Vitamin K-2 Ingredients & Drug Interactions
What is this page for?
First and foremost: checking Vitamin K-2 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
Vitamin K-2 is a dietary supplement by U.S. Longevity Institute with 2 active ingredients. Its ingredients are commonly taken for supporting normal blood clotting, bone health, heart and vascular health.Based on those ingredients, 583 medications have a known interaction with it, the most serious rated major. The ingredients most likely to interact are Alfalfa powder, Vitamin K2. Use the checker below to test your specific medication, or read the full HelloPharmacist Interaction Report.
Check Your Meds Against Vitamin K-2 by U.S. Longevity Institute
Ask about any prescription or over-the-counter medication and we check it for interactions with Vitamin K-2 by U.S. Longevity Institute — and tell you which ingredient is responsible.
AI summaries are generated from our interaction database for education only — always confirm with your pharmacist. How we use AI
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HelloPharmacist Scorecard of Vitamin K-2 by U.S. Longevity Institute
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.
What’s inside
Full disclosure
This product contains two active ingredients: vitamin K2 and alfalfa powder. Vitamin K2 plays a key role in blood clotting and bone health.
Alfalfa is a plant-based ingredient traditionally used in herbal medicine. The product also includes inactive ingredients — cellulose, ascorbyl palmitate, rice flour, and silica — which are fillers and capsule materials.
Does it work?
Strong evidence
Vitamin K2 is effective for treating vitamin K deficiency conditions, including hypoprothrombinemia (low clotting proteins), vitamin K-dependent clotting factor deficiency, reversing warfarin overtreatment, and hemorrhagic disease. It is possibly effective for osteoporosis.
Alfalfa has insufficient reliable evidence to support its use for diabetes, indigestion, high cholesterol, or menopausal symptoms — the evidence we hold doesn't establish it as effective for any of these.
How safe is it?
Well-documented data
Vitamin K2 taken by mouth is generally well tolerated. The most common side effects are mild — diarrhea, nausea, and stomach upset.
The facts note it is likely safe in pregnancy and lactation. Alfalfa is generally considered food-safe in small amounts, but supplement doses carry real risks.
The safety data advises against alfalfa in pregnancy because of its estrogen-like activity. During breastfeeding, there isn't enough reliable safety data, so it's best to avoid supplement amounts.
Common side effects from alfalfa include abdominal discomfort, diarrhea, flatulence, and increased stool frequency. Rare serious effects include a lupus-like syndrome with chronic use and dermatitis in sensitive individuals.
Meds to double-check
Major interaction found
Before taking this product, check with your doctor or pharmacist if you take warfarin or any blood thinner — vitamin K2 and alfalfa can reduce its effectiveness. Also double-check if you're on birth control pills, hormone therapy, diabetes medications, immunosuppressants, or photosensitizing drugs.
The alfalfa ingredient may interfere with how these work.
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 K-2 may be right for you if your doctor has identified a vitamin K deficiency or if you're interested in bone health support and don't take warfarin or the other medications listed above. If you take warfarin, any blood thinner, birth control, hormone therapy, diabetes medication, immunosuppressants, or drugs that increase sun sensitivity, talk with your doctor or pharmacist before starting — this product may affect how those medications work.
Even if you're not on any of these, a quick conversation with your own healthcare provider is a smart move before you start.
Educational only — not medical advice; always confirm with your pharmacist. Our editorial policy · How we use AI
Assessment coverage: 2 of 2 active ingredients matched to our full ingredient reviews (monographs). Based on the product label dated Jun 24, 2020.
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
General information
Key facts about Vitamin K-2, straight from the product label.
| Brand | U.S. Longevity Institute |
|---|---|
| Net contents | 100 Veg Capsule(s) |
| Market status | On market |
| Date entered into DSLD | Jun 24, 2020 |
| DSLD ID | 228454 |
| Product type | Botanical With Nutrients |
| Supplement form | Capsule |
| Dietary claims / uses | Nutrient, All Other, Structure/Function |
| Intended target group(s) | Adult (18 - 50 Years), Women (not pregnant or lactating), Gluten Free, Dairy Free |
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 K-2 by U.S. Longevity Institute, sourced from the NIH Dietary Supplement Label Database.
Supplement Facts
| Ingredient | Amount | % DV |
|---|---|---|
| Vitamin K2 | 100 mcg | 83% |
| Alfalfa powder | 250 mg | -- |
Other ingredients: Cellulose, Ascorbyl Palmitate, Rice Flour, Silica
Tap any ingredient to jump to its full detail below.
