Tansy + Levothyroxine
Levothyroxine brand names: Euthyrox, Levothroid, Unithroid, Synthroid, Levoxyl, and others.
We found no known interaction between Tansy and Levothyroxine 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 Levothyroxine 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.
Tansy and Levothyroxine
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 Levothyroxine and Tansy 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.
Tansy 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 Levothyroxine
Interactions in our licensed database are recorded against drug classes, not just single drug names. Levothyroxine is filed under 3 classifications — including thyroid hormone, oral drugs. Tansy has documented interactions with 1 drug class — the most serious being alcohol (ethanol) (major) — and none of Levothyroxine’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.
Tansy Does Interact With Other Medications
Tansy has 1 major, known drug interaction in our database — Levothyroxine isn’t one of them. If you take anything else, check it against the full list below.
Check Another of Your Medications Against Tansy
We haven’t checked that one against Tansy yet — ask our pharmacists directly.
Covers the 2,830 medications we’ve checked against Tansy. Pick one to open its full report.
Tansy in Pregnancy & Breastfeeding
When used orally or topically due to potential abortifacient, menstrual flow, and uterine stimulant effects.
When used orally due to thujone content.
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 Levothyroxine Products Have a Food Rule — Tansy Should Not Break It
At least one FDA label for a product containing Levothyroxine says to take it on an empty stomach. Most supplements — Tansy included — are taken with a meal, so the easy mistake is swallowing both together at breakfast. Where that rule applies, keep Levothyroxine on its own and move Tansy 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 Levothyroxine 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.
Questions About Tansy or Levothyroxine
These are real questions from readers, answered by the pharmacists at HelloPharmacist — written by a person, not generated from a database. Each one covers Tansy or Levothyroxine, not necessarily both, but if one is close to what you were about to ask it will usually go further than a database entry can:
- Black Currant Oil With Levothyroxine, Methotrexate, and a Statin ›
- Provitalize With Levothyroxine, Valacyclovir, and Citalopram ›
- Can I Drink Essiac Tea With My Blood Pressure and Thyroid Meds? ›
Not quite your question? Ask our pharmacists directly — it is free, there is no account required, and answers usually come back within 24 hours.
See Every Supplement That Interacts With Levothyroxine
This page covers Tansy only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Levothyroxine page lists 50 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 · 39 moderate · 9 minor.
From our pharmacist’s overview on the Levothyroxine page
“Levothyroxine replaces a hormone your body measures in tiny amounts, so small shifts in its blood level show up in how you feel, and I treat this list with genuine care. Nearly everything on it does one of two things: blocks the pill from being absorbed in the gut, the way everyday minerals like calcium do by binding it into complexes,…”
Reviewed by 2 · Jul 18, 2026
Taking Tansy as Part of a Dietary Supplement Product? Check It for Interactions
We hold 45 real supplement products containing Tansy, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Tansy. Even though Tansy itself has no known interaction with Levothyroxine, another ingredient on your label might. Find your product and we’ll check every ingredient on its label:
Where Tansy and Levothyroxine 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.
#965 of 1,452 supplements looked up here in the last 7 days
#2 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 Tansy reference on this page ↓
- Freshness: we automatically re-check this combination every week — this pair was last verified September 13, 2026. The Tansy and Levothyroxine records this page draws on were last updated July 11, 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 Tansy
What is Tansy?
- Intestinal worms and parasites
- Digestive upset
- Menstrual problems
- Insect repellent
- Skin and wound care (traditional)
Tansy is a traditional bitter herb that contains thujone, a compound that can be toxic in higher amounts. Because of real safety concerns and very limited modern evidence, most people should avoid taking tansy internally, and it should never be used during pregnancy.
Tanacetum vulgare · Asteraceae · Flowers, leaves, and essential oil · Tea, dried herb, tincture, essential oil
An interaction check asks whether these two react with each other — it does not ask whether Tansy is a good idea for someone in your situation. Here is what our Tansy record says about it on its own.
Tansy: dosing
There is no established safe or standardized dose of tansy. Never use the concentrated essential oil internally, and follow all product labels carefully. In most cases, a safer alternative is the better choice.
From our Tansy monograph — the full record covers uses, side effects and every documented interaction.
About Levothyroxine
What Is Levothyroxine Used For?
Brand names: Euthyrox, Levothroid, Unithroid, Synthroid, Levoxyl, Levo-T, Eltroxin, Estre, Levothyroxine, Novothyrox, Levolet
Levothyroxine replaces or supplements the thyroid hormone your body isn't making enough of. It's used for hypothyroidism — an underactive thyroid — in adults, children, and even newborns, whether the cause is the thyroid gland itself, the pituitary gland, or the hypothalamus in the brain.
