5 Best Vitamin K Supplement Capsules (K1, K2, MK4, MK7) and Dosages
If you have found your way here to this page, then I am guessing you have at least heard of vitamin K.
A lot of people haven’t.
Despite that fact, vitamin K is a big deal. It’s an essential nutrient which your body needs to function.
Thankfully, people are finally starting to learn about vitamin K. That means we’re also seeing more people asking about vitamin K supplements.
Do you need a vitamin K supplement? How do you shop for the best one? What form of vitamin K do you need?
There are a lot of questions to answer, so let’s get started.
What is Vitamin K?
First of all, there is a chance you are still not that familiar with vitamin K, so let’s quickly go over the basics.
Vitamin K is actually not just one nutrient. It is a group, rather like vitamin B.
Just as there is more than one B vitamin (i.e. B6, B12, and so on), there is more than one K vitamin.
All K-vitamins are fat-soluble. They are involved with a number of bodily processes, but the two primary ones are:
- Calcium binding
- Blood coagulation
The "K" in the name vitamin K actually is short for "koagulation." The reason for the spelling is that this is the Danish form of the word.
Being as vitamin K wasn’t even discovered until the 1920s and 30s, it is understandable that it hasn’t received as much attention as some other important nutrients.
What did eventually lead to the discovery of vitamin K was a situation involving animals on restricted diets.
These animals were not getting enough vitamin K, and as a result were bleeding uncontrollably (1).
Scientists today know that vitamin K is vital for proper coagulation.
KEY POINT: Vitamin K is an essential nutrient which a lot of people do not know much about.
It was discovered during the early part of the 20th century, and is only now starting to come into the spotlight.
Among other functions, it is vital for blood clotting as well as calcium binding in your bones.
Both Vitamin K1 and Vitamin K2 Are Important
While reading about vitamin K, you may have heard that there are two principle types of K vitamins: vitamin K1 and vitamin K2.
Vitamin K1 is also called "phylloquinone," but you will almost never see anyone refer to it that way.
You get vitamin K1 largely through vegetable sources.
Nonetheless, we are not that great at absorbing it. Typically we absorb only around 10% (3).
Vitamin K2 is harder to come by from dietary sources, and is found mainly in fermented foods and animal products.
We are more efficient at absorbing vitamin K2 (4). This likely has to do with two facts.
First of all, vitamin K2 sources are fatty, and vitamin K1 sources are not, and vitamin K is fat-soluble in both cases.
Secondly, the structure of vitamin K2 is conducive to extended circulation in the bloodstream.
Vitamin K1 is out of your blood within hours, but vitamin K2 can circulate for days (5).
To add to the complexity, vitamin K2 comes in a number of different forms which are identified according to the lengths of their side chains.
The different forms of vitamin K2 are called "menaquinones." Usually you will see this shortened to “MKs.”
The format is always MK-(N), where N is a number referring to the side chain length.
So for example:
Indeed, the side chains range in length between 4 and 15.
Different forms of vitamin K2 are useful for different purposes. I will get into this in detail shortly.
KEY POINT: Vitamin K is available as vitamin K1 and vitamin K2. Vitamin K2 in turn is further subdivided into MK- subtypes.
Health Benefits of Vitamin K
Vitamin K has numerous different benefits for health.
Here are a few reasons to make sure you are getting plenty of vitamin K in your diet:
- Boost bone health (6).
- Prevent heart disease (7).
- Strengthen teeth (8).
- Decrease inflammation throughout your body (9).
- Fight autoimmune diseases (10).
- Prevent cancer (11).
- Protect your brain health and possibly help counteract dementia (12).
- Reduce menstrual pain and bleeding (13).
- Boost the function of your mitochondria, increasing energy (14).
- Reduce insulin resistance and treat diabetes (15).
- Protect against harmful effects from statins, warfarin, and vegetable oils (16).
- Ensure your blood clots as it should (37).
- Increase longevity (11).
- Prevent BVC when taking high doses of vitamin D (17).
If you want to learn about these health benefits in-depth, you should check out my article Health Benefits of Vitamin K.
