Vitamin K + Liotrix
Liotrix brand names: Euthroid 3, Euthroid 1/2, Euthroid 1.
We found no known interaction between Vitamin K and Liotrix in our sources. Absence of a documented interaction is not the same as proven safety, and does not guarantee one does not exist. Do not start, stop, or change a medication or supplement based on this page; confirm with your pharmacist or doctor first. Additionally, although there is no interaction, the label for Liotrix states a food rule worth keeping to, and the two are separately associated with some of the same side effects, which would make a new symptom harder to attribute to one or the other.
Vitamin K and Liotrix
We checked these two against our interaction database. Here is what we found.
No Known Interaction Found
We did not find a documented interaction between Liotrix and Vitamin K in our sources. This does not guarantee that the combination is completely free of risk — there is often limited research on supplements and herbal products, especially around drug interactions.
If you decide to take both, the practical routine is simple: add one new thing at a time and note the date you started it. If the combination is going to disagree with you, it usually shows in the first days to a couple of weeks — and a start date turns “I’ve been feeling off” into something a pharmacist can actually work with. Do not stop a prescribed medicine on your own.
Always talk with your pharmacist or doctor before making changes to your medications or supplements, particularly if you take several medications or have an ongoing health condition.
Vitamin K safety at a glance
Pregnancy & breastfeeding ratings are from Natural Medicines (Therapeutic Research Center) — the full detail is in the Special populations card below. Safety guidance is general; always confirm with your pharmacist or doctor for your situation.
Why No Interaction Is Listed for Liotrix
Interactions in our licensed database are recorded against drug classes, not just single drug names. Liotrix is filed under 2 classifications — thyroid hormone, oral drugs. Vitamin K has documented interactions with 1 drug class — the most serious being warfarin (coumadin) (major) — and none of Liotrix’s classifications are among them.
Classification data comes from our licensed Natural Medicines dataset. A medication can belong to classes beyond those recorded there, so this describes how the check was run — it is not a safety guarantee.
Vitamin K Does Interact With Other Medications
Vitamin K has 2 major, known drug interactions in our database — Liotrix isn’t one of them. If you take anything else, check it against the full list below.
Check Another of Your Medications Against Vitamin K
We haven’t checked that one against Vitamin K yet — ask our pharmacists directly.
Covers the 2,830 medications we’ve checked against Vitamin K. Pick one to open its full report.
Vitamin K in Pregnancy & Breastfeeding
When used orally in amounts that do not exceed the daily adequate intake level (AI). A tolerable upper intake level for vitamin K in pregnancy and lactation has not been set.
DISCLAIMER: This tool is intended for informational purposes only, and should not be interpreted as specific medical advice. Patients should consult with a qualified healthcare provider before making decisions about therapies and/or health conditions.© 2026 Therapeutic Research Center
Some Liotrix Products Have a Food Rule — Vitamin K Should Not Break It
At least one FDA label for a product containing Liotrix says to take it on an empty stomach. Most supplements — Vitamin K included — are taken with a meal, so the easy mistake is swallowing both together at breakfast. Where that rule applies, keep Liotrix on its own and move Vitamin K to a meal later in the day.
This may not be true of your version. Food instructions belong to the product, not the ingredient: two Liotrix products can carry different directions, and extended-release forms often differ from immediate-release ones. The label we read is quoted below — check the directions on your own box or bottle, or ask your pharmacist, for how to take the exact product you were given.
A food rule is not an interaction — it is about how much of the medicine you absorb. The directions that came with your own product, and your pharmacist, outrank anything on this page.
What Liotrix Is Prescribed For, and What Vitamin K Has Been Studied For
These two come up together because they touch the same health topic — not because they do the same job. Liotrix is a prescription medicine with approved uses on its FDA label. Vitamin K is a supplement: what follows is what researchers have looked at it for, and how strong that evidence is.