It's also used alongside surgery and radioiodine treatment in people with certain types of thyroid cancer, to help suppress the hormone that can stimulate cancer growth. It is not meant for weight loss, treating benign thyroid nodules in people who have enough iodine, or for hypothyroidism during recovery from a temporary condition called subacute thyroiditis.
Other Drugs & Tansy
Browse every other medication we’ve checked against Tansy — both the ones with a known interaction and the ones without. Select any drug for the full detail.
No drugs match “”.
1 interaction
No interaction 2,828 drugs checked — show the list
We also checked Tansy against these medications and found no known interaction in our sources. Open any page to confirm.
- Apixaban ›
- Amlodipine ›
- Methylphenidate ›
- Warfarin ›
- Sertraline ›
- Testosterone ›
- Losartan Potassium ›
- Metoprolol ›
- Aspirin ›
- Ivermectin ›
- Rivaroxaban ›
- Rosuvastatin ›
- Escitalopram ›
- Acetaminophen ›
- Tadalafil ›
- Clopidogrel ›
- Atorvastatin ›
- Docusate ›
- Valacyclovir ›
- Hydroxyurea ›
- Abemaciclib ›
- Ibuprofen ›
- Methamphetamine ›
- Sumatriptan ›
- Semaglutide ›
- Tirzepatide ›
- Warfarin Sodium ›
- Prednisone ›
- Propranolol ›
- Bupropion ›
- Lisdexamfetamine ›
- Metformin ›
- Amoxicillin ›
- Acyclovir ›
- Lisinopril ›
- Bendamustine ›
- Amitriptyline ›
- Doxycycline ›
- Methotrexate ›
- Fluoxetine ›
- Lamotrigine ›
- Amphetamine ›
- Gabapentin ›
- Pregabalin ›
- Acetaminophen, Codeine ›
- Azithromycin ›
- Dextroamphetamine ›
- Isotretinoin ›
- Clonazepam ›
- Omeprazole ›
- Quetiapine ›
- Methylene Blue ›
- Amlodipine Besylate ›
- Duloxetine ›
- Letrozole ›
- Buspirone ›
- Citalopram ›
- Naproxen ›
- Ciprofloxacin ›
- Bisoprolol ›
Showing the 60 most looked-up of 2,828 medications checked with no known interaction — see the full Tansy list.
Tansy References
The 14 references that drive our Tansy 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.
- Blumenthal M, ed. The Complete German Commission E Monographs: Therapeutic Guide to Herbal Medicines. Trans. S. Klein. Boston, MA: American Botanical Council, 1998.
- Newall CA, Anderson LA, Philpson JD. Herbal Medicine: A Guide for Healthcare Professionals. London, UK: The Pharmaceutical Press, 1996.
- The Review of Natural Products by Facts and Comparisons. St. Louis, MO: Wolters Kluwer Co., 1999.
- Schulz V, Hansel R, Tyler VE. Rational Phytotherapy: A Physician's Guide to Herbal Medicine. Terry C. Telger, transl. 3rd ed. Berlin, GER: Springer, 1998.
- McGuffin M, Hobbs C, Upton R, Goldberg A, eds. American Herbal Products Association's Botanical Safety Handbook. Boca Raton, FL: CRC Press, LLC 1997.
- Gruenwald J, Brendler T, Jaenicke C. PDR for Herbal Medicines. 1st ed. Montvale, NJ: Medical Economics Company, Inc., 1998.
- Brinker F. Herb Contraindications and Drug Interactions. 2nd ed. Sandy, OR: Eclectic Medical Publications, 1998.
- Jovanovic, M. and Poljacki, M. [Compositae dermatitis]. Med Pregl. 2003;56(1-2):43-49. PubMed
- Guin, J. D. and Skidmore, G. Compositae dermatitis in childhood. Arch Dermatol. 1987;123(4):500-502. DOI
- Jovanovic, M., Poljacki, M., Duran, V., Vujanovic, L., Sente, R., and Stojanovic, S. Contact allergy to Compositae plants in patients with atopic dermatitis. Med Pregl. 2004;57(5-6):209-218. PubMed
- Mark, K. A., Brancaccio, R. R., Soter, N. A., and Cohen, D. E. Allergic contact and photoallergic contact dermatitis to plant and pesticide allergens. Arch Dermatol. 1999;135(1):67-70. PubMed
- McGuffin M and et al. American Herbal Products Association's Botanical Safety Handbook. 1997.
- The Review of Natural Products by Facts and Comparisons. 1999.
- Blumenthal, M and et al. The Complete German Commission E Monographs: Therapeutic Guide to Herbal Medicines. 1998;
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 Tansy and Levothyroxine Together: Common Questions
Is it safe to take Tansy with Levothyroxine?
Do Tansy and Levothyroxine have any of the same side effects?
Should I take Tansy and Levothyroxine at the same time of day?
How was the Tansy and Levothyroxine combination checked?
Does Tansy interact with any other medications?
Does Levothyroxine 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.