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Dietary supplement

K2 MK-7 100 mcg Ingredients & Drug Interactions

by 21st Century

K2 MK-7 100 mcg label
See full label image
Capsule Category: Vitamin
Most serious interaction: Major
Clinical methodology reviewed by · Updated Sep 16, 2026 · Label data from the NIH DSLD
What is this page for?

First and foremost: checking K2 MK-7 100 mcg against your medications. The heart of this page is the interaction checker and the full interaction report — how this product’s ingredients may interact with prescription and over-the-counter medicines you may be taking.

Around that, we add a pharmacist’s high-level view of the product as a whole — what’s inside, the evidence for its stated use, how transparent the label is, and what safety data exists — so you can see the full picture in one place. It’s educational information from our licensed clinical databases and the clinical staff at HelloPharmacist — not medical advice — and we don’t sell or endorse products. Our editorial policy

The interaction bottom line Most serious interaction: Major

K2 MK-7 100 mcg is a dietary supplement by 21st Century with 1 active ingredient. Its ingredients are commonly taken for supporting normal blood clotting, bone health, heart and vascular health.Based on those ingredients, 2 medications have a known interaction with it, the most serious rated major. The ingredients most likely to interact are Vitamin K2. Use the checker below to test your specific medication, or read the full HelloPharmacist Interaction Report.

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Check Your Meds Against K2 MK-7 100 mcg by 21st Century

Ask about any prescription or over-the-counter medication and we check it for interactions with K2 MK-7 100 mcg by 21st Century — and tell you which ingredient is responsible.

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HelloPharmacist Scorecard of K2 MK-7 100 mcg by 21st Century

Our pharmacy team’s full take, with four database checks built into the cards below — a summary of what is known, not a grade of the product itself.

From our pharmacy team — supplement deep dive

Generated from HelloPharmacist’s pharmacist-curated databases and editorial rules · Last generated Jul 11, 2026

What’s inside

Full disclosure
Ingredient Transparency · database check
Full

Every active ingredient lists its own amount on the label.

Why this rating?
  • The label discloses an exact amount for 1 of its 1 active ingredient.
  • No proprietary blends here — you can verify the dose of every single component.

This product has one active ingredient: Vitamin K2 (MK-7 form) at 100 mcg per capsule. Vitamin K is a fat-soluble vitamin that your body needs for blood clotting and bone health.

The capsule also contains inactive ingredients — cellulose, oat fiber, dicalcium phosphate, magnesium silicate, magnesium stearate, and silicon dioxide — which are fillers and binders that hold the supplement together.

Does it work?

Strong evidence
Evidence for Intended Use · database check
By FDA rules, dietary supplements can’t claim to treat, cure, or prevent disease — so labels speak in careful marketing language. We discern each product’s intended use from its name, label claims, and label statements, then grade the clinical evidence for that use. How these ratings are computed
Strong

Clinical evidence supports at least one of this product's ingredients for its stated purpose.

Why this rating?
  • The label markets this product for: bone and cardiovascular health support.
  • We looked for evidence on: Cardiovascular disease (CVD), Osteoporosis, Hemorrhagic disease, Hypoprothrombinemia, Vitamin K-dependent clotting factors deficiency (VKCFD), bone mineralization — and 2 related terms.
  • The strongest evidence on file: Vitamin K is rated "Effective" for Hemorrhagic disease (Natural Medicines).
  • Also on file: Vitamin K is rated "Effective" for Hypoprothrombinemia, Vitamin K-dependent clotting factors deficiency (VKCFD).
  • Also on file: Vitamin K is rated "Possibly Effective" for Osteoporosis.

Vitamin K2 is effective for treating vitamin K deficiency conditions, including hypoprothrombinemia (a blood-clotting problem), vitamin K-dependent clotting factor deficiency, and hemorrhagic disease (bleeding disorders). It's also effective for managing warfarin anticoagulation when doses are coordinated with your doctor.

For bone health and osteoporosis, the evidence shows it's possibly effective, meaning the data suggests a benefit but more research is needed to be certain.

The evidence, ingredient by ingredient Vitamin K

How safe is it?

Well-documented data
Safety Information · database check
Well characterized

Adverse-effect, pregnancy, and general safety data are on file for most of these ingredients.

Why this rating?
  • We hold adverse-effect (side-effect) data for 1 of the 1 matched ingredient.
  • Pregnancy & breastfeeding safety ratings cover 1 of 1.
  • General safety write-ups exist for 1 of 1.
  • Remember: this measures how much safety information exists. Thin data is not the same as being safe.

Taken by mouth, vitamin K2 is generally well tolerated in healthy people at normal doses. The most common side effects are mild: nausea, diarrhea, stomach upset, and abdominal pain.

