Doctor's Best Vitamin D3 1000 IU
vs
21st Century One Daily Men's Health
Supplement Comparison

  • Vitamin D: same total amount on both labels
  • The image below shows:
    • Side-by-side charts with label nutrient amounts, per serving
    • Nutrient forms as listed on the label
    • 42 nutrients compared
Bar chart: per-serving label amounts and listed forms for Doctor's Best Vitamin D3 1000 IU vs 21st Century One Daily Men's Health.

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Frequently asked questions

Which active ingredients does Doctor's Best Vitamin D3 1000 IU have?

  • Vitamin D appears as Cholecalciferol (D3)

Which active ingredients does 21st Century One Daily Men's Health have?

  • Vitamin A appears as Retinyl Acetate and Beta-Carotene
  • Vitamin C appears as Ascorbic Acid
  • Vitamin D appears as Cholecalciferol (D3)
  • Vitamin E appears as dl-Alpha Tocopheryl Acetate
  • Vitamin K appears as Vitamin K1 Phytonadione
  • Vitamin B1 (Thiamin) appears as Thiamin Mononitrate
  • Vitamin B2 (Riboflavin) appears as Riboflavin
  • Vitamin B3 (Niacin) appears as Niacinamide
  • Vitamin B6 (Pyridoxine) appears as Pyridoxine HCl
  • Vitamin B9 (Folate) appears as Folic Acid
  • Vitamin B12 (Cobalamin) appears as Cyanocobalamin
  • Vitamin B7 (Biotin) appears as D-Biotin
  • Vitamin B5 (Pantothenic Acid) appears as D-Calcium Pantothenate
  • Calcium appears as Calcium Carbonate
  • Iodine appears as Potassium Iodide
  • Magnesium appears as Magnesium Oxide
  • Zinc appears as Zinc Oxide
  • Selenium appears as Sodium Selenate
  • Copper appears as Copper Oxide
  • Manganese appears as Manganese Sulfate
  • Chromium appears as Chromium Chloride
  • Lycopene

Which categories do Doctor's Best Vitamin D3 1000 IU and 21st Century One Daily Men's Health belong to?

  • Single Vitamin
  • Multivitamin

What health concerns do Doctor's Best Vitamin D3 1000 IU and 21st Century One Daily Men's Health address?

  • Brain, Focus & Cognitive Function
  • General Health
  • Heart & Cardiovascular Health
  • Immune System Support
  • Joint & Bone Health
  • Antioxidant Support
  • Energy & Metabolism
  • Men's Health

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

  • Both products list the same total amount of Vitamin D per serving

How do the serving sizes compare between the two supplements?

  • Serving size:
    • Doctor's Best Vitamin D3 1000 IU: 1 softgel
    • 21st Century One Daily Men's Health: 1 tablet
  • Vitamin D
    • This supplement has 1000 IU
    • Recommended Dietary Allowance in men: 600 IU
    • Recommended Dietary Allowance in women: 600 IU
    • Tolerable Upper Intake Level: 4000 IU
  • Vitamin A
    • This supplement has 900 mcg RAE
    • Recommended Dietary Allowance in men: 900 mcg RAE
    • Recommended Dietary Allowance in women: 700 mcg RAE
    • Tolerable Upper Intake Level: 3000 mcg RAE
  • Vitamin C
    • This supplement has 99 mg
    • Recommended Dietary Allowance in men: 90 mg
    • Recommended Dietary Allowance in women: 75 mg
    • Tolerable Upper Intake Level: 2000 mg
  • Vitamin D
    • This supplement has 1000 IU
    • Recommended Dietary Allowance in men: 600 IU
    • Recommended Dietary Allowance in women: 600 IU
    • Tolerable Upper Intake Level: 4000 IU
  • Vitamin E
    • This supplement has 15 mg
    • Recommended Dietary Allowance in men: 15 mg
    • Recommended Dietary Allowance in women: 15 mg
    • Tolerable Upper Intake Level: 1000 mg
  • Vitamin K
    • This supplement has 30 mcg
    • Adequate Intake in men: 120 mcg
    • Adequate Intake in women: 90 mcg
    • Tolerable Upper Intake Level: Not established
  • Vitamin B1 (Thiamin)
    • This supplement has 1.32 mg
    • Recommended Dietary Allowance in men: 1.2 mg
    • Recommended Dietary Allowance in women: 1.1 mg
    • Tolerable Upper Intake Level: Not established

Last updated: February 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