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
Suggested usage: Take 1 capsule daily with a meal.
Formula
Although Vitamin K is historically known for its role in normal blood clotting function, we now know that Vitamin K is also essential to bone, cardiovascular, and nervous system health. As a biologically active form of Vitamin K, K-2 is important for the formation of healthy, strong bone matrix. Vitamin K's role in arterial health revolves around its ability to support proper calcium metabolism in vascular structures.
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.
Precautions
Caution: For adults only.
Do not use if pregnant, nursing or allergic or contraindicated to aspirin. consult physician if taking medication (especially blood thinners such as warfarin, Coumadin, heparin and aspirin) or have a medical condition.
Discontinue use two weeks prior to surgery or if stomach upset occurs.
Keep out of reach of children.
Do not eat freshness packet. Keep in bottle.
Not manufactured with wheat, gluten, soy, milk, egg, fish, shellfish or tree nut ingredients. Produced in a GMP facility that processes other ingredients containing these allergens.
Formulation
Supports bone health Supports proper calcium metabolism
Not manufactured with wheat, gluten, soy, milk, egg, fish, shellfish or tree nut ingredients.
Natural color variation may occur in this product.
Non-GMO
FDA Statement of Identity
Dietary Supplement
Storage
Store in a cool, dry place after opening.
Is this label outdated? Report a formula or label change and our pharmacy team will review it.
Vitamin K-2 by U.S. Longevity Institute label
The label scan from the NIH Dietary Supplement Label Database. Tap to enlarge.
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)The Ingredients in Vitamin K-2 by U.S. Longevity Institute
These are the 2 active ingredients this product is made of. Select any to open its full monograph.
Serving size1 Vegetarian Capsule(s) Dosage formCapsule Amounts shown are per serving.
Most supplement products combine several ingredients, and a medication can interact with the product through any one of them. Each ingredient below shows whether it has known drug interactions.
Vitamin K2
Interacts with2 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 suppl...
Vitamin K2 monograph & interactionsAlfalfa powder
Interacts with583 drugs
Alfalfa is a nutrient-rich legume that people use for high cholesterol, menopause symptoms, and general wellness, but solid human evidence for most of...
Alfalfa powder monograph & interactionsOther (inactive) ingredients: Cellulose, Ascorbyl Palmitate, Rice Flour, Silica. These complete the product’s ingredient list but are not active constituents.
Vitamin K-2 by U.S. Longevity Institute Drug Interactions
HelloPharmacist Interaction Report
Vitamin K-2 by U.S.
Longevity Institute interacts with several medication types through its vitamin K2 and alfalfa powder content. The most serious concern is with warfarin (Coumadin), a blood thinner — both ingredients can reduce warfarin's ability to prevent clotting, which could raise your stroke or clot risk significantly.
Read the full breakdown — every affected drug type, severity by severity
Alfalfa adds several other interactions to watch for. It may reduce how well birth control pills and hormone therapy work because of its estrogen-like compounds.
It can also theoretically increase the blood-sugar-lowering effect of diabetes medications, raising the risk of low blood sugar (hypoglycemia). Additionally, alfalfa may increase sensitivity to sunlight (photosensitivity) if you're on photosensitizing drugs, and it may interfere with immunosuppressant medications used after transplants or for certain autoimmune conditions.
Vitamin K2 has no other documented interactions beyond warfarin. Altogether, these interactions span 583 individual medications.
If you take any of these drug types — especially warfarin — check your exact medications with the search tool on this page before starting.
Check your own medications below · Editorial policy · How we use AI
Want to check YOUR meds against Vitamin K-2?
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 checkerIngredients driving the most interactions
Individual Drug Interactions
The ingredients in Vitamin K-2 interact with 583 drugs. Click any drug to see the details.
2 of the 2 ingredients in Vitamin K-2 interact with drugs. Each result below shows which ingredient is responsible. Alfalfa powder Vitamin K2
Birth Control PillsBirth control pills
How Birth Control Pills interacts with Vitamin K-2 — through 1 ingredient. Tap an ingredient for the detail:
Alfalfa PowderContraceptive Drugs Moderate
Interaction Summary
Theoretically, alfalfa might interfere with the activity of contraceptive drugs.
