If you care about your bones, kidneys, and long-term health, vitamin K2 is one nutrient you don’t want to miss.
Many Americans are not getting enough. In fact, studies show that up to 97% of older adults may be low in vitamin K2, even though it plays a key role in keeping bones strong and kidneys healthy. And the official guidelines don’t even include a daily value for K2 yet.
Let’s break it down so it’s easy to understand.
The Types of Vitamin K
There are two main forms of vitamin K:
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K1 (phylloquinone) – This comes from dark green leafy vegetables like spinach and kale. It helps your blood clot, so you stop bleeding after a cut. Deficiency sometimes causes brain hemorrhages, with devastating consequences.
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K2 (menaquinone) – This is the newly recognized form of vitamin K that scientists are still learning more about. It comes in two main types: MK-4 and MK-7. These help put calcium where it belongs: in your bones. Deficiency may promote kidney stones and osteoporosis.
We’ve known about K1 for a long time. But K2 is finally getting the attention it deserves — and for good reason.
What Makes K2 So Special?
Vitamin K2 helps move calcium to the right places in your body.
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It puts calcium into your bones and teeth, where you want it.
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It keeps calcium from ending up in places where it doesn’t belong.
This suggests K2 may help reduce the risk of osteoporosis and kidney stones.
Vitamin K2 also plays a role in supporting the health of many other cells in your body, including muscle cells, bone marrow cells, and cells lining your arteries.
How K2 Helps Your Body Use Calcium the Right Way
One of the most important things vitamin K2 does is help your body use calcium properly.
Here’s how it works:
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K2 turns on special proteins in your body, including osteocalcin and matrix Gla-protein (MGP).
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These proteins grab onto some of the calcium that’s always in your blood.
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The calcium is then sent to the right places — into bones and teeth, and away from places it shouldn’t go.
This process keeps your bones strong and helps protect your heart and blood vessels. It’s not just about stopping calcium buildup — it’s about ensuring the calcium in your diet goes to the right places.
“When carboxylated [by vitamin k2], these proteins appear to have the ability to chelate and import calcium from the blood to the bone, thereby reducing the risk of osteoporosis.”
— Nutrients, 2024 (source)
MK-4 vs. MK-7: What’s the Difference?
MK-4 and MK-7 are two different forms of vitamin K2.
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MK-4 is found in small amounts in meat, butter, and eggs. It works quickly but doesn’t stay in the body long.
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MK-7 is found in fermented foods like natto (a Japanese food made from soybeans). It stays in your system longer, so it may offer more lasting benefits.
I recommend getting both MK-4 and MK-7. That way, you cover all your bases.
The Supplement I Take
I personally take a supplement called Carlson K Complete, which includes:
When I first went looking for a high-quality vitamin K2 supplement to take myself, I specifically wanted one made through natural fermentation, not synthetic production. Carlson K Complete came up in my search, and it looked promising.
I noticed it was significantly more expensive — nearly three times the cost of many other K2 supplements. That made me hopeful it was naturally fermented. But the product label and website didn’t explain how it was made, so I reached out to the company directly.
A representative from their technical division confirmed that their K2 is produced using a natural fermentation process with chickpea protein and Bacillus licheniformis — a friendly bacteria. This multi-step process involves purification and crystallization to ensure a high-purity, all-trans MK-7, which is the form your body actually uses.
They call their MK-7 MenaQ7®. They say it’s is over 96% pure and apparently it’s been tested by independent labs for quality and potency.
You can learn more about MenaQ7 here: menaq7.com
Why Most People Don’t Get Enough
Most people don’t eat natto, and they don’t get much MK-4 from food either — unless they eat a lot of grass-fed animal products. That’s why supplementing with vitamin K2 is a smart idea for most adults, especially older adults or anyone concerned about bone loss, heart disease, or calcium supplements.
And doctors are way behind the 8 ball on this subject — not because they don’t care, but because the official guidelines are outdated and incomplete. There is currently no RDA (recommended daily allowance) for vitamin K2, and many experts believe the existing RDA for vitamin K1 is set far too low to support full-body vitamin K needs, especially when it comes to bone health.
Does K2 Also Help Your Heart?
I’ve seen K2 described as important for heart health, too, since low vitamin K2 may be associated with calcifications in the arteries. However, that idea does not make sense to me.
