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Formulated by doctors from
Harvard, Cornell, MIT and Bastyr

Bone Support

Since not everyone needs the same amount of calcium as a dietary supplement, we offer three options, all backed by our “Strong Bones” Guarantee. Each product provides the clinical trial dose of MK4® (45 mg/day) and vitamin D3 (2000 IU/day). The only difference between the formulas is the amount of calcium, so you can customize how much calcium you get. Osteo-K® provides 1000 mg of calcium daily, Osteo-K Minis 400 mg of calcium daily, while Osteo-MK4™ is our calcium-free option.

MK4 has been studied for its health benefits for more than 30 years. It is the most studied form of vitamin K2 for bone health. More than 25 clinical trials with over 7,000 volunteers have evaluated the health benefits of MK4. They show that it promotes healthy bone density, supports healthy bone matrix, and maintains strong bones, as indicated by more than 70% fewer fractures in clinical trials.

Strong Bones. Guaranteed

Your bone density will stabilize or improve in six months, but more importantly, we guarantee you’ll have strong bones. Therefore, if you break a bone, we’ll refund your money for all your purchases since your previous bone scan.

See our guarantee for more details.

Free eBook: Naturally Improve Bone Density and Maintain Strong Bones

Which Osteo-K is Right for You?

How much calcium has your doctor recommended?

If your doctor recommends taking 1,000 mg of calcium as a dietary supplement, you’ll want the original Osteo-K.

If less was recommended, or you believe that less calcium as a dietary supplement is better, then Osteo-K Minis is what you’ll want.

If you don’t need any extra calcium in a dietary supplement, then calcium-free Osteo-MK4 is the perfect choice.

Do you eat dairy?

The US Recommended Dietary Allowance (RDA) for calcium is 1,200 mg daily for women and 1,000 mg/day for men. That’s from all sources—diet plus dietary supplements. The average American woman consumes approximately 800 mg per day of calcium in her diet, and men get about 1,000 mg.

Thus, if you eat an average diet, which typically includes dairy, then Osteo-K Minis is likely the right choice for women and Osteo-MK4 for men. Osteo-K Minis delivers 400 mg of highly absorbable calcium per day. A diet that provides 800 mg of calcium per day, plus the 400 mg in Osteo-K Minis, puts you in the recommended range of 1,200 calcium per day. Osteo-MK4 is NBI’s calcium-free product version for those who don’t need extra calcium in a dietary supplement.

Do you have difficulty swallowing larger capsules?

If you have difficulty swallowing capsules, you can take any of our bone support formulas, open the capsules, mix the nutrients into room-temperature or colder food, such as yogurt or cottage cheese, and consume them that way. This works well for many people.

Because calcium takes up more room in the capsules than the MK4 and vitamin D3, Osteo-K capsules are the largest, Osteo-K Minis are smaller, and Osteo-MK4 capsules are the smallest.

How many daily capsules can you take?

Compliance, which is the ability to take a product as directed on the bottle, is a serious issue. NBI’s customer survey found that 78% of people taking Osteo-K took it every day. The reasons for some people’s non-compliance varied, but a few reported that if there were fewer capsules to take each day, they’d be more likely to take the full daily recommended amount.

If you want fewer capsules daily while still getting the same powerful bone-building benefits as in the original Osteo-K formula, then Osteo-K Minis is for you. But if you don’t mind taking more capsules (6 per day in Osteo-K versus 4 per day in Osteo-K Minis), and you like the idea of getting more calcium in your dietary supplement, then the original Osteo-K formula is the right choice. Our calcium-free version, Osteo-MK4, has the fewest capsules–2 daily.

MK4 Bone Health Research

The benefits of MK4 for bone health have been studied for more than 30 years and published in dozens of medical journals. There are over 25 clinical trials with more than 7,000 people. The research consistently shows that MK4 improves bone health laboratory markers, supports healthy bone structure and maintains strong bones as indicated by significantly fewer fractures.

Strong Bones. Active Life.

MK4 vs MK7 for Bone Health

There are two forms of vitamin K2 commercially available in dietary supplements: MK4 and MK7. While they’re both naturally found in food, your body can create its own MK4. This is not the case for MK7. We can’t make MK7, which is instead only created by bacterial fermentation. Natural MK4 used in NBI’s dietary supplements is derived from Orange Jasmine (Murraya paniculata) leaf geraniol extract.

MK7 has a longer half-life than MK4 and both can promote healthy bone laboratory markers and bone density. MK7, however, has never been shown in clinical trials to reduce fractures. Only MK4 has demonstrated the ability to maintain strong bones as indicated significantly fewer fractures in randomized, controlled clinical trials. 

