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  • What is vitamin K?

    Vitamin K helps with proper blood clotting as well as with calcium utilization in bones and the cardiovascular system (see What It Does).
  • Do you need to take vitamin K as a supplement?

    Most people are not deficient in vitamin K and symptomatic deficiency is rare, so unless you have a malabsorption condition or are severely malnourished, you likely get sufficient vitamin K from your diet (e.g., from green leafy vegetables, dairy, and fermented foods (see how to get vitamin K from food). Higher intakes of certain forms of vitamin K2 from food have been associated with a reduced risk of coronary artery calcification and mortality from coronary heart disease. Vitamin K supplements, typically at high doses, have been clinically evaluated to see if they increase bone density, reduce fractures, or reduce coronary artery calcification and improve cardiovascular function, but results have been mixed, so it is not clear that supplementation will help (see What It Does).
  • Which form of vitamin K is best?

    There are several forms of vitamin K. All are active, but one, the MK-7 form of vitamin K2, can increase blood levels of vitamin K up to 8 times as much as other forms (see What It Is and What to Consider When Buying).
  • What did CL's tests of vitamin K supplements find?

    Among the vitamin K supplements selected for testing, two failed our tests because they each contained much less vitamin K than listed (see What CL Found).
  • Which vitamin K supplement is best?

    Among the vitamin K supplements that CL tested and Approved for Quality (see What CL Found), CL selected Top Picks, based quality, dosage, and price, for vitamin K1 as well the MK-4 and MK-7 forms of vitamin K2. CL also selected Top Picks for supplements combining vitamin K with calcium, vitamin D, magnesium, and/or boron.
  • How much vitamin K should I take?

    For adults, adequate daily intake of vitamin K is 90 mcg for women and 120 mcg for men. It is difficult to know what dose may be most useful in bone health (or if any dose is truly beneficial). However, studies involving supplements containing K1 or the MK-4 form of K2 tend to use very high doses (e.g., 500 mcg to 45,000 mcg), while studies with the MK-7 form of K2 have used more moderate doses, e.g., 180 mcg (see What to Consider When Using)
  • How to take vitamin K:

    Vitamin K is fat soluble, so you'll absorb more of it when you take it with a meal that has fats or oils. However, because other fat-soluble vitamins, such as vitamin D, can compete with vitamin K for absorption, it's best to take vitamin K at least 3 hours apart from vitamin D (see What to Consider When Using). [Note: Many bone health supplements contain vitamins K and D together, but there is no need for this. Also, vitamin K does not lower the risks associated with taking high-dose vitamin D or prevent vitamin D overdose.]
  • Vitamin K safety and side effects:

    Vitamin K is fairly safe. However, it can interact with certain medications, including blood-thinning drugs. If you have an allergy to soy, be aware that most MK-7 forms of vitamin K are derived from soy — although one brand is derived from chickpeas (see Concerns and Cautions).

Make sure you're choosing the best vitamin K supplements approved in our tests!

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Alphabetical list of vitamin K supplements compared in this review

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Bluebonnet Vitamin K1 100 mcg

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Bronson Vitamin K2

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Flora Bone Health+ with Calcium, Magnesium, and Vitamin D & K

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Garden of Life Vitamin Code RAW K-Complex

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GNC Vitamin K

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Healthy Origins Vitamin K2 as MK-7

View Larger Image 7743_large_InnovixLabs-VitaminK-BoneHealth-2022.png

InnovixLabs Full Spectrum Vitamin K2

View Larger Image 7809_large_JarrowFormulas-BoneHealth-2022.png

Jarrow Formulas BoneUp

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Life Extension Bone Restore with Vitamin K2

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Naturelo Bone Strength Plant Calcium Complex With Magnesium, C, D3, K2, & Zinc

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New Chapter Bone Strength Take Care

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NOW Vitamin D-3 & K-2

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NuBest NuBest Tall 10+

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Sports Research Plant-Based D3 + K2 2-in-1 Formula

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Thorne 3-K Complete

You must be a member to get the full test results along with recommendations and quality ratings. You will get results for 11 vitamin K supplements selected by and four others that passed testing in its voluntary Quality Certification Program.
In this comprehensive review, you'll discover:
  • Which vitamin K supplements failed our tests and which ones passed -- -- including combinations with calcium, magnesium,vitamin D & vitamin K
  •'s Top Picks among vitamin K supplements
  • How to choose a vitamin K supplement that best suits your needs
  • The difference in potency among the popular forms of vitamin K: vitamin K1 and two forms of vitamin K2  -- menaquinone-4 (MK-4) and menaquinone-7 (MK-7)
  • The dose of vitamin K used for specific applications and how to best take it for maximum absorption
  • How to get vitamin K from foods
  • Potential drug interactions and side effects of vitamin K, including interactions with certain anticoagulants and soy allergy  

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Additional Information
Tested through CL's Quality Certification Program prior to, or after initial posting of this Product Review.