These effects tend to be mild to moderate. The safety data advises checking with your doctor before taking supplements, especially if you have any health conditions.

Vitamin K2 is rated likely safe during pregnancy and breastfeeding.

Side effects, ingredient by ingredient Vitamin K

Meds to double-check

Major interaction found
Known Interaction Concern · database check
Major identified

At least one ingredient has a documented Major-severity interaction. Check your medications for a personalized result.

Why this rating?
  • 1 of the 1 matched ingredient can interact with medications — Vitamin K.
  • The most serious interaction on file is rated Major.
  • Some involve high-stakes drug classes: anticoagulant / antiplatelet drugs.
  • For scale: 2 individual medications appear in the full list. A big number alone doesn't make a product dangerous — what matters is whether YOUR medication is on it, so run yours through the interaction checker on this page.

Before taking this product, check with your pharmacist or doctor if you take warfarin (Coumadin) or any other blood thinner. Vitamin K2 can reduce the blood-thinning effect and increase your clot risk.

This is a Major interaction and needs medical oversight.

Check your own medication Run your meds through the checker above

The bottom line

Scorecard at a glanceFully disclosed formula with clinical evidence supporting its stated purpose. Major medication interactions have been identified, and safety information is well characterized.

K2 MK-7 is a straightforward supplement for supporting bone and clotting health — but it's not for everyone. If you take warfarin or any blood thinner, you must talk to your doctor before starting it.

Anyone else in good health can consider it, but a quick conversation with your pharmacist or doctor about your other medications is smart.

Educational only — not medical advice; always confirm with your pharmacist. Our editorial policy · How we use AI

Assessment coverage: 1 of 1 active ingredient matched to our full ingredient reviews (monographs). Based on the product label dated Jan 24, 2024.

This Scorecard evaluates available label information, ingredient evidence, and known medication-safety considerations. It does not independently verify product identity, purity, potency, contamination, or manufacturing quality. How these ratings are computed

At a glance

General information

Key facts about K2 MK-7 100 mcg, straight from the product label.

Brand 21st Century
Barcode (UPC) 740985280676
Net contents 110 Vegetarian Capsule(s)
Market status On market
Date entered into DSLD Jan 24, 2024
DSLD ID 304109
Product type Vitamin
Supplement form Capsule
Dietary claims / uses Nutrient, All Other, Structure/Function
Intended target group(s) Vegan, Vegetarian, Adult (18 - 50 Years), Gluten Free, Dairy Free
From the label
Everything in this section is reproduced from the manufacturer’s own product label — it’s the label speaking, not HelloPharmacist. We show it so you can see exactly what the maker states; we don’t verify or endorse those statements.

Supplement Facts

The label details for K2 MK-7 100 mcg by 21st Century, sourced from the NIH Dietary Supplement Label Database.

Supplement Facts

Daily Value (DV) Target Group(s):
Adults and children 4 or more years of age
Minimum serving Sizes:
1 Vegetarian Capsule(s)
Maximum serving Sizes:
1 Vegetarian Capsule(s)
Servings per container
110
UPC/BARCODE
740985280676
IngredientAmount% DV
Vitamin K2100 mcg--

Other ingredients: Cellulose, Oat Fiber, Dicalcium Phosphate, Magnesium Silicate, Magnesium Stearate, Silicon Dioxide

Tap any ingredient to jump to its full detail below.

Label statements
These statements are the manufacturer’s wording, reproduced from the product label — the label is saying it, not HelloPharmacist. We don’t verify or endorse them.
Suggested/Recommended/Usage/Directions

Directions: As a vitamin supplement, adults take one (1) capsule daily with any meal or as directed by a healthcare provider. Do not exceed recommended dosage. Individual results may vary.

Precautions

Do not exceed recommended dosage.

Warning: Consult a healthcare provider prior to use if pregnant, nursing, on medications, especially anti-coagulants, have a medical condition or are planning a medical procedure.

Stop use and contact a physician if adverse reactions occur. Do not use if product appears to be tampered with or seal is broken.

Keep out of reach of children.

Contains less than 2% of: Silicon Dioxide.

Storage

Store at room temperature.

FDA Disclaimer Statement

These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.

General Statements

New

Formulation

Bone health & cardiovascular support

Gluten free Non-GMO

Guaranteed quality laboratory tested Trusted quality for over 30 years

No added sugar, salt, yeast, artificial flavors or colors.

Suitable for vegans.

FDA Statement of Identity

Vitamin Supplement

Formula

Vitamin K2, the most active form of vitamin K, supports the formation of healthy bones and cardiovascular health.