KEY POINT: Vitamin K is best known for its roles in protecting bone strength and promoting clotting, but it has further applications for protecting heart and brain health, treating insulin resistance, and possibly even fighting cancer.
Can You Increase Your Intake of Vitamin K Through Food Sources?
Now that you know the importance of vitamin K, you are probably wondering if you can just get what you need through food instead of relying on a supplement.
Generally speaking, most people do manage to get enough vitamin K through diet.
Vitamin K1 sources include (18):
- Kale: 1,062 mcg
- Collard greens: 1,059 mcg
- Spinach: 889 mcg
- Turnip greens: 529 mcg
- Broccoli: 220 mcg
- Brussels sprouts: 218 mcg
So simply by increasing your intake of vegetables, especially the leafy green variety, you can give yourself a vitamin K1 boost.
- Natto: 1,062 mcg
- Pork sausage: 383 mcg
- Hard cheeses: 76 mcg
- Pork chop (with bone): 75 mcg
- Chicken (leg/thigh): 60 mcg
- Soft cheeses: 57 mcg
- Egg yolk: 32 mcg
Take note that most of these foods are animal products.
If you are a vegetarian or vegan, this may make it extra challenging for you to get the vitamin K2 that you need.
Other food-based sources of vitamin K include pumpkin, carrot juice, okra, pomegranate juice, blueberries, pine nuts, Caesar salad dressing, iceberg lettuce, grapes, chicken breast, cashews, raw carrots, and vegetable juice.
KEY POINT: You can get vitamin K through your diet. Most K1 sources are veggies, and most K2 sources are animal-based.
How Much Vitamin K Should You Be Getting in Your Diet?
Here is how much vitamin K is recommended based on your age and sex (22):
Birth to 6 months
For pregnant and lactating women, vitamin K requirements are unchanged.
KEY POINT: If you are a man, you should be getting around 120 mcg of vitamin K daily. If you are a woman, you should be aiming for around 90 mcg.
Could You Have Vitamin K Deficiency?
Most people do not need to worry about vitamin K deficiency, as it is relatively rare.
But you may be at a higher risk if you are a member of any of the following groups:
- Those with absorption issues. This can happen at any age, and is typically the result of short bowel syndrome, celiac disease, cystic fibrosis, ulcerative colitis, or so on. But you might also see it on its own.
- Those taking medications which may interact with vitamin K (see the section on interactions).
- If you recently had bariatric surgery, you might develop vitamin K deficiency.
- Vegans and vegetarians might be deficient in vitamin K2. Since most vitamin K2 comes from animal products, it is easy to miss out on it if you are not deliberately looking for ways to introduce it into your diet.
- If you are pregnant or the parent of a newborn, you should be extra mindful of your child’s vitamin K status. When your baby is born, he or she must receive vitamin K treatments since the placenta doesn’t do well transferring vitamin K. If these treatments are not administered, a dangerous condition called vitamin K deficiency bleeding (VKDB) may result.
So even though vitamin K deficiency is uncommon in general, it does happen, and some groups are more likely to be susceptible to it than others.
KEY POINT: The general population on the whole does not need to concern itself with vitamin K deficiency.
Certain groups however should consider supplementing with vitamin K to avoid deficiency.
These include those taking certain medications or recovering from bariatric surgery, as well as people with absorption issues.
Additionally, infants can experience VKDB if they do not receive vitamin K treatments when they are born.
Is There an Upper Limit for Vitamin K?
You now know how much vitamin K you are supposed to be getting each day, and you know the food sources for it.
If you are thinking about taking vitamin K supplements however, you may be concerned about overdoing it.
Actually, no formal upper limit has even been established for vitamin K (22).
The Food and Nutrition Board has explained this decision with the statement that "no adverse effects associated with vitamin K consumption from food or supplements have been reported in humans or animals."
Of course, it is always possible to have too much of a good thing, so you should avoid excessive doses.
But you should be just fine so long as you are taking regular dosages.
KEY POINT: The Food and Nutrition Board has found no adverse effects from vitamin K supplementation or dietary intake, and as a result has never set an upper limit.
