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Head to head · Vitamins & Minerals

NOW Foods Vitamin C-1000 Sustained Release vs Sports Research Vitamin D3 + K2 (5000 IU)

NOW Foods scores higher overall (8.1 vs 7.8 out of 10), mainly on value and transparency. Sports Research still leads on experience.

Updated September 2026 from our full reviews · How we score

Higher score
Front of NOW C-1000 Sustained Release 250-tablet bottle
NOW FoodsVitamin C-1000 Sustained Release
8.1
Good

1,000 mg of vitamin C with rose hips in a sustained-release tablet for about 6 cents a day; far more than most people need, but cheap and cleanly made.

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Front of Sports Research D3 + K2 60 veggie softgel bottle
Sports ResearchVitamin D3 + K2 (5000 IU)
7.8
Good

Amazon's top D3+K2 pick: vegan lichen D3 plus MK-7 K2 in coconut MCT oil; the 5,000 IU dose exceeds the adult upper limit for daily use.

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The short answer

Choose NOW Foods if…

  • People with low fruit and vegetable intake
  • Smokers and endurance athletes
  • Budget shoppers who want a large bottle
  • You care most about value, transparency

Choose Sports Research if…

  • Vegans who want lichen-derived D3
  • People with a documented deficiency under medical guidance
  • Anyone who wants D3 and K2 in one small softgel
  • You care most about experience

Side by side

Vitamin C-1000 Sustained ReleaseVitamin D3 + K2 (5000 IU)
Our score8.1 / 107.8 / 10
Efficacy (30%)7.47.4
Quality & Purity (25%)7.67.4
Value (20%)9.67.8
Experience (15%)7.88.8
Transparency (10%)8.88.3
FormTabletSoftgel
Serving1 tablet250 servings per container1 veggie softgel60 servings per container
Testing & certifications
cGMP facilityKosherHalal
Non-GMO Project VerifiedCertified VeganThird-party testedcGMP facility
DietaryVegan, Gluten-free, Soy-free, Dairy-free, Non-GMOVegan, Gluten-free, Soy-free, Non-GMO
Key ingredients
  • Vitamin C (as ascorbic acid)1,000 mg
  • Rose hips powder (Rosa canina, fruit)25 mg
  • Vitamin D3 (cholecalciferol from lichen, VegaDELight)125 mcg (5,000 IU)
  • Vitamin K2 (as menaquinone-7, from chickpea)100 mcg
  • Coconut MCT oil
Flavors——
Creator video reviews25

Pros and cons

Vitamin C-1000 Sustained Release

  • About $0.06 per day
  • 1,000 mg dose stays well under the 2,000 mg upper limit
  • Vegan, kosher and halal, made without major allergens
  • GMP-certified manufacturing
  • Far above daily needs, and absorption drops below 50% above 1 g
  • Large oval tablet with a noticeable vitamin smell
  • No evidence offered for the sustained-release design
  • No USP or NSF certification

Vitamin D3 + K2 (5000 IU)

  • Certified Vegan and Non-GMO Project Verified, with no soy, gelatin or carrageenan
  • D3 from lichen plus K2 as long-acting MK-7
  • Tiny, easy-to-swallow softgel in an MCT oil base
  • Official TikTok Shop listing rated 4.8 stars
  • 5,000 IU exceeds the 4,000 IU adult upper limit for daily use
  • No USP or NSF certification; testing claims are the brand's own
  • Evidence for K2's bone and arterial benefits is still limited
  • About $0.40 per day, more than plain D3

Our verdicts

Vitamin C-1000 Sustained Release

An inexpensive, well-made way to take 1,000 mg of vitamin C a day from a manufacturer with solid quality systems. Most people get enough vitamin C from food, so it suits heavy exercisers, smokers and people with low fruit and vegetable intake best; others can take it less often.

Full review

Vitamin D3 + K2 (5000 IU)

This is a well-made, vegan D3 and K2 combination that people clearly enjoy taking, which explains its bestseller status. The 5,000 IU dose is higher than most adults need day after day and exceeds the upper limit, so it fits best under a clinician's guidance or on a less-than-daily schedule; everyone else should consider the 2,500 IU version.

Full review

What creators say

Questions people ask

Is NOW Foods better than Sports Research?
In our scoring, NOW Foods Vitamin C-1000 Sustained Release rates higher overall (8.1 vs 7.8 out of 10). NOW Foods leads on value and transparency; Sports Research leads on experience. Scores weigh efficacy, quality, value, experience and transparency.
Who should choose NOW Foods over Sports Research?
Our reviews suggest NOW Foods is best for people with low fruit and vegetable intake, smokers and endurance athletes and budget shoppers who want a large bottle, while Sports Research is best for vegans who want lichen-derived D3, people with a documented deficiency under medical guidance and anyone who wants D3 and K2 in one small softgel.

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