Why Osteo-K Shatters the Competition


*MK4 is the most researched form of vitamin K2 for bone health. Its health benefits have been studied for more than thirty years. More than 25 clinical trials with over 7000 volunteers indicate that MK4 (45 mg/day) supports healthy bone density and maintains strong bones as indicated by more than 70% fewer fractures. Calcium and vitamin D have been shown to reduce fractures by 18%. MK7 has not been shown to reduce fractures as a primary endpoint in clinical trials. In a clinical trial of vitamin K1 as a dietary supplement, this nutrient did not maintain healthy bone density.

†Oxide minerals. Magnesium oxide is inexpensive and commonly found in vitamin and mineral formulas. People absorb only about 4% of the magnesium as magnesium oxide. This means that 96% of what you put in your mouth is just passing right through you and being eliminated in your stool. In fact, magnesium oxide is so poorly absorbed that it’s used in higher amounts as a laxative.


Cheung AM, Tile L, Lee Y, et al. 2008;5(10):e196. Cockayne S, Adamson J, Lanham-New S, et. al. 2006;166(12):1256-1261. Huang ZB,Wan SL, Lu YJ, et. al. 2015;26(3):1175-1186. Firoz M, Graber M. 2001;14(4):257‐262. Iwamoto J, Takeda T, Ichimura S.2001;6(6):487-492. Larsen ER, Mosekilde L, et. al. 2004;19(3):370- 378. Lindberg JS, Zobitz MM, Poindexter JR et al. 1990;9(1):48‐55. Ma ML, et al. 2022;10:979649. Shiraki M, Shiraki Y, et. al. 2000;15(3):515-522.


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Osteo-K Frequently Asked Questions

General Osteo-K Questions
Q: Does Osteo-K contain MK4?

Yes, plus other important nutrients for bone health. Each six capsules of Osteo-K contain 45 mg of MK4, a form of vitamin K2, 1000 mg calcium (citrate) and 2000 units Vitamin D3.

Q: What is the source of MK4 in your products? 

NBI’s MK4 is derived from Orange Jasmine (Murraya paniculata), leaf geraniol extract.

Q: Who created Osteo-K?

Osteo-K, a bone support dietary supplement, was created by physicians from Harvard, Cornell, MIT and Bastyr. After years of Dr. Steve Pieczenik’s wife taking Fosamax without any benefit, and with painful side effects, he and his partner, Dr. John Neustadt began researching natural ways women and men can promote their bone health.

Q: How is Osteo-K different from other bone support formulas?

Osteo-K is the only osteoporosis supplement that contains the amount (45 mg) and form of vitamin K (MK4) plus calcium and vitamin D shown in clinical trials to prevent fractures.

Q: Is Osteo-K gluten free?

Yes. All of our NBI dietary supplements are completely gluten free.

Q: Are the Osteo-K capsules vegetarian?

Yes. All our capsules are 100% vegetarian cellulose capsules.

Q: Why doesn’t Osteo-K contain strontium?

For several reasons. First, clinical trials show that MK4 decreases fractures better than strontium–81% for MK4 versus 44% for strontium. Second, strontium decreases calcium absorption, and calcium is an important nutrient. Third the form of strontium used in all the clinical trials is strontium ranelate. Currently strontium ranelate is only available in Europe. Strontium in the US is available as strontium citrate, which has never been studied and shown to decrease fractures. Finally, strontium interferes with bone density scans and provides false results. The question of strontium and osteoporosis is a good one, but the research at this time supports MK4 over strontium.

Who should take Osteo-K?
Q: Should I take Osteo-K?

If you are concerned about your bone health, and are not taking Coumadin (warfarin), you should take Osteo-K.

Q: Can everyone take Osteo-K?

No. People taking warfarin (Coumadin) cannot take Osteo-K because the vitamin K in the dietary supplement will interfere with the warfarin.

Osteo-K, Calcium and Your Other Supplements

Q: Does Osteo-K interact with any other dietary supplements?

No. However, if you are taking different dietary supplements that also contain vitamin D and minerals, there is always a risk of taking too much vitamin D and too many minerals at the same time. Taking too many minerals can cause a watery diarrhea, technically called osmotic diarrhea. Simply taking Osteo-K away from other dietary supplements can correct this situation. If taking more than 100 mcg (4000 IU) vitamin D daily. Vitamin D blood level monitoring is recommended.

Q: Does Osteo-K replace my calcium supplement?