Read the full Alfalfa Powder + Birth Control Pills interactionBismuth Subsalicylate, Metronidazole, TetracyclineHelidac
How Bismuth Subsalicylate, Metronidazole, Tetracycline interacts with Vitamin K-2 — through 1 ingredient. Tap an ingredient for the detail:
Alfalfa PowderPhotosensitizing Drugs Moderate
Interaction Summary
Theoretically, concomitant use of alfalfa with photosensitizing drugs might have additive effects.
Read the full Alfalfa Powder + Bismuth Subsalicylate, Metronidazole, Tetracycline interactionBisoprolol, HydrochlorothiazideZiac
How Bisoprolol, Hydrochlorothiazide interacts with Vitamin K-2 — through 1 ingredient. Tap an ingredient for the detail:
Alfalfa PowderPhotosensitizing Drugs Moderate
Interaction Summary
Theoretically, concomitant use of alfalfa with photosensitizing drugs might have additive effects.
Read the full Alfalfa Powder + Bisoprolol, Hydrochlorothiazide interactionBromodiphenhydramineAmbodryl
How Bromodiphenhydramine interacts with Vitamin K-2 — through 1 ingredient. Tap an ingredient for the detail:
Alfalfa PowderPhotosensitizing Drugs Moderate
Interaction Summary
Theoretically, concomitant use of alfalfa with photosensitizing drugs might have additive effects.
Read the full Alfalfa Powder + Bromodiphenhydramine interactionBrompheniramineDimetane, Lodrane
How Brompheniramine interacts with Vitamin K-2 — through 1 ingredient. Tap an ingredient for the detail:
Alfalfa PowderPhotosensitizing Drugs Moderate
Interaction Summary
Theoretically, concomitant use of alfalfa with photosensitizing drugs might have additive effects.
Read the full Alfalfa Powder + Brompheniramine interactionBrompheniramine, Dextromethorphan, PhenylephrineDimetapp DM
How Brompheniramine, Dextromethorphan, Phenylephrine interacts with Vitamin K-2 — through 1 ingredient. Tap an ingredient for the detail:
Alfalfa PowderPhotosensitizing Drugs Moderate
Interaction Summary
Theoretically, concomitant use of alfalfa with photosensitizing drugs might have additive effects.
Read the full Alfalfa Powder + Brompheniramine, Dextromethorphan, Phenylephrine interactionBrompheniramine, Phenylephrine, PhenylpropanolamineDime Time, Normatane TD
How Brompheniramine, Phenylephrine, Phenylpropanolamine interacts with Vitamin K-2 — through 1 ingredient. Tap an ingredient for the detail:
Alfalfa PowderPhotosensitizing Drugs Moderate
Interaction Summary
Theoretically, concomitant use of alfalfa with photosensitizing drugs might have additive effects.
Read the full Alfalfa Powder + Brompheniramine, Phenylephrine, Phenylpropanolamine interactionBrompheniramine, Phenylephrine, PhenyltoloxamineAtrohist Sprinkle
How Brompheniramine, Phenylephrine, Phenyltoloxamine interacts with Vitamin K-2 — through 1 ingredient. Tap an ingredient for the detail:
Alfalfa PowderPhotosensitizing Drugs Moderate
Interaction Summary
Theoretically, concomitant use of alfalfa with photosensitizing drugs might have additive effects.
Read the full Alfalfa Powder + Brompheniramine, Phenylephrine, Phenyltoloxamine interactionBrompheniramine, PhenylpropanolamineDimetapp, E N T, Porcupine
How Brompheniramine, Phenylpropanolamine interacts with Vitamin K-2 — through 1 ingredient. Tap an ingredient for the detail:
Alfalfa PowderPhotosensitizing Drugs Moderate
Interaction Summary
Theoretically, concomitant use of alfalfa with photosensitizing drugs might have additive effects.
Read the full Alfalfa Powder + Brompheniramine, Phenylpropanolamine interactionBrompheniramine, PseudoephedrineAllent, BPM PSEH 08, Bromfed, Bromfed PD, Bromfenex, Bromfenex PD +12 more
How Brompheniramine, Pseudoephedrine interacts with Vitamin K-2 — through 1 ingredient. Tap an ingredient for the detail:
Alfalfa PowderPhotosensitizing Drugs Moderate
Interaction Summary
Theoretically, concomitant use of alfalfa with photosensitizing drugs might have additive effects.
Read the full Alfalfa Powder + Brompheniramine, Pseudoephedrine interactionBumetanideBurinex
How Bumetanide interacts with Vitamin K-2 — through 1 ingredient. Tap an ingredient for the detail:
Alfalfa PowderPhotosensitizing Drugs Moderate
Interaction Summary
Theoretically, concomitant use of alfalfa with photosensitizing drugs might have additive effects.
