Drug & supplement interaction

Licorice + Levothyroxine, Liothyronine

Levothyroxine, Liothyronine brand name: Armour Thyroid.

No Known Interaction

Medically reviewed by Dr. Brian Staiger, PharmD, BCPS · Updated July 2026 · Pair last verified Sep 13, 2026

The bottom line No known interaction

We found no known interaction between Licorice 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.

Know someone taking this? Share

Facebook Post Reddit Email

On this page

Interaction report

Licorice 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 Licorice 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.

Licorice safety at a glance

Licorice overall Use caution Generally fine in small food amounts, but glycyrrhizin can cause serious problems with high doses or long-term use.

Pregnancy Unsafe When used orally. Licorice has abortifacient, estrogenic, and steroid effects. It can also cause uterine stimulation. Heavy consumption of licorice, equivalent... Read the full pregnancy detail

Breastfeeding Avoid Not enough reliable safety information, so it is best avoided while breastfeeding.

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.

Still wondering about combining Levothyroxine, Liothyronine and Licorice? 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. Licorice has documented interactions with 18 drug classes — the most serious being antihypertensive drugs (moderate), cisplatin (platinol-aq) (moderate) and corticosteroids (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

Licorice Does Interact With Other Medications

Licorice has 977 moderate, 63 minor 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 977 Minor 63 No known interaction 1,790 (incl. Levothyroxine, Liothyronine)

Taking anything else?

Check Another of Your Medications Against Licorice

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

What to actually watch for

What Licorice Itself Has Been Linked To

This is not an interaction — nothing below involves Levothyroxine, Liothyronine. It is the side-effect record for Licorice on its own, from the licensed Natural Medicines monograph. If something new turns up after you add Licorice, this list is the first place to look. 4 entries are worth acting on rather than waiting out — marked below.

Severe muscle breakdown Worth acting on Additional detail
“Orally, excessive licorice ingestion can cause a syndrome of apparent mineralocorticoid excess, or pseudohyperaldosteronism, with sodium and water retention, increased urinary potassium loss, hypokalemia, and metabolic alkalosis due to its glycyrrhizin content.”

Licorice · Natural Medicines adverse-effect record, reported in arrhythmia.
6 sources cited

781. Farese RV Jr, Biglieri EG, Shackleton CH, et al. Licorice-induced hypermineralocorticoidism. N Engl J Med 1991;325:1223-7. PubMed

10619. Hussain RM. The sweet cake that reaches parts other cakes can't! Postgrad Med J 2003;79:115-6.. PubMed

15591. de Klerk GJ, Nieuwenhuis G, Beutler JJ. Hypokalaemia and hypertension associated with use of liquorice flavoured chewing gum. BMJ 1997;314:731-2.

15592. Dellow EL, Unwin RJ, Honour JW. Pontefract cakes can be bad for you: refractory hypertension and liquorice excess. Nephol Dial Transplant 1999;14:218-20. PubMed

15593. Elinav E, Chajek-Shaul T. Licorice consumption causing severe hypokalemic paralysis. Mayo Clin Proc 2003;78:767-8. PubMed

15594. Eriksson JW, Carlberg B, Hillom V. Life-threatening ventricular tachycardia due to liquorice-induced hypokalemia. J Intern Med 1999;245:307-10.
Muscle weakness Worth acting on Additional detail

“Orally, licorice is generally well tolerated when used in amounts commonly found in foods. It seems to be well tolerated when licorice products that do not contain glycyrrhizin (deglycyrrhizinated licorice) are used orally and appropriately for medicinal purposes or when used topically, short-term.

Most Common Adverse Effects:

Orally: Headache, nausea, and vomiting.

Topically: Contact dermatitis.

Intravenously: Diarr…”

Licorice · Natural Medicines adverse-effect record, reported in arrhythmia.
Low potassium / An irregular heartbeat / Seizures / Kidney problems / Raised blood pressure Worth acting on Additional detail
“Orally, excessive licorice ingestion can lead to pseudohyperaldosteronism, which can precipitate cardiovascular complications such as hypertension and hypertensive crisis, ventricular fibrillation or tachycardia, sinus pause, and cardiac arrest. These effects are due to the licorice constituent glycyrrhizin and usually occur when 20-30 grams or more of licorice product is consumed daily for several weeks.”

Licorice · Natural Medicines adverse-effect record, reported in arrhythmia.
6 sources cited

781. Farese RV Jr, Biglieri EG, Shackleton CH, et al. Licorice-induced hypermineralocorticoidism. N Engl J Med 1991;325:1223-7. PubMed

15590. Brayley J, Jones J. Life-threatening hypokalemia associated with excessive licorice ingestion (letter). Am J Psychiatry 1994;151:617-8. PubMed

15592. Dellow EL, Unwin RJ, Honour JW. Pontefract cakes can be bad for you: refractory hypertension and liquorice excess. Nephol Dial Transplant 1999;14:218-20. PubMed

15594. Eriksson JW, Carlberg B, Hillom V. Life-threatening ventricular tachycardia due to liquorice-induced hypokalemia. J Intern Med 1999;245:307-10.

15596. Lin SH, Yang SS, Chau T, Halperin ML. An unusual cause of hypokalemic paralysis: chronic licorice ingestion. Am J Med Sci 2003;325:153-6. PubMed

15597. van den Bosch AE, van der Klooster JM, Zuidgeest DM, et al. Severe hypokalemic paralysis and rhabdomyolysis due to ingestion of liquorice. Neth J Med 2005;63:146-8.
Fainting Worth acting on Additional detail

Recorded for Licorice in the same Natural Medicines adverse-effect record shown under Low potassium / An irregular heartbeat / Seizures / Kidney problems / Raised blood pressure above.
Acne Additional detail
“There have been reports of contact allergy, resulting in an itchy reddish eruption, occurring in patients that applied cosmetic products containing oil-soluble licorice extracts. There have also been at least 3 cases of allergic contact dermatitis reported with the topical application of glycyrrhizin-containing products to damaged skin.”

