Is there any evidence for vitamin K2 supplementation?

What the evidence says

Vitamin K2 is a nutrient your body uses to activate proteins involved in bone building and in keeping calcium out of blood vessel walls. Supplement companies market it for stronger bones and healthier arteries, so it is worth looking at what studies actually show.

For bone health, several combined analyses of randomized trials found that vitamin K2 supplements improve blood markers that reflect how bone tissue is being built and broken down. Some of these analyses also found a small improvement in lower spine bone density and possibly fewer fractures in postmenopausal women, though the improvements were modest and researchers say longer studies are still needed to be fully confident.

For heart and blood vessel health, the picture is less clear. One meta-analysis of randomized trials found that vitamin K supplements slowed the buildup of calcium in heart arteries. But more recent, well-designed trials in people with kidney disease and in people with type 2 diabetes and heart disease found no meaningful improvement in artery stiffness or calcium buildup after 6 to 18 months of vitamin K2. This mismatch between older and newer results is why the evidence is called mixed rather than strong.

For other uses sometimes claimed for vitamin K2, such as diabetes, arthritis, kidney stones, or cancer, a review of the research found the evidence too limited to draw conclusions.

In Canada, vitamin K2 supplements are sold as regulated natural health products, meaning they must follow approved dosing and safety standards before being licensed for sale. This differs from prescription-only vitamin K, which is used at much higher, medical doses for specific conditions like reversing blood thinners.