Watch Out For Vitamin K Interactions
As briefly mentioned already, there are some drugs which interact with vitamin K.
Here is a summary of interactions which may occur:
A good example is warfarin.
If you take an anticoagulant, it will counteract vitamin K’s activity in the body. This is the point of taking this type of medication in the first place.
It is important to absorb a healthy, steady amount of vitamin K while on anticoagulants or unexpected and adverse results may occur during treatment.
Talk to your doctor to establish an appropriate amount.
These actually produce vitamin K, so if they get wiped out by the antibiotics, they will no longer contribute to your supply.
This may necessitate taking vitamin K supplements for a while.
Bile acid sequestrants.
You take these drugs in order to lower your cholesterol levels.
The downside is that your body may struggle to absorb fat-soluble nutrients while you are on them. Vitamin K is one of those, so you might need to supplement with it over the course of your treatment.
If you are trying to lose weight, you might end up taking this medication. It works by hindering your ability to absorb fat.
This also makes it hard to absorb vitamin K unfortunately. You might need to take a supplement while you are on the medication.
KEY POINT: Some medications interfere with vitamin K. Talk to your doctor about vitamin K if you are taking any of the drugs discussed.
In some cases, supplementation may be indicated.
What Forms of Vitamin K Supplements Do You Need
Now let’s get back to the complicated bit about vitamin K coming in different forms.
You may feel dizzy sorting through so many MK’s, especially given the conflicting information you might come across.
Then there are questions of natural versus synthetic vitamin K, and so on.
Let’s break it down.
Do You Need Vitamin K1 Supplements?
Vitamin K1 is essential for human health, so you definitely need it in your diet.
But do you need to supplement it? Probably not.
You do not need to eat a whole lot of leafy green vegetables in order to get an adequate amount of vitamin K1 (23).
Soybean oil and fast food aren’t healthy for you in general, but at least vitamin K1 is one upside to eating them on occasion.
On the other hand, a lot of that K1 ends up being transformed through the hydrogenation process into another substance called DHP.
DHP is less readily absorbed and has "no measurable biological effect on measures of bone formation (27)."
So for multiple reasons, leafy green vegetables remain your best bet for getting adequate vitamin K1.
The amount of vitamin K1 in your blood tends to level out around 200 mcg if you are taking supplements (25).
Taking very high doses of vitamin K1 is not necessarily wise. Some research suggests doing so may be a factor in developing periodontal disease (26).
KEY POINT: Vitamin K1 is essential, but you do not necessarily need a vitamin K1 supplement.
Most people are able to get plenty of vitamin K1 just from vegetable food sources.
What Vitamin K2 Supplements Do You Need?
Now let’s talk about vitamin K2 supplements, which you may need to take - especially if you are not eating a lot of fermented foods or animal products.
This is where things get really complicated. But let’s try and make them simple.
You’ll see various MK subtypes of K2 for sale, but mostly you will encounter MK-4 and MK-7.
If you are taking vitamin K2 supplements for brain health …
The type of vitamin K2 found in your brain is MK-4 (28), where it plays the important role of activating Vitamin K Dependent Proteins (VKDP).
These proteins provide support for the cell membranes in your brain.
Additionally, MK-4 reduces oxidative stress and inflammation in your brain, providing a further protective effect.
If you are taking vitamin K2 supplements for bone health …
MK-7’s half-life is longer than MK-4’s. This makes it a good choice to support the health of bones and teeth.
On the other hand, MK-4 is being prescribed in high dosages in Japan to treat osteoporosis (29).
Research indicates (30) that this is the type of vitamin K2 you should take to reduce your risk of developing fractures.
If you are pregnant …
You will need to take MK-4. MK-4 is able to transfer across the placenta, but MK-7 cannot.
Note that your baby will still need to receive vitamin K treatments when he or she is born!
While breastfeeding, you should continue taking MK-4 supplements as this is the kind of vitamin K2 that makes it into breast milk.
For gene regulation and cellular function …
Pick the Right Form of Vitamin K2 For Your Needs
So to sum up, neither MK-7 nor MK-4 is really "better" than the other.