Read the full Alfalfa Powder + Bumetanide interactionBumetanide, PotassiumBurinex K
How Bumetanide, Potassium interacts with Vitamin K-2 — through 1 ingredient. Tap an ingredient for the detail:
Alfalfa PowderPhotosensitizing Drugs Moderate
Interaction Summary
Theoretically, concomitant use of alfalfa with photosensitizing drugs might have additive effects.
Read the full Alfalfa Powder + Bumetanide, Potassium interactionBupivacaine, MeloxicamZynrelef Kit
How Bupivacaine, Meloxicam interacts with Vitamin K-2 — through 1 ingredient. Tap an ingredient for the detail:
Alfalfa PowderPhotosensitizing Drugs Moderate
Interaction Summary
Theoretically, concomitant use of alfalfa with photosensitizing drugs might have additive effects.
Read the full Alfalfa Powder + Bupivacaine, Meloxicam interactionCaffeine, Diphenhydramine, Ergotamine (prescription Drug)Ergodryl
How Caffeine, Diphenhydramine, Ergotamine (prescription Drug) interacts with Vitamin K-2 — through 1 ingredient. Tap an ingredient for the detail:
Alfalfa PowderPhotosensitizing Drugs Moderate
Interaction Summary
Theoretically, concomitant use of alfalfa with photosensitizing drugs might have additive effects.
Read the full Alfalfa Powder + Caffeine, Diphenhydramine, Ergotamine (prescription Drug) interactionCanagliflozinInvokana
How Canagliflozin interacts with Vitamin K-2 — through 1 ingredient. Tap an ingredient for the detail:
Alfalfa PowderAntidiabetes Drugs Moderate
Interaction Summary
Theoretically, alfalfa might increase the risk of hypoglycemia when taken with antidiabetes drugs.
Read the full Alfalfa Powder + Canagliflozin interactionCanagliflozin, MetforminInvokamet
How Canagliflozin, Metformin interacts with Vitamin K-2 — through 1 ingredient. Tap an ingredient for the detail:
Alfalfa PowderAntidiabetes Drugs Moderate
Interaction Summary
Theoretically, alfalfa might increase the risk of hypoglycemia when taken with antidiabetes drugs.
Read the full Alfalfa Powder + Canagliflozin, Metformin interactionCanagliflozin, Metformin HydrochlorideInvokamet XR
How Canagliflozin, Metformin Hydrochloride interacts with Vitamin K-2 — through 1 ingredient. Tap an ingredient for the detail:
Alfalfa PowderAntidiabetes Drugs Moderate
Interaction Summary
Theoretically, alfalfa might increase the risk of hypoglycemia when taken with antidiabetes drugs.
Read the full Alfalfa Powder + Canagliflozin, Metformin Hydrochloride interactionCandesartan Cilexetil, HydrochlorothiazideAtacand HCT
How Candesartan Cilexetil, Hydrochlorothiazide interacts with Vitamin K-2 — through 1 ingredient. Tap an ingredient for the detail:
Alfalfa PowderPhotosensitizing Drugs Moderate
Interaction Summary
Theoretically, concomitant use of alfalfa with photosensitizing drugs might have additive effects.
Read the full Alfalfa Powder + Candesartan Cilexetil, Hydrochlorothiazide interactionCapmatinib HydrochlorideTabrecta
How Capmatinib Hydrochloride interacts with Vitamin K-2 — through 1 ingredient. Tap an ingredient for the detail:
Alfalfa PowderPhotosensitizing Drugs Moderate
Interaction Summary
Theoretically, concomitant use of alfalfa with photosensitizing drugs might have additive effects.
Read the full Alfalfa Powder + Capmatinib Hydrochloride interactionCaptoprilAcepril, Capoten
How Captopril interacts with Vitamin K-2 — through 1 ingredient. Tap an ingredient for the detail:
Alfalfa PowderPhotosensitizing Drugs Moderate
Interaction Summary
Theoretically, concomitant use of alfalfa with photosensitizing drugs might have additive effects.
Read the full Alfalfa Powder + Captopril interactionCaptopril, HydrochlorothiazideAcezide, Capozide
How Captopril, Hydrochlorothiazide interacts with Vitamin K-2 — through 1 ingredient. Tap an ingredient for the detail:
Alfalfa PowderPhotosensitizing Drugs Moderate
Interaction Summary
Theoretically, concomitant use of alfalfa with photosensitizing drugs might have additive effects.