That argument assumes that if K2 helps reduce calcium buildup in arteries, it must prevent heart disease. But that’s based on a flawed model. The real problem isn’t the calcium — it’s the damage that happens first.
You see, calcium does not harm our arteries. In fact, calcium appears to play an important role in helping arteries that have been damaged by inflammatory fat. If you have had a scan that showed calcium in your arteries, that doesn’t mean you need to remove the calcium. It’s simply a marker — a sign that oxidative stress has already damaged the artery walls. The calcium shows up later, to help strengthen the area weakened by inflammation. The calcium is almost like a patch, in that sense. So while K2 may help reduce calcium buildup, that doesn’t mean it’s preventing the actual root cause of heart disease.
According to Google’s medical summary:
“While vitamin K2 is theorized to play a role in inhibiting arterial calcification, research on its direct effect on lowering existing coronary artery calcium (CAC) scores is mixed.”
If you want to understand what really causes artery damage — and how to protect your cardiovascular health — I explain it all in my 3-part series: What the American Heart Association Is Hiding From You
Other Supplements I Recommend
My approach to supplementation is this: We should supplement with nutrients that we don’t easily get in our diet. Most of the supplements lining the shelves in your typical health food store are not nutrients and have little to no chance of helping you. According to some reports, thousands of supplements tested contain illegal drugs, viagra, mold, hormones, caffeine, and many other undisclosed ingredients.
Final Thoughts
If you want strong bones, a healthy heart, and better calcium balance, consider adding a vitamin K2 supplement to your routine — especially one that gives you both MK-4 and MK-7, like Carlson K Complete.
I recommend choosing a brand that uses natural, biologically active ingredients — even if it costs a little more. Your health is worth it.
Sources:
A shame that natto isn’t more widely available in the West as it not only provides enough K2 to heal the body but it also provides the serine protease enzyme Nattokinase. I suspect that this national dish is one of the reasons why so many Japanese citizens live past 100 years old.
Unfortunately, I don’t think human health is very high-up on politicians’ agendas. Politicians want us to work and die before we collect our pensions. I’ve seen the tragedy in care homes where the elderly are fed junk food and left in front of the TV. They die premature deaths. It is a mass avoidable tragedy.
Health is about more than nutrients. It is the collective love of humanity to be well, but this is overshadowed by capitalist objectives. What is the solution?
A wise older gentleman told me what we have now is crony capitalism. What we need is conscious capitalism. But I think we also need a new collective mythology that meets the needs of our times.
Already supplementing with the other items you recommend including CB Supplements (for years now), just added a subscription for this product. 76 in five weeks, bone health and strength is critically important for seniors – as I know all too well what happens when one of us breaks a hip. So happy to see a strong recommendation from you on this. Have all your books, follow as much as I can your recommendations. Thanks for being one of the few medical professionals in this country who actually understands proper nutrition.
Thank you so much for this! We recently looked into Vitamin K and were considering adding a supplement, but before making a decision, we checked your site to see if it was one of your recommendations. Since it wasn’t listed at the time, we decided to hold off. Now that you’ve shared this, we’ll go grab it! We really value your wisdom and are so grateful for the work you’re doing—thank you for being a trusted resource!
I see that Carlson k complete has 500mcg k1, 1.5mg mk4, and 45mcg mk7.
How many a day would you recommend?
Another perspective https://www.takebackyrhealth.com/post/how-grass-finished-beef-reduces-heart-disease-risk
What amount of K2 do you recommend? I always thought to stay away from too much K as it is one of the fat soluble vitamins.
Mine too is NOW brand as Menaquinone-7MK7 from chickpea? 100mcg Is this one ok please Dr Cate? Thanks
I noticed the Carlson Complete has 25 mcg MK-7. I currently have a Mk-7 supplement, Now brand, that has 100 mcg. I have no idea how the Now supplement is processed. Im going to get the Carlson complete. I’m thinking I could take both or ditch the one I currently have. Any thoughts?
You mention that vitamin K2 appears in fermented products. I’ve recently become interested in home fermentation, particularly in making sauerkraut and pickles. Would truly fermented vegetables (not store-bought) also have vitamin K2 in significant amounts?
That’s what I hoped. Turns out, only certain strains of bacteria can make the forms of K2 we need, unfortunately.
Nice article, but where is Carlson K Complete available in Canada? I assume Trump has not applied tariffs to it yet! Lol
If I find some available here, I will let you know.
If you’ve got Amazon up there, I found Carlson K Complete there.