It is true that MK-7 circulates longer, but MK-4 is easily and rapidly absorbed. The tissues that absorb MK-4 put it to good use.
- For bone health, you can try MK-4 or MK-7, but MK-4 is probably superior for preventing fractures.
- For brain health, you need MK-4.
- If you are pregnant or breastfeeding, you need MK-4.
- If you are supporting cellular function and gene regulation, you need MK-7 and MK-4.
KEY POINT: Different forms of vitamin K2 are ideal for different purposes. Most people will probably want to take the MK-4 form, but there may be cases where you want MK-7.
Is It Important to Shop for "Natural" Vitamin K?
If you are trying to go "all natural" with your supplement use, you may have seen that MK-4 products are typically considered to be "synthetic" while MK-7 products may be promoted as a "natural" alternative.
Whether MK-7 is "natural" or not depends on your definition of natural.
Technically, both MK-4 and MK-7 products are derived from natural ingredients.
The process used to convert the nutrients into supplement form however is not natural.
It is quite extensive, involving not just fermentation of the ingredients, but also purification, extraction, and even precipitation (33).
That being said, some of these products, like those derived from Natto or garbanzo beans, are bio-identical.
That is as close to "natural" as you are going to get without simply sticking with the original food sources.
KEY POINT: Even though some vitamin K2 products are marketed as being “natural,” they are arguably not, because they have been heavily processed.
It is not necessarily all that important to shop for a “natural” supplement as a result.
Cis Versus Trans MK-7
Now, just to make matters a little more complicated, MK-7 molecules come in different shapes.
These shapes are called "isomers."
They are Cis MK-7 and Trans MK-7.
The Trans isomer of MK-7 is found naturally in food sources.
The Cis isomer on the other hand is not.
The natural Trans form is bioavailable and can readily be used by your body. This is not the case with the Cis form (34).
A lot of manufacturers of vitamin K2 products do not bother to tell you what percentages of each isomer are present in their supplements.
Since you may not find this information on the label, it can be hard to know what you are getting.
The University of Oslo/KappaBio ran a study which has not been published on the origin countries for MK-7 and the percentage of Trans MK-7 found on average in the supplements from each (36).
Here are the findings:
- Norway: 98% Trans
- Japan: 95% Trans
- Europe: 89% Trans
- India: 71% Trans
- China: 15-30% Trans
So when in doubt, avoiding products from China is probably wise, and favoring products from Norway or Japan may be sensible.
Of course, there are always exceptions.
Now, what about products manufactured from Natto? These tend to be the supplements which are promoted as "all-natural."
Remember, they are not. They have been processed heavily.
Does this mean that their molecular structures are altered?
The problem is that it is hard to know, because hardly any manufacturers bother to test for this.
Hopefully we will see more attention brought to this issue in the near future. Until then, shop with care, and just be aware that this issue exists.
KEY POINT: There are two isomers of MK-7: Trans and Cis. Your body can use Trans, but not Cis.
Unfortunately, it is really hard (if not impossible) to know whether the MK-7 you are purchasing consists mainly of Trans or Cis isomers.
Watch Out for Soy Products
Quite a few vitamin K2 products are made using soy.
Whether this is problematic for you or not depends on whether you eat soy or you avoid it.
Soy does pose some potential health concerns. It can for instance throw off your hormonal balance (35).
If you do not want to eat soy, just make sure that you are purchasing a vitamin K product which was not made using it.
KEY POINT: Many vitamin K2 products are made from soy. If you are avoiding soy, be extra mindful that you purchase a non-soy vitamin K2 supplement.
What Do You Need to Look for in a Vitamin K Supplement?
When you are shopping for vitamin K2 supplements, here is a checklist of what you need to be on the lookout for:
The right type of vitamin K for your needs
Based on the condition you are trying to treat or the health goal you want to achieve, decide whether you want K2 MK-4, MK-7, or a combination of the two.
Some products also include K1.
Trans vitamin K2
If possible, shop for vitamin K supplements which contain a high percentage of the trans isomer.
Keep in mind however that you may find little or no information on this, so you may be down to guesswork.
If soy is something that you are avoiding, then make sure that the product you are purchasing is not soy-based.
