Vitamin K2 can help strengthen your bones and improve your cardiovascular health.
Given the prevalence of osteoporosis and heart disease, that’s a goal just about everyone should strive for.
Several different molecules belong to the family of compounds known as Vitamin K2, and all of them play a critical role in how your body regulates blood clotting, blood vessel structure, and bone health.
Our research team has analyzed the vitamin K2 supplements on the market to determine which are the most potent and most effective—here are our rankings.
1. Sports Research Natural MK-7 Vitamin K2
Sports Research makes a high-quality vitamin K2 supplement that uses the proprietary chickpea extract MK-7 as its source for the vitamin.
Each capsule contains 100 micrograms of vitamin K2, and the capsules are made of vegetarian-friendly glycerine.
To top it off, the vitamin K2 is dissolved in extra virgin organic olive oil, which helps substantially with absorption. All of these perks make it one of the best K2 supplements out there.
2. Zhou Nutrition K2 + D3
If you want to improve your heart health and bone health at the same time, Zhou Nutrition’s K2 + D3 is an excellent choice.
It combines 90 micrograms of vitamin K2 with 5000 IUs of vitamin D3, a critical vitamin for (you guessed it) heart and bone health that many people are chronically lacking, especially in the winter. With no extraneous ingredients and third-party testing for purity and dosage, you can’t go wrong with Zhou K2 + D3.
3. MaryRuth’s Organics Vitamin K2
MaryRuth’s Organics delivers its vitamin K2 supplement in liquid form, dissolved in organic olive oil.
This means the supplement is extremely pure and extremely well absorbed, because the fat-soluble vitamin K2 is ingested in a dissolved format already.
The liquid format means it’s easy to mix into shakes, smoothies, and drinks. Minimalists will love this supplement too, as its sole ingredients are vitamin K2, organic olive oil, and water.
4. InnovixLabs Full Spectrum Vitamin K2
InnovixLabs walks the line between the standard dosage vitamin K2 supplements and those that offer megadose-range amounts of vitamin K2.
It provides 500 micrograms of vitamin K2 in the MK-4 form as well as an additional 100 micrograms in the MK-7 form, so it might be more biologically active than single-form vitamin K supplements.
These are dissolved in a mix of olive oil and MCT oil, so it’s bound to be absorbed well, too.
5. Life Extension Super K
Life Extension Super K is the go-to supplement for people who want a megadose of all three K vitamins.
While K2 has specific uses in arterial and bone health, vitamins K1 and K3 may play a role in health as well. Unlike other vitamin K2 supplements, Life Extensions Super K doesn’t stick to standard dosages–one capsule contains 2600 micrograms of the K vitamins, of which 1000 is vitamin K2.
Most people would be better suited with a standard dosage, but if you know you want a high dose, Life Extension should be your choice.
6. Jarrow Formulas MK-7
Jarrow Formulas delivers 90 micrograms of vitamin K2 in a gelatin-based softgel. The vitamin is dissolved in a mix of medium chain triglycerides and soybean oil, so absorption is likely to be good.
That aside, it’s a pretty standard vitamin K2 supplement, neither standing out or failing on any other front.
7. Solgar Vitamin K2
Solgar Vitamin K2 is a straightforward, simple vitamin K2 supplement with 100 micrograms of vitamin K2 per capsule. The capsule are vegetarian friendly, and delivers a small amount of calcium as well.
Aside from silica as a binder and filler, the supplement design is fairly clean, though not the best.
8. Now MK-7 K2
Now Foods has a vitamin K2 supplement that uses the popular MK-7 extract from chickpeas as its source of the active ingredient, but unfortunately the quality of the rest of the supplement is subpar.
It has a few fillers that the best vitamin K2 supplements don’t have, and it doesn’t deliver the supplement alongside any synergistic vitamins or in a format that’s rapidly absorbed.
9. Nature Made K2
Nature Made is about as basic as you can get in a vitamin K2 supplement. It delivers 100 micrograms of vitamin K2, but it doesn’t use as clean of a supplement design as many of its competitors.
It uses soybean oil to dissolve the vitamin K2, instead of the healthier but more expensive olive oil or coconut oil used by other supplements, and purists will not like the use of artificial coloring agents either.
10. Doctor’s Best Natural Vitamin K2
While it’s a fairly popular vitamin K2 supplement, Doctor’s Best Natural Vitamin K2 gets outclassed by its competitors on several fronts.
Its dosage is half that of most other vitamin K2 supplements, and its ingredients list is bloated with stabilizers, preservatives, and binders that aren’t necessary. It doesn’t deliver its vitamin K2 in a fat-based solvent, so absorption isn’t expected to be great either.
Who should buy vitamin K2?
