Thorne Quercetin Complex
vs
Douglas Laboratories Glucosamine + MSM Forte
Supplement Comparison

  • Bromelain: Thorne Quercetin Complex has 10× more
  • The image below shows:
    • Side-by-side charts with label nutrient amounts, per serving
    • Nutrient forms as listed on the label
    • 12 nutrients compared
Bar chart: per-serving label amounts and listed forms for Thorne Quercetin Complex vs Douglas Laboratories Glucosamine + MSM Forte.

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Frequently asked questions

Which active ingredients does Thorne Quercetin Complex have?

  • Quercetin appears as Quercetin Phytosome
  • Bromelain

Which active ingredients does Douglas Laboratories Glucosamine + MSM Forte have?

  • Vitamin C appears as Ascorbic Acid
  • Methylsulfonylmethane (MSM) appears as OptiMSM Methylsulfonylmethane (MSM)
  • Glucosamine Sulfate appears as Glucosamine Sulfate 2KCl (from crab and shrimp)
  • Bromelain appears as Bromelain (Ananas comosus stem)
  • Grape (Vitis vinifera) Seed Extract appears as Grape Seed Extract (containing proanthocyanidins)

Which categories do Thorne Quercetin Complex and Douglas Laboratories Glucosamine + MSM Forte belong to?

  • Antioxidant Complex
  • Joint Formula

What health concerns do Thorne Quercetin Complex and Douglas Laboratories Glucosamine + MSM Forte address?

  • Antioxidant Support
  • Anti-Inflammatory Support
  • Immune System Support
  • Respiratory Health
  • Joint & Bone Health
  • Recovery & Repair

How do the serving sizes compare between the two supplements?

  • Serving size:
    • Thorne Quercetin Complex: 1 capsule
    • Douglas Laboratories Glucosamine + MSM Forte: 1 capsule
  • Vitamin C
    • This supplement has 50 mg
    • Recommended Dietary Allowance in men: 90 mg
    • Recommended Dietary Allowance in women: 75 mg
    • Tolerable Upper Intake Level: 2000 mg

Last updated: February 11, 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