Vitamin K has been studied for:
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Depression studied, not established Vitamin K has been studied for this. Natural Medicines rates the evidence: Insufficient Reliable Evidence To Rate Read what the research shows
Vitamin K for depression
It is unclear if dietary intake of vitamin K reduces depression.
Effectiveness ratings and the research summaries above are the verbatim record from the Natural Medicines database, which grades evidence from “Effective” down to “Insufficient Reliable Evidence To Rate”. A rating below the top of that scale means researchers have looked at it — not that it works, and never that it can stand in for a prescribed medicine. Do not stop or replace Liotrix on your own; if you are taking Vitamin K for the same health topic, tell your prescriber, especially if the medicine is being adjusted to a target.
See Every Supplement That Interacts With Liotrix
This page covers Vitamin K only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Liotrix page lists 38 supplements it has a documented interaction with, worst first, each one explained.
The most serious there right now: Activated Charcoal (major), Tiratricol (major), Acetyl-l-carnitine (moderate), Alpha-lipoic Acid (moderate) and Ascophyllum Nodosum (moderate).
By severity: 2 major · 26 moderate · 10 minor.
From our pharmacist’s overview on the Liotrix page
“Liotrix (Euthroid) combines both thyroid hormones, and since steady hormone levels are the entire point of treatment, this list deserves a slow, serious read. Most entries fall into two camps: twenty-one ingredients act on the hormone itself, some boosting it and others blunting it, while another seventeen change how well the dose is a…”
Reviewed by 2 · Jul 18, 2026
Taking Vitamin K as Part of a Dietary Supplement Product? Check It for Interactions
We hold 5,292 real supplement products containing Vitamin K, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Vitamin K. Even though Vitamin K itself has no known interaction with Liotrix, another ingredient on your label might. Find your product and we’ll check every ingredient on its label:
Where Vitamin K and Liotrix Sit Against Everything Else
Out of every supplement and medication people look up on HelloPharmacist, here is where these two land this week — and which way each has been moving.
#27 of 1,452 supplements looked up here in the last 7 days
#1,321 of 2,830 medications looked up here in the last 7 days
Position among everything looked up on this site, not a measure of how commonly either one is used or how important it is. A supplement can climb this list because of a news story. It counts every request to the page, automated ones included, and nothing here identifies anyone.
Where does our data come from?
- Source: the Natural Medicines (TRC Healthcare) clinical database — the evidence-graded professional reference for herb & supplement interactions.
- Citation library: 103,510 references behind our interaction content, 65,311 of them resolved to verified PubMed/DOI sources. See every Vitamin K reference on this page ↓
- Freshness: we automatically re-check this combination every week — this pair was last verified September 20, 2026. The Vitamin K and Liotrix records this page draws on were last updated July 10, 2026.
- What “no known interaction” means: no documented interaction in the sources above — not a guarantee of safety. Supplements are studied far less than prescription drugs, so we say exactly what the evidence supports, and nothing more.
About Vitamin K
What is Vitamin K?
- Supporting normal blood clotting
- Bone health
- Heart and vascular health
- Correcting vitamin K deficiency
- Newborn bleeding prevention (medical injection)
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 or bone and heart health, where evidence is mixed. If you take a blood thinner, talk to your pharmacist or doctor before changing your vitamin K intake.
Fat-soluble vitamin (K1 from plants, K2 from animal sources and bacteria) · Capsules, softgels, tablets, drops, injections (medical use)
An interaction check asks whether these two react with each other — it does not ask whether Vitamin K is a good idea for someone in your situation. Here is what our Vitamin K record says about it on its own.
Vitamin K: dosing
There is no single "best" supplement dose for everyone, and needs vary by age, sex, and health status. Nutrition authorities have set general daily intake recommendations for vitamin K that most people can meet through diet.If you choose to take a supplement, follow the directions on the product label and do not take more than recommended without medical advice.
From our Vitamin K monograph — the full record covers uses, side effects and every documented interaction.