Read the full Alfalfa Powder + Captopril, Hydrochlorothiazide interactionCarbamazepineCarbatrol, Carnexiv, Equetro, Tegretol, Tegretol XR
How Carbamazepine interacts with Vitamin K-2 — through 1 ingredient. Tap an ingredient for the detail:
Alfalfa PowderPhotosensitizing Drugs Moderate
Interaction Summary
Theoretically, concomitant use of alfalfa with photosensitizing drugs might have additive effects.
Read the full Alfalfa Powder + Carbamazepine interactionCarbetapentane Tannate, Chlorpheniramine TannateTussi-12
How Carbetapentane Tannate, Chlorpheniramine Tannate interacts with Vitamin K-2 — through 1 ingredient. Tap an ingredient for the detail:
Alfalfa PowderPhotosensitizing Drugs Moderate
Interaction Summary
Theoretically, concomitant use of alfalfa with photosensitizing drugs might have additive effects.
Read the full Alfalfa Powder + Carbetapentane Tannate, Chlorpheniramine Tannate interactionCarbetapentane Tannate, Chlorpheniramine Tannate, Ephedrine Tannate, Phenylephrine TannateQuadratuss, Ry Tuss, Rynatuss, Tri Tannate Plus
How Carbetapentane Tannate, Chlorpheniramine Tannate, Ephedrine Tannate, Phenylephrine Tannate interacts with Vitamin K-2 — through 1 ingredient. Tap an ingredient for the detail:
Alfalfa PowderPhotosensitizing Drugs Moderate
Interaction Summary
Theoretically, concomitant use of alfalfa with photosensitizing drugs might have additive effects.
Read the full Alfalfa Powder + Carbetapentane Tannate, Chlorpheniramine Tannate, Ephedrine Tannate, Phenylephrine Tannate interactionCarbetapentane, Chlorpheniramine, PhenylephrineRicotuss
How Carbetapentane, Chlorpheniramine, Phenylephrine interacts with Vitamin K-2 — through 1 ingredient. Tap an ingredient for the detail:
Alfalfa PowderPhotosensitizing Drugs Moderate
Interaction Summary
Theoretically, concomitant use of alfalfa with photosensitizing drugs might have additive effects.
Read the full Alfalfa Powder + Carbetapentane, Chlorpheniramine, Phenylephrine interactionCarbetapentane, Chlorpheniramine, Phenylephrine, Phenylpropanolamine, Potassium GuaiacolsulfonateCophene-X
How Carbetapentane, Chlorpheniramine, Phenylephrine, Phenylpropanolamine, Potassium Guaiacolsulfonate interacts with Vitamin K-2 — through 1 ingredient. Tap an ingredient for the detail:
Alfalfa PowderPhotosensitizing Drugs Moderate
Interaction Summary
Theoretically, concomitant use of alfalfa with photosensitizing drugs might have additive effects.
Read the full Alfalfa Powder + Carbetapentane, Chlorpheniramine, Phenylephrine, Phenylpropanolamine, Potassium Guaiacolsulfonate interactionCelecoxibCelebrex, Elyxyb
How Celecoxib interacts with Vitamin K-2 — through 1 ingredient. Tap an ingredient for the detail:
Alfalfa PowderPhotosensitizing Drugs Moderate
Interaction Summary
Theoretically, concomitant use of alfalfa with photosensitizing drugs might have additive effects.
Read the full Alfalfa Powder + Celecoxib interactionCelecoxib, TramadolSeglentis
How Celecoxib, Tramadol interacts with Vitamin K-2 — through 1 ingredient. Tap an ingredient for the detail:
Alfalfa PowderPhotosensitizing Drugs Moderate
Interaction Summary
Theoretically, concomitant use of alfalfa with photosensitizing drugs might have additive effects.
Read the full Alfalfa Powder + Celecoxib, Tramadol interactionChlorothiazideDiuril
How Chlorothiazide interacts with Vitamin K-2 — through 1 ingredient. Tap an ingredient for the detail:
Alfalfa PowderPhotosensitizing Drugs Moderate
Interaction Summary
Theoretically, concomitant use of alfalfa with photosensitizing drugs might have additive effects.