Is this label outdated? Report a formula or label change and our pharmacy team will review it.

See for yourself

K2 MK-7 100 mcg by 21st Century label

The label scan from the NIH Dietary Supplement Label Database. Tap to enlarge.

K2 MK-7 100 mcg label

Label images are published by the NIH Dietary Supplement Label Database for the version of this product on file. Always read your actual product label.

View the full label (PDF)
What’s inside

The Ingredients in K2 MK-7 100 mcg by 21st Century

This is the 1 active ingredient this product is made of. Select it to open its full monograph.

Serving size1 Vegetarian Capsule(s) Dosage formCapsule Servings per container110 Amounts shown are per serving.

Vitamin K2

Interacts with
2 drugs
100 mcg per serving Form: Menaquinone-7

Vitamin K is an essential nutrient your body needs for normal blood clotting and to support healthy bones. Most people get enough from food, but suppl...

Vitamin K2 monograph & interactions

Other (inactive) ingredients: Cellulose, Oat Fiber, Dicalcium Phosphate, Magnesium Silicate, Magnesium Stearate, Silicon Dioxide. These complete the product’s ingredient list but are not active constituents.

Interaction report

K2 MK-7 100 mcg by 21st Century Drug Interactions

Want to check YOUR meds against K2 MK-7 100 mcg?

Ask about interactions with your drugs in plain English — “Can I take it with lisinopril?” — and we find you the answer in seconds, ingredient by ingredient.

 Go to the checker
2Drugs
2 Major

Ingredients driving the most interactions

Vitamin K2 2

Individual Drug Interactions

The ingredients in K2 MK-7 100 mcg interact with 2 drugs. Click any drug to see the details.

1 of the 1 ingredient in K2 MK-7 100 mcg interact with drugs. Each result below shows which ingredient is responsible. Vitamin K2

Each ingredient & the kinds of drugs it affects

For each ingredient in K2 MK-7 100 mcg with known interactions, here are the types of medications it can affect. Open any type for the detail — or search your exact drug in the checker above.

Vitamin K21 drug type · 2 drugs

Warfarin (Coumadin)

Vitamin K can antagonize and reverse the therapeutic effects of warfarin.
Vitamin K antagonizes the effects of warfarin. Excessive vitamin K intake, either from supplements or from changes in the diet, can reduce the anticoagulant effect of warfarin.

Likelihood Likely Evidence C
Vitamin K2 full monograph & interactions
The maker

Brand information

Manufacturer and brand details for K2 MK-7 100 mcg, from the product label.

21st Century

See all 21st Century products
Name
21st Century HealthCare, Inc.
Street Address
2119 S. Wilson St.
City
Tempe
State
AZ
ZipCode
85282
Web Address
21stcenturyvitamins.com
Pharmacist Counseling Corner

K2 MK-7 100 mcg by 21st Century: Common Questions

Does K2 MK-7 100 mcg by 21st Century interact with any medications?
Yes. Based on its ingredients, K2 MK-7 100 mcg has a known interaction with 2 medications, including 2 rated major. Use the checker to see how it interacts with a specific drug.
How can one product interact with so many drugs?
K2 MK-7 100 mcg contains a single active ingredient, and that one ingredient can interact with many different medications on its own. We check it against each medication and show the mechanism responsible.
Where does this information come from?
The product label data comes from the NIH Dietary Supplement Label Database (DSLD); the interaction data is built on the Natural Medicines database and reviewed by HelloPharmacist pharmacists.
Can I take K2 if I'm on warfarin?
Not without talking to your doctor first. Vitamin K2 directly opposes how warfarin works and can make it less effective at preventing clots. Your doctor may need to adjust your warfarin dose or watch your blood work more closely if you want to take K2.
What are the side effects of this supplement?
When taken by mouth, the most common side effects are nausea, diarrhea, stomach upset, and abdominal pain. These tend to be mild to moderate and fairly uncommon. Serious side effects are rare.
Is this K2 effective for bone health?
The evidence shows vitamin K2 is possibly effective for osteoporosis — meaning it may help, but we need more research to be sure. It's definitely effective for treating true vitamin K deficiency and blood-clotting disorders.
Is it safe to take during pregnancy or breastfeeding?
Yes — vitamin K2 is rated likely safe during pregnancy and lactation. If you're pregnant or nursing and thinking about taking it, a quick check with your doctor or midwife is still a good idea.
Do I need to worry about the fillers in this capsule?
No. The inactive ingredients — cellulose, oat fiber, dicalcium phosphate, and the others — are standard binders and fillers used in most supplements to hold the capsule together. They're inert and don't affect how the supplement works.

Written and reviewed by the HelloPharmacist editorial staff. Our editorial policy

Not sure if K2 MK-7 100 mcg is safe with your meds?