About Liotrix
What Is Liotrix Used For?
Brand names: Euthroid 3, Euthroid 1/2, Euthroid 1
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Liotrix is used to treat hypothyroidism (a condition that results when the thyroid gland does not produce enough thyroid hormone). Symptoms of hypothyroidism include lack of energy, depression, constipation, weight gain, hair loss, dry skin, dry coarse hair, muscle cramps, decreased concentration, aches and pains, swelling of the legs, and increased sensitivity to cold. When taken correctly, liotrix can reverse these symptoms. Liotrix is also used to treat goiter (enlarged thyroid gland). This medication is also used to test for hyperthyroidism (a condition where the thyroid gland produces too much thyroid hormone). Liotrix is in a class of medications called thyroid agents. It works by supplying the thyroid hormones normally produced by the body.
Other Drugs & Vitamin K
Browse every other medication we’ve checked against Vitamin K — both the ones with a known interaction and the ones without. Select any drug for the full detail.
No drugs match “”.
2 interactions
No interaction 2,827 drugs checked — show the list
We also checked Vitamin K against these medications and found no known interaction in our sources. Open any page to confirm.
- Apixaban ›
- Levothyroxine ›
- Amlodipine ›
- Methylphenidate ›
- Sertraline ›
- Abemaciclib ›
- Ivermectin ›
- Testosterone ›
- Acetaminophen ›
- Losartan Potassium ›
- Aspirin ›
- Rosuvastatin ›
- Metoprolol ›
- Clopidogrel ›
- Escitalopram ›
- Rivaroxaban ›
- Atorvastatin ›
- Docusate ›
- Tirzepatide ›
- Ibuprofen ›
- Methamphetamine ›
- Tadalafil ›
- Valacyclovir ›
- Hydroxyurea ›
- Sumatriptan ›
- Semaglutide ›
- Prednisone ›
- Amitriptyline ›
- Propranolol ›
- Metformin ›
- Lisdexamfetamine ›
- Isotretinoin ›
- Amoxicillin ›
- Methotrexate ›
- Lisinopril ›
- Amlodipine Besylate ›
- Amphetamine ›
- Bendamustine ›
- Bupropion ›
- Fluoxetine ›
- Doxycycline ›
- Azithromycin ›
- Pregabalin ›
- Acyclovir ›
- Lamotrigine ›
- Dextroamphetamine ›
- Gabapentin ›
- Levothyroxine, Liothyronine ›
- Acetaminophen, Codeine ›
- Naproxen ›
- Clonazepam ›
- Quetiapine ›
- Omeprazole ›
- Duloxetine ›
- Letrozole ›
- Methylene Blue ›
- Citalopram ›
- Buspirone ›
- Ciprofloxacin ›
- Bisoprolol ›
Showing the 60 most looked-up of 2,827 medications checked with no known interaction — see the full Vitamin K list.
Vitamin K References
The 11 references that drive our Vitamin K monograph and interaction data, from the evidence-graded Natural Medicines (TRC Healthcare) database. Citations with a link open the study on PubMed or the publisher’s site.
- 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
Medication overviews come from MedlinePlus (NIH); supplement label data from the NIH Dietary Supplement Label Database. Content is written and reviewed by licensed HelloPharmacist pharmacists — see our data sources and editorial standards.
Taking Vitamin K and Liotrix Together: Common Questions
Is it safe to take Vitamin K with Liotrix?
Do Vitamin K and Liotrix have any of the same side effects?
Should I take Vitamin K and Liotrix at the same time of day?
Are Vitamin K and Liotrix used for the same thing?
How was the Vitamin K and Liotrix combination checked?
Does Vitamin K interact with any other medications?
Does Liotrix interact with any supplements?
Written and reviewed by the HelloPharmacist editorial staff. Our editorial policy
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This information is for education only and is not a substitute for professional medical advice. Always check with your pharmacist or doctor before starting, stopping, or combining supplements and medications.