Thorne Methyl-Guard Plus
vs
Doctor's Best Fully Active B12
Supplement Comparison

  • Vitamin B12 (Cobalamin): Thorne Methyl-Guard Plus 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
    • 7 nutrients compared
Bar chart: per-serving label amounts and listed forms for Thorne Methyl-Guard Plus vs Doctor's Best Fully Active B12.

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Frequently asked questions

Which active ingredients does Thorne Methyl-Guard Plus have?

  • Vitamin B2 (Riboflavin) appears as Riboflavin 5-Phosphate Sodium
  • Vitamin B6 (Pyridoxine) appears as Pyridoxal 5-Phosphate
  • Vitamin B9 (Folate) appears as L-5-Methyltetrahydrofolate
  • Vitamin B12 (Cobalamin) appears as Methylcobalamin

Which active ingredients does Doctor's Best Fully Active B12 have?

  • Vitamin B12 (Cobalamin) appears as Methylcobalamin

Which categories do Thorne Methyl-Guard Plus and Doctor's Best Fully Active B12 belong to?

  • Methylation Formula
  • Single Vitamin

What health concerns do Thorne Methyl-Guard Plus and Doctor's Best Fully Active B12 address?

  • Brain, Focus & Cognitive Function
  • Heart & Cardiovascular Health
  • Methylation Support
  • Mood Support
  • Energy & Metabolism
  • Neurological Support

Which product has a higher amount of Vitamin B12 (Cobalamin) per serving?

  • Thorne Methyl-Guard Plus has the highest total amount of Vitamin B12 (Cobalamin): 3000 mcg per serving

How do the serving sizes compare between the two supplements?

  • Serving size:
    • Thorne Methyl-Guard Plus: 3 capsules
    • Doctor's Best Fully Active B12: 1 capsule
  • Vitamin B2 (Riboflavin)
    • This supplement has 90 mg
    • Recommended Dietary Allowance in men: 1.3 mg
    • Recommended Dietary Allowance in women: 1.1 mg
    • Tolerable Upper Intake Level: Not established
  • Vitamin B6 (Pyridoxine)
    • This supplement has 45 mg
    • Recommended Dietary Allowance in men: 1.3 mg
    • Recommended Dietary Allowance in women: 1.3 mg
    • Tolerable Upper Intake Level: 100 mg
  • Vitamin B9 (Folate)
    • This supplement has 5 mcg DFE
    • Recommended Dietary Allowance in men: 400 mcg DFE
    • Recommended Dietary Allowance in women: 400 mcg DFE
    • Tolerable Upper Intake Level: 1000 mcg DFE
  • Vitamin B12 (Cobalamin)
    • This supplement has 3000 mcg
    • Recommended Dietary Allowance in men: 2.4 mcg
    • Recommended Dietary Allowance in women: 2.4 mcg
    • Tolerable Upper Intake Level: Not established
  • Vitamin B12 (Cobalamin)
    • This supplement has 1500 mcg
    • Recommended Dietary Allowance in men: 2.4 mcg
    • Recommended Dietary Allowance in women: 2.4 mcg
    • Tolerable Upper Intake Level: Not established

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