Read the full Alfalfa Powder + Chlorothiazide interactionChlorothiazide, MethyldopaAldochlor, Aldoclor 150, Aldoclor 250
How Chlorothiazide, Methyldopa interacts with Vitamin K-2 — through 1 ingredient. Tap an ingredient for the detail:
Alfalfa PowderPhotosensitizing Drugs Moderate
Interaction Summary
Theoretically, concomitant use of alfalfa with photosensitizing drugs might have additive effects.
Read the full Alfalfa Powder + Chlorothiazide, Methyldopa interactionEach ingredient & the kinds of drugs it affects
For each ingredient in Vitamin K-2 with known interactions, here are the types of medications they can affect. Open any type for the detail — or search your exact drug in the checker above.
Alfalfa powder
Warfarin (Coumadin)
Theoretically, alfalfa might reduce the anticoagulant activity of warfarin.
Alfalfa contains a large amount of vitamin K. This could theoretically interfere with the activity of warfarin.
Antidiabetes Drugs
Theoretically, alfalfa might increase the risk of hypoglycemia when taken with antidiabetes drugs.
Animal research suggests that alfalfa decreases blood sugar in diabetic mice. Also, in one case report, a diabetic patient experienced hypoglycemia after consuming alfalfa extract. Monitor blood glucose levels closely. Dose adjustments might be necessary.
Contraceptive Drugs
Theoretically, alfalfa might interfere with the activity of contraceptive drugs.
Alfalfa contains coumestrol, a phytoestrogen, and isoflavonoids, which have estrogenic effects.
Estrogens
Theoretically, alfalfa might interfere with hormone therapy.
Alfalfa contains coumestrol, a phytoestrogen, and isoflavonoids, which have estrogenic effects.
Immunosuppressants
Theoretically, alfalfa might decrease the efficacy of immunosuppressive therapy.
In vitro research and human case reports suggest that alfalfa may have immunostimulant effects.
Photosensitizing Drugs
Theoretically, concomitant use of alfalfa with photosensitizing drugs might have additive effects.
Animal research suggests that excessive doses of alfalfa may increase photosensitivity, possibly due to its chlorophyll content. It is unclear if this effect would be clinically relevant in humans.
Vitamin K2
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.
Brand information
Manufacturer and brand details for Vitamin K-2, from the product label.
U.S. Longevity Institute
See all U.S. Longevity Institute products- Name
- U.S. Longevity Institute
- City
- Mechanicsburg
- State
- PA
- ZipCode
- 17055
- Phone Number
- 1-888-898-6673
- Web Address
- www.uslongevity.com
Vitamin K-2 by U.S. Longevity Institute: Common Questions
Does Vitamin K-2 by U.S. Longevity Institute interact with any medications?
How can one product interact with so many drugs?
Where does this information come from?
Can I take Vitamin K-2 if I'm pregnant?
What are the side effects I might notice?
Can I take this while breastfeeding?
Does Vitamin K-2 actually work for osteoporosis?
Why do I need to be careful with birth control while taking this?
Written and reviewed by the HelloPharmacist editorial staff. Our editorial policy
Not sure if Vitamin K-2 is safe with your meds?
Our pharmacists answer your medication & supplement questions — free.
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.
The Full Monographs Behind Vitamin K-2’s Ingredients
Every ingredient we hold a full HelloPharmacist monograph for — uses, evidence, safety, and the complete interaction list.
Vitamin K
Interacts with 2 drugsVitamin 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 → Herb & supplement monographAlfalfa
Interacts with 583 drugsAlfalfa is a nutrient-rich legume that people use for high cholesterol, menopause symptoms, and general wellness, but solid human evidence for most of these uses is limited. It is best avoid...
Read the full Alfalfa monograph →Sources & How We Checked
Vitamin K-2'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.
- NIH Dietary Supplement Label Database (DSLD) — The official product label on file for this supplement.
- Natural Medicines (Therapeutic Research Center) — Evidence-graded clinical reference behind the ingredient interaction data.
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 43 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
- McEvoy GK, ed. AHFS Drug Information. Bethesda, MD: American Society of Health-System Pharmacists, 1998.
- 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.
- 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
- Dietary vitamin K guidance: an effective strategy for stable control of oral anticoagulation? Nutr Rev. 2010;68(3):178-81. PubMed
- 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
- 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
- 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
- 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
- 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.
- 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
- 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
Alfalfa 32 references
- Newall CA, Anderson LA, Philpson JD. Herbal Medicine: A Guide for Healthcare Professionals. London, UK: The Pharmaceutical Press, 1996.
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