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Label information is sourced from the NIH Dietary Supplement Label Database and reflects the product version on file; always read your actual product label. This page is for education only and is not a substitute for professional medical advice. Confirm with your pharmacist or doctor before combining supplements and medications.

K2 MK-7 100 mcg label
Go deeper

The Full Monographs Behind K2 MK-7 100 mcg’s Ingredients

Every ingredient we hold a full HelloPharmacist monograph for — uses, evidence, safety, and the complete interaction list.

Herb & supplement monograph

Vitamin K

Interacts with 2 drugs

Vitamin K is an essential nutrient your body needs for normal blood clotting and to support healthy bones. Most people get enough from food, but supplements are sometimes used for deficiency...

Read the full Vitamin K monograph →
Sources

Sources & How We Checked

K2 MK-7 100 mcg's label data comes from the NIH Dietary Supplement Label Database; the ingredient interaction data is from the Natural Medicines database, reviewed by our pharmacists.

Content is written and reviewed by licensed HelloPharmacist pharmacists. See our data sources and editorial standards for how this information is built and checked.

The 11 references behind this product’s interaction data

Every citation that drives the interaction findings for this product’s ingredients, from the evidence-graded Natural Medicines (TRC Healthcare) database. Open an ingredient to browse its citations — links open the study on PubMed or the publisher’s site.

Vitamin K 11 references
  1. McEvoy GK, ed. AHFS Drug Information. Bethesda, MD: American Society of Health-System Pharmacists, 1998.
  2. Food and Nutrition Board, Institute of Medicine. Dietary Reference Intakes for Vitamin A, Vitamin K, Arsenic, Boron, Chromium, Copper, Iodine, Iron, Manganese, Molybdenum, Nickel, Silicon, Vanadium, and Zinc. Washington, DC: National Academy Press, 2002.
  3. Crowther MA, Ageno W, Garcia D, et al. Oral vitamin K versus placebo to correct excessive anticoagulation in patients receiving warfarin: a randomized trial. Ann Intern Med. 2009;150(5):293-300. PubMed
  4. Dietary vitamin K guidance: an effective strategy for stable control of oral anticoagulation? Nutr Rev. 2010;68(3):178-81. PubMed
  5. Kim JS, Nafziger AN, Gaedigk A, et al. Effects of oral vitamin K on S- and R-warfarin pharmacokinetics and pharmacodynamics: enhanced safety of warfarin as a CYP2C9 probe. J Clin Pharmacol. 2001 Jul;41(7):715-22. PubMed
  6. Riegert-Johnson, D. L. and Volcheck, G. W. The incidence of anaphylaxis following intravenous phytonadione (vitamin K1): a 5-year retrospective review. Ann.Allergy Asthma Immunol. 2002;89(4):400-406. PubMed
  7. Dezee, K. J., Shimeall, W. T., Douglas, K. M., Shumway, N. M., and O'malley, P. G. Treatment of excessive anticoagulation with phytonadione (vitamin K): a meta-analysis. Arch.Intern.Med. 2-27-2006;166(4):391-397. DOI
  8. Dentali, F., Ageno, W., and Crowther, M. Treatment of coumarin-associated coagulopathy: a systematic review and proposed treatment algorithms. J.Thromb.Haemost. 2006;4(9):1853-1863. PubMed
  9. Caluwé R, Vandecasteele S, Van Vlem B, Vermeer C, De Vriese AS. Vitamin K2 supplementation in haemodialysis patients: a randomized dose-finding study. Nephrol Dial Transplant. 2014;29(7):1385-90.
  10. Huang ZB, Wan SL, Lu YJ, Ning L, Liu C, Fan SW. Does vitamin K2 play a role in the prevention and treatment of osteoporosis for postmenopausal women: a meta-analysis of randomized controlled trials. Osteoporos Int. 2015;26(3):1175-86. PubMed
  11. Hunnali CR, Devi U, Kitchanan S, Sethuraman G. Three Different Regimens for Vitamin K Birth Prophylaxis in Infants Born Preterm: A Randomized Clinical Trial. J Pediatr 2023;255:98-104. PubMed

See these in context on the Vitamin K monograph →

Parts of this content are provided by the Therapeutic Research Center, LLC.

DISCLAIMER: Currently this does not check for drug-drug interactions. This is not an all-inclusive comprehensive list of potential interactions and is for informational purposes only. Not all interactions are known or well-reported in the scientific literature, and new interactions are continually being reported. Input is needed from a qualified healthcare provider including a pharmacist before starting any therapy. Application of clinical judgment is necessary.

© 2021 Therapeutic Research Center, LLC

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