Vitamin K2 is one form of vitamin K, a relatively recently discovered vitamin that contributes to bone strength, blood clotting, and cardiovascular health. While the majority of people get enough vitamin K2 in their diet, about one-third of people eat a diet that’s deficient in vitamin K2.
The best way to ensure you hit adequate K2 intake is to make sure you eat foods like kale, broccoli, soybeans, and collard greens. However, that may not be realistic for everyone: if it’s not, a K2 supplement is the next best thing.
People who are specifically concerned about their bone health may also want to take a vitamin K2 supplement, since several clinical trials have found that vitamin K supplementation can increase bone density in the lumbar spine (1).
Vitamin K2 could also be useful for improving cardiovascular health, as many of the proteins that rely on vitamin K are associated with reducing the buildup of plaque inside your arteries. Beyond bone health and heart health, there are a few special groups who are particularly prone to vitamin K2 deficiency.
These groups include people with celiac disease and people who have had gastric bypass surgery or other weight loss surgeries. These conditions affect your ability to absorb vitamin K, which puts you at risk for deficiency in the long run.
How we ranked
For our rankings of the top vitamin K2 supplements, our primary criteria were the dose of vitamin K2 supplied per serving, and the method of delivery.
Dosage is pretty much self-explanatory: we were looking for supplements that provided enough vitamin K2 to take even a poor quality diet up into the range of adequate dietary intake of vitamin K2, according to the updated 2020 dietary guidelines.
That meant restricting our field to products that provided at least 90 micrograms (mcg) per capsule of vitamin K2. We did not have any preference for the MK-4 or MK-7 version of vitamin K2, because the scientific research is unclear on whether either of these is better than the other.
Beyond just the dose, we also looked at how the supplemental vitamin K2 was delivered. Unlike many common vitamins, such as vitamin C, vitamin K2 is fat soluble, not water soluble. This means that K2 is more effectively delivered in supplemental form when it is paired with or dissolved in an oil or fat.
That’s why we rated vitamin K2 supplements higher if they used a high quality oil like olive oil or MCT oil to deliver vitamin K2, and rated supplements lower if they used a lower quality oil like a generic vegetable oil.
These supplements, in turn, were rated higher than supplements that used no fat-based solvent: these types of vitamin K2 supplements either ended up at the bottom of our rankings, or were eliminated completely.
After evaluating the dose and the quality of the solvent used to deliver it, we also considered the purity of the overall supplement design. Unnecessary binders, fillers, coloring agents, or (for liquid supplements) flavoring agents all detracted from the overall score—these compounds don’t make the supplement more effective.
In most cases, we found capsules (ideally vegetable-based cellulose capsules) to be more versatile than liquid based vitamin K2 supplements, but we did make an exception for MaryRuth’s Organic K2 liquid.
Having the option to add vitamin K2 to a smoothie or shake, or to take it by mouth using the dropper, can be nice for people who don’t like or have difficulties taking capsules.
We also made sure to include at least one product that combined vitamin D3 with K2, as this combination has been very successful at increasing bone density in older women.
Finally, we ranked the remaining products based on dose, delivery, purity, and format. Our team feels that these are the best options available right now if you are looking for a vitamin K2 supplement.
Vitamin K2 is essential for blood coagulation and plays a vital role in other aspects of creating good health. If you’ve never heard of it, you’re not alone; vitamin K2 gets little attention in the Western world despite its importance in optimal physical function.
Originally reported by a German scientific publication in 1929 as a key component in the blood clotting process, Koagulationsvitamin came to be known as vitamin K2. (2)
Weston Price, a legendary dentist of the same era who gathered data around the world focused on links between diet and disease, is believed to have discovered vitamin K2 as well. He didn’t know what it was, referring to it as Activator X, and noting in his journals this mystery nutrient appeared to prevent tooth decay and chronic disease in populations who ate non-industrial diets. (3)
Modern science designates the two types of vitamin K as K1 and K2: vitamin K1 is phylloquinone, and is found in leafy green plant foods (and many green drinks); vitamin K2 is menaquinone, occurring in fermented foods and animal products. (4)
Just like all the components of an engine are necessary in order to start the vehicle and drive off, everything in the body is designed to interact and perform various segments of the required processes for running the physical engine.
Vitamin K modifies proteins to facilitate the binding of calcium, an essential mineral for strong bones and good teeth, as well as other bodily functions. (5)
K1 is utilized by the liver in activating the calcium-binding properties of protein that clot blood; K2 activates the proteins in charge of regulating the distribution of calcium throughout the body. (6)
Vitamin K2 could help reduce risk for heart disease. Researchers believe vitamin K2 prevents the build-up of calcium in arteries (7), which is a major risk factor in developing heart disease.
