Vitamin K sounds simple until you meet vitamin K2, and then MK7 shows up and makes it even more confusing. If you’ve seen vitamin K2 MK7 on supplement labels, you’ve likely heard big claims about bones, arteries, and heart health. Some of that hype goes too far. Still, MK7 has a real role in the body, and it can be useful in the right context.
This article breaks down what vitamin K2 MK7 is, how it works, what the research actually suggests, and how to make smart choices about food and supplements.
Vitamin K, K1, K2, and MK7: a quick map
Vitamin K is a group of fat-soluble nutrients. Your body uses them to switch on proteins involved in blood clotting and in how your body handles calcium.
Vitamin K1 (phylloquinone)
K1 mainly comes from leafy greens like spinach, kale, and broccoli. It supports normal blood clotting. Many people get most of their vitamin K from K1.
Vitamin K2 (menaquinones)
K2 is a family of forms called menaquinones, often written as MK-n (where “n” relates to the length of a side chain). Two common forms in supplements are MK4 and MK7.
- MK4: found in small amounts in animal foods and can be made in the body from K1.
- MK7: found in fermented foods and tends to stay in the blood longer than MK4.
That longer “stay time” is one reason vitamin K2 MK7 is so popular in supplements.
What vitamin K2 MK7 does in the body (in plain English)
Vitamin K2 helps activate certain proteins by a process called carboxylation. That word isn’t worth memorizing. What matters is what those proteins do once they’re switched on.
It helps direct calcium to the right places
Two vitamin K-dependent proteins get most of the attention:
- Osteocalcin: helps bind calcium in bone tissue.
- Matrix Gla protein (MGP): helps limit calcium buildup in soft tissues like blood vessels.
People often summarize this as “K2 puts calcium into bones and keeps it out of arteries.” That’s a neat line, but biology is messier. Still, this is the core idea behind MK7 use for bone and heart health support.
It also supports normal blood clotting (but K1 leads here)
Vitamin K’s classic job is helping blood clotting factors work. K1 plays the bigger role, but K2 contributes. This matters if you take blood thinners.
For a solid overview of vitamin K’s roles, see the NIH Office of Dietary Supplements vitamin K fact sheet.
MK7 vs MK4: what’s the real difference?
Both are vitamin K2, but they behave differently.
- MK7 tends to circulate longer, so smaller daily doses can maintain steadier blood levels.
- MK4 clears faster, and studies often use much higher doses of MK4 to see effects.
That doesn’t automatically make MK7 “better.” It just makes it easier to use as a once-a-day supplement.
Food sources of vitamin K2 MK7 (and why they’re rare)
Most diets don’t include many rich K2 foods. That’s not because K2 is exotic. It’s because K2 forms when bacteria transform nutrients during fermentation, or when animals convert and store it.
Top sources people actually eat
- Natto (fermented soybeans): the standout source of MK7
- Some aged cheeses
- Fermented foods (varies a lot by product and process)
- Egg yolks and some meats (more often MK4 than MK7)
Natto deserves special mention. It’s the reason MK7 exists as a “food-based” supplement at all. If you can tolerate the flavor and texture, natto can be a practical way to get MK7 without pills.
To see how public health groups talk about vitamin K in foods and daily needs, check the Harvard T.H. Chan School of Public Health overview of vitamin K.
What the research says about vitamin K2 MK7
Vitamin K2 research is active, but it’s not as settled as many supplement ads imply. The strongest human data sits in bone health, with more mixed results for cardiovascular outcomes.
Bone health: where MK7 looks most promising
Several studies suggest MK7 can improve markers related to bone metabolism and may help maintain bone mineral density, especially in older adults with low vitamin K intake. The effect size varies, and results depend on dose, baseline diet, vitamin D status, and calcium intake.
Also, fracture prevention is the gold standard. Not every study measures fractures, and not every study runs long enough to see them.
If you want a deeper, research-focused read, the PubMed Central database is a useful place to find full-text reviews and trials. Search “menaquinone-7 bone mineral density” and filter for human studies.
Heart and artery health: plausible, but not a magic shield
The MK7 story here comes from MGP, which helps prevent calcium deposits in vessel walls. Observational studies have linked higher K2 intake with better cardiovascular outcomes in some populations, but observational work can’t prove cause and effect.
Intervention trials show changes in biomarkers (like inactive MGP) more consistently than they show hard outcomes (like fewer heart attacks). That doesn’t mean MK7 is useless. It means you should treat it as one piece of a bigger plan: blood pressure control, exercise, sleep, and a diet that supports healthy lipids.
Teeth and gum health: early interest, limited proof
You’ll see claims that K2 “remineralizes teeth.” The logic comes from the same calcium-handling proteins. But human evidence is still thin. If you’re focused on dental health, you’ll get more reliable returns from fluoride use, good brushing habits, and regular cleanings.