The dosage you need
Try and determine how much vitamin K you are getting from food sources, and figure out the appropriate dosage accordingly.
The right price
Saving money is always a plus, so long as you are getting a quality product. Try and find the vitamin K supplement which represents the best value.
Easy to swallow
If you have a hard time swallowing pills, shop for smaller vitamin K pills which will not give you trouble.
Purity is always vital when shopping for supplements.
Check both the active and inactive ingredients in the vitamin K product you are thinking of purchasing.
If you can, pick a product which contains minimal or no additives.
Has the product you are considering purchasing been tested for quality and purity by a third party?
Look for indications of quality control before selecting a product. Stick with products manufactured in labs that follow cGMP practices.
If the brand you are buying from has a strong reputation, that is a plus. If you are not familiar with the brand, do some research.
Check out their reviews, and also look over their website and sales pages to see if they tend to be upfront and transparent about their products.
Solid customer support
If you have questions about the vitamin K supplement you are purchasing, you are going to want to deal with a company that will provide you with the answers you need.
Try and shop from manufacturers that go out of their way to help out customers when they need it.
KEY POINT: As with any other supplement, you should shop around before you select the vitamin K product you want to buy.
You need to make sure it is high in quality and will fit your needs.
Tips for Reading Vitamin K Supplement Reviews from Customers
I am going to share my recommended vitamin K supplements with you shortly.
But first, I want to provide you with a little advice for reading and evaluating vitamin K supplement reviews.
While clicking through the products I am sharing, you will probably decide to scroll through customer reviews and read them.
This is definitely something I encourage, but it is important to remember that customer reviews online have limitations.
This is true with all supplements, but with vitamin K in particular, it is important to keep in mind. Here are my tips:
First of all, take “this product cured me of X ailment” reviews with a grain of salt.
While they are encouraging, customers who post them cannot necessarily prove it was the supplement that provided them with their "cure."
Other lifestyle factors could account for their success.
Instead, focus on the basic provable facts. What does the supplement contain? What company manufactured it? Is it vegetarian-friendly?
Answering questions like this is ultimately far more informative (this goes for any supplement, not just vitamin K).
Be leery of MK-7 obsessed customers and manufacturers.
There are loads of people out there who seem intent on convincing the world that MK-7 is the ultimate superior form of vitamin K, either because it is "natural" or circulates longer.
As you already know, this is not necessarily true.
Reviews which try and pound this into your head may be posted by manufacturers as part of a marketing campaign, or simply by misinformed customers.
Watch out for the natto obsession as well.
Natto-derived vitamin K is a great option, but once again, it may not be as “natural” as you think.
Nonetheless, many customers and manufacturers will insist it is the only vitamin K worth taking.
KEY POINT: In short, there is a lot of marketing hype which attempts to manipulate consumers who may be confused about all the forms and subtypes of vitamin K on the market.
Read reviews and product descriptions with a critical eye, and try not to be taken in by these questionable hard-sells.
How to Take Vitamin K Supplements
Once you have your vitamin K supplements, how do you take them appropriately?
Take a look at the back of the bottle you purchased and follow the directions.
In most cases, it is as simple as taking one vitamin K capsule every day with a meal.
Remember, vitamin K2 is fat-soluble.
That means that if possible, you should try to take it with a fatty meal.
This should help to maximize absorption.
KEY POINT: Using a vitamin K supplement usually entails taking a capsule each day with a meal.
If you want to boost absorption, make sure that you are eating some kind of fat when you take your supplement.
Top Recommended Vitamin K Supplements For 2018
Now that you know all about how to shop for the right vitamin K supplement, here are some recommendations in each category.
You will notice while browsing that most vitamin K supplements include a combination of vitamin K forms.
If you are looking for a highly rated and popular supplement to take which includes only the MK-4 form of vitamin K2, consider this high dosage product.
The only drawback is that it is not fully vegetarian.
- 60 capsules.
- 5 mg of vitamin K2 MK-4 (Menatetrenone).
- Other ingredients: Magnesium stearate, microcrystalline cellulose, silicon dioxide, vegetable stearin, beef gelatin capsule.
