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Dietary supplement

Vitamin K1 100 mcg Ingredients & Drug Interactions

by Swanson

Vitamin K1 100 mcg label
See full label image
Tablet Or Pill Category: Vitamin
Most serious interaction: Major
Clinical methodology reviewed by · Updated Sep 30, 2026 · Label data from the NIH DSLD
What is this page for?

First and foremost: checking Vitamin K1 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

Vitamin K1 100 mcg is a dietary supplement by Swanson 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 K1. Use the checker below to test your specific medication, or read the full HelloPharmacist Interaction Report.

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Check Your Meds Against Vitamin K1 100 mcg by Swanson

Ask about any prescription or over-the-counter medication and we check it for interactions with Vitamin K1 100 mcg by Swanson — and tell you which ingredient is responsible.

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HelloPharmacist Scorecard of Vitamin K1 100 mcg by Swanson

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 Sep 24, 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 contains one active ingredient: vitamin K1 (phylloquinone), a fat-soluble vitamin your body needs to make proteins involved in blood clotting and bone health. The tablet also includes several inactive ingredients — microcrystalline cellulose, stearic acid, croscarmellose sodium, magnesium stearate, silica, hypromellose, and glycerin — which help form and stabilize the tablet.

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.
  • We looked for evidence on: Cardiovascular disease (CVD), Osteoporosis, Hemorrhagic disease, Hypoprothrombinemia, Vitamin K-dependent clotting factors deficiency (VKCFD), Warfarin anticoagulation — and 4 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, Warfarin anticoagulation, Vitamin K-dependent clotting factors deficiency (VKCFD).
  • Also on file: Vitamin K is rated "Possibly Effective" for Osteoporosis.

Vitamin K1 is established as effective for treating vitamin K deficiency bleeding and conditions tied to low levels of vitamin K-dependent clotting factors, and it's also effective for managing warfarin overdose. For osteoporosis, the evidence is possibly effective — meaning there's some promise, but it's not yet conclusive.

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 K1 is generally well tolerated in healthy people at typical supplement doses. The most common side effects are mild: nausea, diarrhea, stomach upset, and abdominal pain.

Vitamin K1 is rated likely safe during pregnancy and breastfeeding. That said, if you're thinking about taking a supplement — rather than just eating vitamin K-rich foods — talk it over with your doctor or pharmacist first, especially if you have any health conditions or take medications.

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.

Blood thinners — especially warfarin (Coumadin) — are the main ones to check. Vitamin K directly opposes warfarin's effect, so consistency matters.

Before you add this supplement, clear it with your doctor or pharmacist and make sure they know about any anticoagulants you're taking.

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.

Vitamin K1 is useful if you have a diagnosed vitamin K deficiency or your doctor recommends it for bone health. If you take warfarin or any other blood thinner, you'll need your doctor's approval and close monitoring, because this supplement can interfere with how your medication works.

Check with your own doctor or pharmacist before starting, stopping, or changing how much you take.

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 Mar 22, 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 Vitamin K1 100 mcg, straight from the product label.

Brand Swanson
Barcode (UPC) 087614019949
Net contents 100 Tablet(s)
Market status On market
Date entered into DSLD Mar 22, 2024
DSLD ID 308812
Product type Vitamin
Supplement form Tablet Or Pill
Dietary claims / uses Nutrient, All Other, Structure/Function
Intended target group(s) Adult (18 - 50 Years)
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 Vitamin K1 100 mcg by Swanson, 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 Tablet(s)
Maximum serving Sizes:
1 Tablet(s)
Servings per container
100
UPC/BARCODE
087614019949
IngredientAmount% DV
Vitamin K1100 mcg83%

Other ingredients: Microcrystalline Cellulose, Stearic Acid, Croscarmellose Sodium, Magnesium Stearate, Silica, Hypromellose, Glycerin

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.
General Statements

Visit our website at www.swanson.com

Suggested/Recommended/Usage/Directions

Suggested use: For adults only. Keep out of reach of children.

Precautions

Consult your healthcare provider before using this or any product if you are pregnant or nursing, taking medication, especially blood-thinning medication, or have a medical condition.

Do not use if seal is broken.

Storage

Store in a cool, dry place.

FDA Disclaimer Statement

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

Formula

Vitamin K1 100 mcg per tablet

Formulation

Bone and cardiovascular health

FDA Statement of Identity

Vitamin Supplement

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

See for yourself

Vitamin K1 100 mcg by Swanson label

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

Vitamin K1 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 Vitamin K1 100 mcg by Swanson

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

Serving size1 Tablet(s) Dosage formTablet Or Pill Servings per container100 Amounts shown are per serving.

Vitamin K1

Interacts with
2 drugs
100 mcg per serving Form: Phylloquinone

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 K1 monograph & interactions

Other (inactive) ingredients: Microcrystalline Cellulose, Stearic Acid, Croscarmellose Sodium, Magnesium Stearate, Silica, Hypromellose, Glycerin. These complete the product’s ingredient list but are not active constituents.

Interaction report

Vitamin K1 100 mcg by Swanson Drug Interactions

Want to check YOUR meds against Vitamin K1 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 K1 2

Individual Drug Interactions

The ingredients in Vitamin K1 100 mcg interact with 2 drugs. Click any drug to see the details.

1 of the 1 ingredient in Vitamin K1 100 mcg interact with drugs. Each result below shows which ingredient is responsible. Vitamin K1

Each ingredient & the kinds of drugs it affects

For each ingredient in Vitamin K1 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 K11 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 K1 full monograph & interactions
The maker

Brand information

Manufacturer and brand details for Vitamin K1 100 mcg, from the product label.

Swanson

See all Swanson products
Name
Swanson Health Products
City
Fargo
State
ND
ZipCode
58104
Phone Number
1-800-437-4148
Web Address
swanson.com
Pharmacist Counseling Corner

Vitamin K1 100 mcg by Swanson: Common Questions

Does Vitamin K1 100 mcg by Swanson interact with any medications?
Yes. Based on its ingredients, Vitamin K1 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?
Vitamin K1 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 this if I'm on warfarin?
Not without talking to your doctor first. Vitamin K can reduce how well warfarin works to prevent blood clots. Your doctor may allow it, but you'll need monitoring, and you'll need to keep your vitamin K intake steady — no big changes from food or supplements. Check with your own doctor or pharmacist before you start.
What are the side effects?
Taken by mouth, vitamin K is generally well tolerated. The most common side effects are mild and gastrointestinal — nausea, diarrhea, stomach upset, and abdominal pain. Serious reactions are very rare.
Is it safe during pregnancy and breastfeeding?
Yes — vitamin K1 is rated likely safe during pregnancy and lactation. If you're pregnant or nursing and considering a supplement, it's still a good idea to mention it to your doctor or midwife.
What is vitamin K1 used for?
It treats vitamin K deficiency and related bleeding disorders, and it's effective for managing warfarin overdose. There's also some evidence it may help with osteoporosis, though that's not yet conclusive.
Do I need a supplement, or can I get enough from food?
Most healthy people get plenty of vitamin K from leafy greens, cruciferous vegetables, and other foods. Supplements are usually recommended only if you have a diagnosed deficiency or your doctor advises it. Talk with your doctor or pharmacist about whether you need one.

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

Not sure if Vitamin K1 100 mcg is safe with your meds?

Our pharmacists answer your medication & supplement questions — free.

Ask a pharmacist

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.

Vitamin K1 100 mcg label
Go deeper

The Full Monographs Behind Vitamin K1 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

Vitamin K1 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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