder has 12× more
  • The image below shows:
    • Side-by-side charts with label nutrient amounts, per serving
    • Nutrient forms as listed on the label
    • 2 nutrients compared
Bar chart: per-serving label amounts and listed forms for Doctor's Best Pure L-Arginine Powder vs Douglas Laboratories L-Arginine.

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Frequently asked questions

Which active ingredients does Doctor's Best Pure L-Arginine Powder have?

  • L-Arginine appears as L-Arginine HCl

Which active ingredients does Douglas Laboratories L-Arginine have?

  • L-Arginine appears as L-Arginine Free Base

Which categories do Doctor's Best Pure L-Arginine Powder and Douglas Laboratories L-Arginine belong to?

  • Amino Acid Formula
  • Sports Formula

What health concerns do Doctor's Best Pure L-Arginine Powder and Douglas Laboratories L-Arginine address?

  • Athletic Performance
  • Heart & Cardiovascular Health
  • Recovery & Repair
  • Brain, Focus & Cognitive Function
  • Energy & Metabolism

How do the serving sizes compare between the two supplements?

  • Serving size:
    • Doctor's Best Pure L-Arginine Powder: 1 scoop
    • Douglas Laboratories L-Arginine: 1 capsule

Last updated: February 16, 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