Who might consider vitamin K2 MK7?
Most people don’t need to panic about K2. But some groups may want to look closer.
You might benefit if you:
- Rarely eat fermented foods or dairy and have low dietary K2
- Have osteopenia or worry about age-related bone loss (especially post-menopause)
- Take vitamin D supplements and want to cover the “calcium management” side
- Have a restricted diet that limits K-rich foods
That said, food comes first when you can manage it. Supplements make sense when diet won’t get you there, or when a clinician suggests it.
How to choose a vitamin K2 MK7 supplement
Supplements vary a lot. These details help you avoid low-quality picks.
1) Look for MK7 (menaquinone-7) clearly listed
Some labels say “vitamin K2” without stating the form. If you want MK7, the label should say MK7 or menaquinone-7.
2) Check the dose range
Common daily doses in supplements often sit around 90-200 mcg. More isn’t always better, especially if you don’t know your baseline intake.
3) Prefer third-party testing when possible
Quality testing helps with purity and dose accuracy. You can also look up basic supplement guidance from practical, consumer-focused sources like ConsumerLab’s supplement testing and reports (subscription-based) or check if a product carries USP or NSF marks.
4) Pay attention to the oil base
Vitamin K is fat-soluble. Many MK7 supplements come in softgels with oil (like olive oil). That can help absorption. Capsules can still work, but you should take them with a meal that contains some fat.
How to take MK7 for best results
Take it with food
A meal with fat helps absorption. Breakfast with eggs, yogurt, or avocado works well for many people.
Be consistent
If you use MK7, take it daily for a steady intake. MK7 lasts longer than MK4, but consistency still matters if you’re targeting bone markers over time.
Think in pairs: vitamin D, calcium, magnesium, and K2
K2 doesn’t work alone. Bone health depends on protein intake, strength training, vitamin D, and minerals. If you supplement vitamin D, you may want to ensure your overall plan makes sense, not just add pills.
For helpful context on bone-building basics that actually move the needle, the Bone Health and Osteoporosis Foundation offers practical guidance on nutrition, exercise, and screening.
Safety, side effects, and who should avoid MK7
Vitamin K2 MK7 is usually well tolerated at typical supplement doses. Side effects are uncommon, but “safe” still depends on your meds and medical history.
If you take warfarin (Coumadin), stop and talk to your clinician first
Warfarin works by interfering with vitamin K. Changing vitamin K intake can change how the drug works. This doesn’t mean you can’t ever have vitamin K. It means you need medical guidance and consistent intake.
The American Heart Association’s overview of warfarin and vitamin K explains why consistency matters.
Other medication and health notes
- If you use other anticoagulants, ask your pharmacist or clinician. Some do not interact the same way as warfarin, but you still want expert input.
- If you have liver disease, malabsorption issues, or a history of clotting disorders, get medical advice before supplementing.
- If you’re pregnant or breastfeeding, follow medical guidance. “Natural” doesn’t mean “automatic.”
Common myths about vitamin K2 MK7
Myth: “K2 cleans your arteries”
MK7 supports proteins that help regulate calcium, but no supplement scrubs plaque out of blood vessels. If you care about heart health, focus on the big drivers: blood pressure, LDL, smoking, sleep, and activity.
Myth: “If you take vitamin D, you must take K2”
Some people pair them, and the combo can make sense. But “must” is too strong. Your diet, your dose of D, and your health status matter.
Myth: “More calcium plus K2 equals stronger bones”
Calcium helps when you don’t get enough from food. Past that point, piling on calcium doesn’t guarantee better bones and can cause problems for some people. Strength training and protein often get overlooked, and they matter.
Where to start: simple, realistic steps
If you’re curious about vitamin K2 MK7 but don’t want to overthink it, start here.
- Look at your diet for a week. Do you eat leafy greens, dairy, eggs, or fermented foods?
- If you tolerate it, try a K2-rich food once or twice a week, such as natto or aged cheese.
- If you already take vitamin D, review your plan: dose, blood levels if available, and whether you meet calcium needs through food.
- If you choose a supplement, pick a clearly labeled MK7 product in a moderate dose and take it with a meal.
- If you take warfarin or have clotting concerns, talk with your clinician before you change anything.
Looking ahead: what vitamin K2 MK7 may mean for everyday health
MK7 sits at a useful intersection: bone strength, healthy aging, and the way your body handles calcium over decades. Research will likely sharpen who benefits most, what doses make sense, and which outcomes matter most in real life.
For now, the best move is simple: treat vitamin K2 MK7 as support, not a shortcut. Build your base with food, movement, and the basics that keep bones and vessels healthy. Then, if MK7 fits your needs and your meds allow it, use it with a clear plan and steady habits.
