What Can Vitamin K2 Do for You?

The early 20th century was the Golden Age of vitamin research. Scientists identified previously unknown compounds and named them in order: vitamins A, B, C and so on. The B vitamins turned out to be a family: vitamin B1, vitamin B2, vitamin B3, for example, all the way through vitamin B12. A Danish scientist, Henrik Dam, identified a fat-soluble compound critical for blood clotting in 1929. The German journal that published his research termed the discovery Koagulationsvitamin, aka vitamin K. Most people are unaware that in addition to vitamin K1, which controls clotting, scientists are also studying vitamin K2 and vitamin K3. What does vitamin K2 do?

Will Vitamin K2 Do Anything for Your Health?

Q. I became interested in vitamin K2 about a year ago when my nurse practitioner told me to take it for my joints. Curious, I started researching it to see what it could do. And boy, what it can do! I take it every day now for general overall health and my joints.

I found two clinical trials on vitamin K2 with very encouraging results. Vitamin K2 supplementation increased bone density in older women in one trial (Osteoporosis International, July 2007). In another trial it reduced stiffness in women’s arteries (Thrombosis and Haemostasis, May 2015). Granted, women took supplements daily for three years to achieve these effects, but they are impressive results nonetheless.

What Does the Research Show?

A. Thank you for highlighting research on this compound. A review of the medical literature on vitamin K2 (menaquinone) suggests that it may play an important role in getting calcium into bones and keeping it out of arteries (Frontiers in Cardiovascular Medicine, Feb. 5, 2019).  That could help explain both benefits you describe. Fermented foods such as cheeses or natto provide vitamin K2 in the diet.

Danish investigators are currently conducting a trial of menaquinone-7 supplements to see if they can alleviate aortic valve calcification (BMJ Open, Aug. 23, 2018). That would certainly be a significant health benefit. However, another recent study found that such supplements might actually increase calcification of blood vessels (American Journal of Clinical Nutrition, online Aug. 6, 2019).  The researchers didn’t report any adverse effects, but it seems we still need more clinical trials to understand what this compound can and cannot do.

Can Vitamin K2 Improve Your Bone Health?

Q. Please discuss vitamin K2. This medication has been shown to direct calcium from your diet to your bones. My bone scan improved after I started taking vitamin D3 with K2. The rheumatologist said she never saw such an improvement.

A. Although we often refer to vitamin K as if it were just one compound, in fact it is a cluster of natural chemicals that our bodies need (Food Science & Nutrition, June 17, 2025).  Vitamin K1 is also called phylloquinone. It is best known for its ability to promote blood clotting. Plants, particularly green leafy vegetables and vegetable oils, are the best dietary sources of vitamin K1.

Vitamin K2 is a term for several menaquinone compounds that play important roles in calcium metabolism and inflammation. The best dietary sources are eggs, dairy products and meats. Fermented foods such as natto or cheese are also rich sources.

Vitamin K2 works together with the vitamin-K-dependent protein osteocalcin to manage the movement of calcium into and out of bone. Vitamin K supplementation seems to result in more elastic blood vessels and less arterial calcification. It may also lower the risk of developing type 2 diabetes because of its anti-inflammatory activity.

Vitamin K may also be important for maintaining muscle mass as well as bone strength. The supplement usually used in such studies is a form of vitamin K2, MK-7. Experts do not all agree on the value of such supplementation for bone density. However, other researchers have concluded that an adequate supply of vitamin K along with optimal vitamin D status could help maintain bone health (Nutrients, July 25, 2024).