A European study spanning 7 to 10 years found participants who ingested the highest levels of vitamin K2 developed calcification of the arteries at a 52% lower rate than those who got the least, and were 57% less likely to die of heart disease. (8)
When data from a large study of more than 16,000 women was analyzed, the results showed subjects reduced the risk of developing heart disease by 9% for every 10 micrograms of vitamin K2 taken. (9)
In these observational studies, intake of vitamin K1 had no effect on outcomes. Since cardiovascular disease is the leading cause of death worldwide today (10), clinical trials to determine the role vitamin K2 can play in prevention are vital.
When important micronutrients are missing from the diet, any number of bodily processes can go awry.
Vitamin K2 could improve bone health. Elderly western women are particularly vulnerable to this disease in which bones become more porous and fracture easily.
When menopausal women took K2 supplements over a three-year period, they experienced reduced rates of declining bone mineral density in comparison to women who took no supplements. (13)
After conducting 13 separate trials, Japanese medical authorities recommend high doses of vitamin K2 supplements to prevent and treat osteoporosis. (14)
Only one of these lengthy trials failed to show significant improvement in bone density; more than half the studies confirmed that the occurrence of bone fractures in subjects taking K2 decreased by impressive rates: between 60% and 81% for hip, spinal and non-spinal fractures. (15).
Vitamin K2 could improve dental health. Dr. Weston Price believed vitamin K2 was vital for preventing cavities and promoting good oral health, but his theory has not been tested on humans.
Animal studies exploring the role of K2 in bone health indicate a potential link between strong bones and good teeth.
Osteocalcin, the protein important for bone metabolism, also regulates proteins vital for dental health. (18) The growth of new dentin underneath tooth enamel appears to be stimulated by osteocalcin. (19)
Researchers believe vitamin K2 may work in concert with vitamins A and D in keeping teeth strong and free of cavities. (20)
A wide range of foods can provide vitamin K2. Vitamin K1 is present in a typical diet at approximately ten times the amount of vitamin K2; since the body can convert K1 to K2, this is helpful. But it’s an inefficient process, and eating foods rich in K2 is a good way to make certain you get enough.
Unfortunately, foods rich in vitamin K2 aren’t on the top of everyone’s grocery list. Animal foods are good sources of a vitamin K2 subtype called MK-4, and fermented foods help you get subtypes MK-5 through MK-14. (21)
Include these for the first subtype: Dairy products, high-fat and only from grass-fed cows, including cheese and butter, liver and other organ meats and egg yolks.
Fermented foods aren’t eaten as often in modern times, but these are excellent sources of other vitamin K2 subtypes: Miso and natto, fermented soy products and sauerkraut.
Vitamin K2 is fat-soluble, which means the body can access the nutrient only when combined with fat; lean meats have limited amounts of vitamin K2.
Supplements are widely available at reasonable cost, and may be more effective when taken with vitamin D. While the RDA for K2 is 1500 micrograms, dosages up to 45 milligrams (45,000 micrograms) have been safely used in test protocols.
Vitamin K2 is extremely safe. No health risks from excessive vitamin K intake have been identified, either from supplemental vitamin K2 or any form of vitamin K found in foods (22).
Some heart disease experts caution that you should talk to your doctor before you change your vitamin K intake (including by starting or stopping a supplement with vitamin K2 in it, which includes many multivitamins for men and for women).
That’s because warfarin and other blood thinners are specifically designed to block the clotting action that is promoted by vitamin K. Warfarin, though, interacts with an enormous range of supplements—even fish oil isn’t exempt from warfarin interaction (23).
Unless you take warfarin or another prescription blood thinner, you should not have to worry about any adverse effects related to vitamin K2 intake.
New research has indicated that the recommended intake of vitamin K2 should be substantially higher than it previously was. As of January of 2020, all food labels must now use an updated target of 120 mcg per day.
This matches the most recent recommendations from the Office of Dietary Supplements at the National Institutes of Health, which cites a target intake of 120 mcg per day for adult males and 90 mcg per day for adult females (24).
About one-third of adults in the US have vitamin K intake in their diet that is lower than the adequate intake levels, which has raised some concern about dietary sources of vitamin K. Since the best sources of vitamin K tend to be healthy vegetables like broccoli, kale, and collard greens, striving to hit 90-120 mcg of vitamin K per day with dietary changes is best.
However, if that’s not possible, a supplement can be a better choice: supplements have much higher bioavailability than vitamin K2 that’s bound up in plant material, so people with vitamin K2 deficiency or who are at risk for vitamin K2 deficiency can increase their K2 levels more efficiently with a supplement.
When it comes to supplemental research, most studies use daily doses in the vicinity of 100 to 200 mcg per day.
While this is right around the recommended daily intake, it’s important to remember that supplemental K2 is absorbed much more effectively than vitamin K2 that’s found natural sources (especially the K2 that is in vegetables, which is quite difficult to absorb).
Q: Who is at risk for vitamin K2 deficiency?