- Contains no soy.
What Carlson Vitamin K2 MK-4 is Best For
Take this supplement if you want to give your body a potent dose of vitamin K in the MK-4 form, and do not want to take MK-7 or vitamin K1.
For example, this would be a good choice for brain health since you are paying only for the type of vitamin K that your brain uses.
NOW is one of the best-known brands in the world of health products.
Their MK-7 vitamin K2 product is popular and well-received by customers.
- 120 capsules.
- 100 mcg vitamin K MK-7.
- Also contains 2 mg of vitamin C.
- Other ingredients include cellulose, rice flour and silica.
- Contains non-GMO soy.
What NOW MK-7 is Best For
Vitamin K2 MK-7 is vital for certain functions in the body.
If you need it to fill a dietary gap or to compensate for the action of a medication you are taking, this product will give you what you are after.
Hopefully you understand now why MK-7’s “natural” status is rather overblown, but if you still are convinced that it is a superior form, you can take it for that reason as well
If you are shopping for a product which contains the full spectrum of popular vitamin K forms, this is it.
Bronson Vitamin K Triple Play contains Vitamin K1, Vitamin K2 MK-4, and vitamin K2 MK-7.
Like the other supplements I’ve included in this list, it is popular and highly rated by online buyers.
- 550 mcg vitamin K (total for all forms combined, see breakdown below).
- 100 mcg of vitamin K1.
- 400 mcg of vitamin K2 MK-4.
- 50 mcg of vitamin K2 MK-7.
- 180 capsules.
- Other ingredients include silicon dioxide, microcrystalline cellulose, magnesium stearate, and gelatin.
- 365-day money back guarantee.
What Bronson Vitamin K Triple Play is Best For
The Bronson Vitamin K Triple Play is an excellent choice if you want to make sure that you are covering all of your vitamin K needs.
Considering that the supplement contains ample amounts of all three vitamin K forms, it is a great deal for the money.
Another option if you want more than one type of vitamin K is this Super K with Advanced K2 Complex from Life Extension.
This product contains higher dosages than the Bronson Vitamin K Triple Play supplement.
- 90 softgels.
- 1,000 mcg vitamin MK-4.
- 200 mcg vitamin MK-7.
- 1500 mcg vitamin K1.
- 10 mg vitamin C.
- Additional ingredients include gelatin, extra virgin olive oil, beeswax, glycerine, carob color, and purified water.
What Life Extension Super K is Best For
Consider this product if you want to get high doses of vitamin K1, vitamin K2 MK-4 and vitamin K2 MK-7 all at once for a reasonable price.
For a lower dosage, consider the Bronson Vitamin K Triple Play.
Another popular supplement you can buy which contains all three forms of vitamin K is this one from Peak Performance.
It too has received stellar ratings and is available at a reasonable price.
It comes with vitamin D as well, eliminating the need to purchase a separate vitamin D supplement.
- 60 capsules.
- 100 mcg vitamin K1.
- 100 mcg vitamin K2 MK-7.
- 25 mcg vitamin K2 MK-4.
- 5,000 IU vitamin D.
- 5 mg of bioperine.
- Made in the USA.
- Contains no egg, soy, milk, corn, peanuts, wheat, gluten, preservatives, fillers, or binders.
What ADVANCED Vitamin D 5000 IU + ALL 3 Types Of Vitamin K is Best For
This is a lower dose combination of vitamin K1, vitamin K2 MK-4 and vitamin K2 MK-7.
Use it if the Bronson product contains more vitamin K than you are looking for.
It also makes a great choice if you want to take your vitamin K in conjunction with vitamin D to enhance the performance of both.
Conclusion: Shopping for Vitamin K Supplements Can Be Complicated, But You Now Know Where to Start
The first time you shop for vitamin K supplements, you may feel intimidated by all the technical details.
But you now should have a pretty good idea what types of vitamin K supplements are out there and which would potentially be the best fit for your needs.
You also have some great product recommendations to help you out.
Take your time and do your research, and you should be able to find a high quality vitamin K supplement which can provide your body with exactly what it needs to function at its best!
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