Drug & supplement interaction

Catnip + Levothyroxine, Liothyronine

Levothyroxine, Liothyronine brand name: Armour Thyroid.

No Known Interaction
Medically reviewed by · Updated July 2026 · Pair last verified Sep 13, 2026
The bottom line No known interaction

We found no known interaction between Catnip and Levothyroxine, Liothyronine 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.

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Interaction report

Catnip and Levothyroxine, Liothyronine

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, Liothyronine and Catnip 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.

Catnip safety at a glance

Catnip overall Use caution Likely fine for most adults in tea amounts, but human safety data are limited.
Pregnancy Avoid Avoid during pregnancy, as it may stimulate the uterus and safety is not established.
Breastfeeding Avoid Not enough safety information is available, so it is best avoided.

Safety guidance is general; always confirm with your pharmacist or doctor for your situation.

Still wondering about combining Levothyroxine, Liothyronine and Catnip? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
How we checked

Why No Interaction Is Listed for Levothyroxine, Liothyronine

Interactions in our licensed database are recorded against drug classes, not just single drug names. Levothyroxine, Liothyronine is filed under 3 classifications — including thyroid hormone, oral drugs. Catnip has documented interactions with 2 drug classes — the most serious being cns depressants (moderate) and lithium (moderate) — and none of Levothyroxine, Liothyronine’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.

Keep it in perspective

Catnip Does Interact With Other Medications

Catnip has 248 moderate known drug interactions in our database — Levothyroxine, Liothyronine isn’t one of them. If you take anything else, check it against the full list below.

Moderate 248 No known interaction 2,582 (incl. Levothyroxine, Liothyronine)
Taking anything else?

Check Another of Your Medications Against Catnip

Covers the 2,830 medications we’ve checked against Catnip. Pick one to open its full report.

What to actually watch for

What Catnip Itself Has Been Linked To

This is not an interaction — nothing below involves Levothyroxine, Liothyronine. It is the side-effect record for Catnip on its own, from the licensed Natural Medicines monograph. If something new turns up after you add Catnip, this list is the first place to look.

  • Mood changes or irritability Additional detail

    “Orally, taking too much catnip may result in headache and malaise (6). In one case, a toddler developed a stomachache and irritability, followed by lethargy and a hypnotic state, after ingesting raisins soaked in catnip tea and chewing on the tea bag (5,2596).”

    Catnip · Natural Medicines adverse-effect record, reported in cluster headache.

    3 sources cited
    1. 6. The Review of Natural Products by Facts and Comparisons. St. Louis, MO: Wolters Kluwer Co., 1999.
    2. 5. Foster S, Tyler VE. Tyler's Honest Herbal: A Sensible Guide to the Use of Herbs and Related Remedies. 3rd ed., Binghamton, NY: Haworth Herbal Press, 1993.
    3. 2596. Osterhoudt KC, Lee SK, Callahan JM, Henretig FM. Catnip and the alteration of human consciousness. Vet Hum Toxicol 1997;39:373-5.
  • Tiredness / Headache Additional detail

    “Orally, catnip is generally well-tolerated when used in appropriate amounts.

    Most Common Adverse Effects:

    Orally: Headache, malaise, vomiting.”

    Catnip · Natural Medicines adverse-effect record, reported in cluster headache.

  • Vomiting Additional detail

    “Orally, large amounts of catnip might cause stomachache and vomiting (6,2596).”

    Catnip · Natural Medicines adverse-effect record, reported in nausea and vomiting.

    2 sources cited
    1. 6. The Review of Natural Products by Facts and Comparisons. St. Louis, MO: Wolters Kluwer Co., 1999.
    2. 2596. Osterhoudt KC, Lee SK, Callahan JM, Henretig FM. Catnip and the alteration of human consciousness. Vet Hum Toxicol 1997;39:373-5.

Everything above comes from the Natural Medicines adverse-effect record for Catnip — expand a row for the licensed statement it rests on. We haven’t matched Levothyroxine, Liothyronine to its FDA label in our system yet, so we can’t compare its own side-effect list here — the leaflet that comes with your prescription is the authoritative list for Levothyroxine, Liothyronine.

Everything else you take

See Every Supplement That Interacts With Levothyroxine, Liothyronine

This page covers Catnip only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Levothyroxine, Liothyronine 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, Liothyronine page

“For anyone taking levothyroxine or liothyronine (Armour Thyroid), this list earns real caution, not just a passing glance. Most of these 50 ingredients pull in one of two directions.”

Reviewed by 2 · Jul 18, 2026

Open the Levothyroxine, Liothyronine interaction page

One more smart check

Taking Catnip as Part of a Dietary Supplement Product? Check It for Interactions

We hold 295 real supplement products containing Catnip, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Catnip. Even though Catnip itself has no known interaction with Levothyroxine, Liothyronine, another ingredient on your label might. Find your product and we’ll check every ingredient on its label:

How much people look this up

Where Catnip and Levothyroxine, Liothyronine 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.

Supplement Catnip
Top half

#494 of 1,452 supplements looked up here in the last 7 days

29 days ago today
Medication Levothyroxine, Liothyronine
Top 5%

#61 of 2,830 medications looked up here in the last 7 days

29 days ago today

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 Catnip reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 13, 2026. The Catnip and Levothyroxine, Liothyronine 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.
Data structure & sourcing designed and verified by .
Supplement

About Catnip

What is Catnip?