A: Most Americans get enough vitamin K2 in their diet to mee the necessary vitamin K2 intake levels for health. However, a very poor diet, and certain health conditions that impede vitamin K2 absorption can cause deficiency.
If, like about one third of American adults, your diet is very low in green leafy vegetables and plant oils, you might consider a supplement for vitamin K2.
Additionally, people with celiac disease or people who have had any type of gastric bypass, lap band, or other weight loss surgery are often at risk for vitamin K2 deficiency, as their ability to absorb vitamin K from their diet is impeded.
Q: What foods are rich in vitamin K2?
A: You can find vitamin K2 specifically in fermented foods, like cheese, miso, tempeh, or natto. Other forms of vitamin K are readily found in green leafy vegetables like broccoli, kale, and collard greens.
Though your body is quite capable of absorbing vitamin K in any of its forms, vitamin K that is found in vegetables is thought to be absorbed less efficiently than vitamin K2 from a supplement.
Q: Is vitamin K2 safe to take?
A: Yes, in fact vitamin K2 is so safe that no upper limits on intake have been identified. For example, a 2001 report by the Institute of Medicine noted that no adverse effects from vitamin K intake have been identified, either in humans or in animals (25).
This includes both supplemental version of vitamin K2 and dietary sources of vitamin K in all of its forms. The only caveat to this is that people who are currently taking warfarin or other blood thinners should talk to their doctor before changing their vitamin K intake levels, because warfarin’s mechanism of action specifically interferes with the kind of clotting that vitamin K promotes.
Q: What is the difference between vitamin K and vitamin K2?
A: Like vitamin B, vitamin K is an umbrella term that refers to a family of related compounds: vitamin K1, vitamin K2, and vitamin K3. If that’s not confusing enough, vitamin K2 comes in two different forms, MK-4 and MK-7 (26).
The MK-4 form is found in butter, eggs, lard, and other animal products (often because a synthetic form of MK-4 is added to animal feeds). It’s also synthesized by bacteria in your gut, but whether this leads to any meaningful change in your body’s vitamin K absorption is debated in the scientific community).
The MK-7 form lasts slightly longer in your body, and can be found in fermented foods and cheeses. Supplemental vitamin K2 can be in either the MK-4 or the MK-7 form, and aside from slight differences in how long each form stays in your body, there is very little evidence as to whether it matters what form you get your vitamin K2 in.
Q: Does vitamin K2 interact with vitamin D3?
A: Vitamin K2 and vitamin D3 are commonly combined in supplements because of a potential synergistic effect on bone density. Both vitamin D and vitamin K contribute to bone density.
Multiple scientific studies on postmenopausal women suggest that combined D3 / K2 supplements can improve bone density, possibly reducing the risk of fractures as you get older. Of course, none of these make sense without adequate calcium intake, but that almost goes without saying if you are trying to increase your bone strength.
Q: What vegan foods are high in vitamin K2?
A: Unlike some other vitamins, such as vitamin B12, vegans actually have it pretty easy when it comes to getting adequate vitamin K intake overall. Vegan favorites like kale, broccoli, soy, and collard greens are all very high in vitamin K.
If you are specifically looking for vitamin K2 it can be a bit trickier, but fermented soy products like tempeh, miso, and natto are all great bets.
The science is far from conclusive on whether the form of vitamin K that you get even matters—what does matter is the overall amount of vitamin K in your diet. Shoot for at least 120 mcg for men, and 90 mcg for women.
Q: What is vitamin K2 MK-7?
A: Vitamin K2 comes in two forms: MK-4 and MK-7. The MK-4 form is synthesized by bacteria that are found in animal digestive tracts (including yours), and this MK-4 form is often added to animal feed.
Animals that eat this feed, like chickens and cows, end up with MK-4 form of vitamin K2 in the food they produce, like eggs, butter, or meat. In contrast, the MK-7 form is found in fermented foods, particularly soy-based foods like natto.
The MK-7 form has a longer elimination half-life in your body, but aside from this difference, scientists don’t know yet if there are any meaningful nutritional differences between the MK-4 and MK-7 forms of vitamin K2 (or indeed, any meaningful differences between vitamins K1, K2, and K3) (27).
Q: Where does vitamin K2 come from?
A: Vitamin K2 in supplements is going to be one of two forms: MK-4 or MK-7. The MK-4 form is extracted from specific bacteria that produce this form of vitamin K2, while the MK-7 form is isolated from natto, a fermented soy product.
Scientists don’t really know if there are any significant nutritional differences between the two types of vitamin K2, so while you can find both on shelves in supplemental form, it’s too early to say whether one is superior to the other.
If you have any doubts that you’re getting enough vitamin K2, adding rich food sources to your diet or taking a supplement could help you improve both your bone strength and your heart health.
For BodyNutrition‘s #1 vitamin K2 recommendation, click here.