Yes. Because Osteo-K combines three of the most important micronutrients needfor bone health into one formd eula it’s the only dietary supplement you need for bone health. You don’t need to buy extra calcium unless advised to do so by your healthcare provider.

Q: Do I need to take extra vitamin D if I’m taking Osteo-K?

Only if your doctor has prescribed higher amounts of vitamin D than what is in Osteo-K. The total daily recommended amount (six capsules total divided into two servings) of Osteo-K contains 2,000 units of vitamin D3.

Osteo-K and Drug Interactions
Q: Will the MK4 in Osteo-K interact with heparin?

No. MK4 does not interact with heparin.

Q: If I’m taking aspirin, can I still take Osteo-K?

Yes. None of the ingredients in Osteo-K, including MK4, interfere with the effects of aspirin.

Q: If I’m taking warfarin (Coumadin), can I still take Osteo-K?

No. Vitamin K, which is in Osteo-K, will interfere with warfarin (Coumadin). Warfarin works to prevent blood clots by blocking how the body uses vitamin K to form blood clots. Taking vitamin K while taking warfarin overrides this mechanism and makes warfarin less effective. People taking warfarin absolutely cannot take Osteo-K.

Q: Can I take Osteo-K with my osteoporosis medication?

Yes. The ingredients in Osteo-K are safe to take with osteoporosis medications.

MK4, Healthy Bones and Bone Strength
Q: Does Osteo-K contain MK4?

Yes. Osteo-K contains the amount of MK4 used in clinical trials, plus calcium and vitamin D3.

Q: What is MK4 and how does it work?

MK4 is a form of vitamin K2 and the principal ingredient in Osteo-K. MK4 works by activating genes involved in promoting bone health through the formation of bone collagen and bone mineralization. These genes include growth differentiation factor 15 (GDF15), Stanniocalcin, Tenascin-c and bone morphogenic protein-2 (BMP-2). Only MK4 has been shown to activate all these genes.

Q: Has MK4 been shown to maintain bone strength?

Yes. In clinical trials MK4 (45 mg/day when taken in divided doses) has been shown to be an important nutrient for bone health. More than 25 clinicals trials with over 7000 volunteers conclude that MK4 (45 mg/day) maintains strong bones.

Q: Is MK4 a drug?

No. MK4 is a naturally occuring form of vitamin K2 and is a dietary supplement. It has not been approved by the FDA to prevent, treat or cure any disease.

Q: Is 45 mg of MK4 safe?

Vitamin K is important for healthy blood clotting. However, taking extra vitamin K does not increase your risk. Studies have shown that taking in excess of even 135 mg/day of MK4 does not increase blood clot risk. That’s because once the body has enough vitamin K for normal clotting, it cannot use more. NOTE: If you are at increased risk of blood clots and are taking warfarin (Coumadin), MK-4 counteracts the intended action of this medication.

Q: How does MK4 compare with MK7?

MK4 and MK7 are forms of vitamin K2. The health benefits of MK4 have been researched for more than thirty years and it’s the most-studied form of vitamin K2 for bone health. Only MK4 has been shown to maintain strong bones; support brain, liver and immune health; and promote healthy bone marrow and blood cell production.

Q: How does MK4 compare with strontium?

MK4 clinical trials compared to strontium clinical trials showed that MK4 had a superior ability to support healthy bones.

Q: Will I maintain strong bones if I take MK4?

Studies show that MK4 can help support strong bones in clinical trials that compared people taking 45 mg per day of MK4 to people not taking MK4.

What is the Best Calcium to Take?

What is the Best Calcium to Take?

There are many types of calcium on the market. There’s calcium carbonate, calcium citrate, coral calcium, calcium citrate-malate, algae calcium, and more. Learn which one the science supports and why you should be taking it.

MK4 or MK7, Which is Better for Bones?

MK4 or MK7, Which is Better for Bones?

MK4 and MK7 are two forms of vitamin K2 commonly found in dietary supplements. Both are naturally occurring, and both have health benefits. But which one is better? When should you take one instead of the other? This article answers these questions so you can make the best possible decision for your health.

Vitamin K for Bone, Brain, Immune and Liver Health

Vitamin K for Bone, Brain, Immune and Liver Health

MK4 is a specific form of vitamin K2. And while MK4 is best known for bone health, it’s an important nutrient used throughout your body. Among all the forms of vitamin K2, only MK4 has been shown to maintain strong bones; support brain, liver, and immune health; and promote healthy bone marrow and blood cell production.

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Studies on MK4 for Maintaining Strong Bones
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