Catnip
  • Sleep and insomnia
  • Anxiety and stress
  • Digestive upset
  • Cold and flu symptoms
  • Insect repellent

Catnip is a mint-family herb most often used as a calming tea for sleep, anxiety, and minor digestive upset, but solid human research supporting these uses is lacking. It is generally considered fairly safe in small culinary or tea amounts for most adults, but it should be avoided during pregnancy and used cautiously otherwise. Talk to your pharmacist or doctor before using it, especially if you take medications or have a health condition.

Nepeta cataria · Lamiaceae · Leaves, flowers, and essential oil · Tea, capsules, tincture, dried herb, essential oil

An interaction check asks whether these two react with each other — it does not ask whether Catnip is a good idea for someone in your situation. Here is what our Catnip record says about it on its own.

Catnip: dosing

There is no well-established standard dose for catnip. Amounts used in traditional practice vary widely, and reliable dosing guidelines from clinical studies are not available.The safest approach is to follow the directions on the product label and not exceed the recommended amount.

From our Catnip monograph — the full record covers uses, side effects and every documented interaction.

Read the full Catnip monograph & all interactions
Medication

About Levothyroxine, Liothyronine

Most-Reported Side Effects for Levothyroxine, Liothyronine

From FAERS, the FDA’s public side-effect reporting system (15 reports, all brands). Reports are voluntary and are not proof the drug caused the effect.

Fatigue 4 reports
Asthenia 3 reports
Dizziness 3 reports
Arthralgia 2 reports
Disorientation 2 reports
Keep checking

Other Drugs & Catnip

Browse every other medication we’ve checked against Catnip — both the ones with a known interaction and the ones without. Select any drug for the full detail.

0Major
248Moderate
0Minor
2,581No known interaction
248 Moderate 2,581 No interaction
Moderate

248 interactions

Showing 60 of 248 moderate interactions — see all 248 on the Catnip page.

No interaction 2,581 drugs checked — show the list

We also checked Catnip against these medications and found no known interaction in our sources. Open any page to confirm.

Showing the 60 most looked-up of 2,581 medications checked with no known interaction — see the full Catnip list.

See the full Catnip interactions page
See every supplement checked against Levothyroxine, Liothyronine, ranked by severity
Evidence & sources

Catnip References

The 7 references that drive our Catnip 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.

  1. Foster S, Tyler VE. Tyler's Honest Herbal: A Sensible Guide to the Use of Herbs and Related Remedies. 3rd ed., Binghamton, NY: Haworth Herbal Press, 1993.
  2. The Review of Natural Products by Facts and Comparisons. St. Louis, MO: Wolters Kluwer Co., 1999.
  3. Brinker F. Herb Contraindications and Drug Interactions. 2nd ed. Sandy, OR: Eclectic Medical Publications, 1998.
  4. Osterhoudt KC, Lee SK, Callahan JM, Henretig FM. Catnip and the alteration of human consciousness. Vet Hum Toxicol 1997;39:373-5.
  5. Sherry, C. J. and Hunter, P. S. The effect of an ethanol extract of catnip (Nepeta cataria) on the behavior of the young chick. Experientia 2-15-1979;35(2):237-238. PubMed
  6. Harney, J. W., Barofsky, I. M., and Leary, J. D. Behavioral and toxicological studies of cyclopentanoid monoterpenes from Nepeta cataria. Lloydia. 1978;41(4):367-374.
  7. Massoco, C. O., Silva, M. R., Gorniak, S. L., Spinosa, M. S., and Bernardi, M. M. Behavioral effects of acute and long-term administration of catnip (Nepeta cataria) in mice. Vet.Hum.Toxicol 1995;37(6):530-533.

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.

Pharmacist Counseling Corner

Taking Catnip and Levothyroxine, Liothyronine Together: Common Questions

Is it safe to take Catnip with Levothyroxine, Liothyronine?
We do not list a known interaction between Catnip and Levothyroxine, Liothyronine. That does not guarantee the combination is risk-free, so confirm with your pharmacist or doctor — especially if you take other medications or have a health condition.
How was the Catnip and Levothyroxine, Liothyronine combination checked?
Interactions in our licensed database are recorded against drug classes. Levothyroxine, Liothyronine is filed under 3 classifications, and Catnip has documented interactions with 2 drug classes — none of Levothyroxine, Liothyronine's classifications are among them. A medication can belong to classes beyond those recorded in our dataset, so this describes how the check was run rather than guaranteeing safety.
Does Catnip interact with any other medications?
Yes. Catnip has 248 documented drug interactions in our database — Levothyroxine, Liothyronine is simply not one of them. If you take anything else, it is worth checking each one; they are all listed on this page.
Does Levothyroxine, Liothyronine interact with any supplements?
Yes. Levothyroxine, Liothyronine has documented interactions with 50 supplements in our database — Catnip is not one of them. The Levothyroxine, Liothyronine interaction page linked on this page lists every one, ranked by severity.

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

Where next

Keep Exploring

Catnip monograph Uses, safety profile, and every drug interaction in one place Levothyroxine, Liothyronine supplement interactions Every supplement checked against Levothyroxine, Liothyronine, ranked by severity Supplement interaction checker Check any supplement or product against your medications Browse medications A–Z Every drug we’ve checked against herbs & supplements References The 7 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Levothyroxine, Liothyronine and Catnip?

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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.