Licorice · Natural Medicines adverse-effect record, reported in acne.
2 sources cited

59912. Nishioka, K. and Seguchi, T. Contact allergy due to oil-soluble licorice extracts in cosmetic products. Contact Dermatitis 1999;40(1):56. PubMed

108578. Gatica-Ortega ME, Pastor-Nieto MA. Allergic contact dermatitis to Glycyrrhiza inflata root extract in an anti-acne cosmetic product. Contact Dermatitis 2021;85(4):454-455.
A fast or pounding heartbeat Additional detail

Recorded for Licorice in the same Natural Medicines adverse-effect record shown under Low potassium / An irregular heartbeat / Seizures / Kidney problems / Raised blood pressure above.

Showing the 10 most notable of 18 recorded effects — ranked by how unusual each one is across medicines generally, with serious effects weighted up.

Everything above comes from the Natural Medicines adverse-effect record for Licorice — 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.

Special populations

Licorice in Pregnancy & Breastfeeding

Pregnancy Unsafe

When used orally. Licorice has abortifacient, estrogenic, and steroid effects. It can also cause uterine stimulation. Heavy consumption of licorice, equivalent to 500 mg of glycyrrhizin per week (about 250 grams of licorice per week), during pregnancy seems to increase the risk of delivery before gestational age of 38 weeks. Furthermore, high intake of glycyrrhizin, at least 500 mg per week, during pregnancy is associated with increased salivary cortisol levels in the child by the age of 8 years. This suggests that high intake of licorice during pregnancy may increase hypothalamic-pituitary-adrenocortical axis activity in the child; avoid using.

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

From our Q&A

Questions About Licorice or Levothyroxine, Liothyronine

These are real questions from readers, answered by the pharmacists at HelloPharmacist — written by a person, not generated from a database. Each one covers Licorice or Levothyroxine, Liothyronine, 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:

Not quite your question? Ask our pharmacists directly — it is free, there is no account required, and answers usually come back within 24 hours.

Everything else you take

See Every Supplement That Interacts With Levothyroxine, Liothyronine

This page covers Licorice 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 Licorice as Part of a Dietary Supplement Product? Check It for Interactions

We hold 4,721 real supplement products containing Licorice, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Licorice. Even though Licorice 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 Licorice 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 Licorice

Top 5%

#37 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 Licorice reference on this page ↓
Freshness: we automatically re-check this combination every week — this pair was last verified September 13, 2026. The Licorice and Levothyroxine, Liothyronine 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.

Data structure & sourcing designed and verified by Dr. Brian Staiger, PharmD, BCPS.

Supplement

About Licorice

What is Licorice?

Sore throat and cough
Heartburn and stomach upset
Mouth ulcers and digestive complaints
Inflammation
Traditional tonic/adrenal support

Licorice root is a traditional remedy used for sore throats, coughs, and digestive complaints, but solid human evidence is limited for most uses. Regular licorice contains glycyrrhizin, which can raise blood pressure and lower potassium when taken in large amounts or for a long time, so deglycyrrhizinated (DGL) products are often preferred. Talk to your pharmacist or doctor before using it, especially if you have high blood pressure, heart, or kidney problems.

Glycyrrhiza glabra · Fabaceae · Root · Tea, capsules, tablets (including DGL chewable tablets), liquid extract, lozenges, dried root, candy

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

Licorice: dosing

There is no single well-established standard dose of licorice for any condition, and the safe amount depends on whether the product contains glycyrrhizin. Health authorities generally warn against consuming large amounts of glycyrrhizin, especially daily over weeks or longer.The safest approach is to follow the directions on the product label and not exceed the recommended amount. DGL products are often preferred for ongoing use.

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

Read the full Licorice 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 & Licorice

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

0Major

977Moderate

63Minor

1,789No known interaction

977 Moderate 63 Minor 1,789 No interaction

Moderate

977 interactions

Showing 60 of 977 moderate interactions — see all 977 on the Licorice page.

Minor

63 interactions

Showing 60 of 63 minor interactions — see all 63 on the Licorice page.

No interaction 1,789 drugs checked — show the list

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

Showing the 60 most looked-up of 1,789 medications checked with no known interaction — see the full Licorice list.

See the full Licorice interactions page

See every supplement checked against Levothyroxine, Liothyronine, ranked by severity

Evidence & sources

Licorice References

The 92 references that drive our Licorice 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.

Farese RV Jr, Biglieri EG, Shackleton CH, et al. Licorice-induced hypermineralocorticoidism. N Engl J Med 1991;325:1223-7. PubMed
Sigurjonsdottir HA, Ragnarsson J, Franzson L, Sigurdsson G. Is blood pressure commonly raised by moderate consumption of liquorice? J Hum Hypertens 1995;9:345-8.
Armanini D, Lewicka S, Pratesi C, et al. Further studies on the mechanism of the mineralocorticoid action of licorice in humans. J Endocrinol Invest 1996;19:624-9. PubMed
Zhang YD, Lorenzo B, Reidenberg MM. Inhibition of 11 beta hydroxysteroid dehydrogenase obtained from guinea pig kidney by furosemide, naringenin and some other compounds. J Steroid Biochem Mol Biol 1994;49:81-5.
Strandberg TE, Jarvenpaa AL, Vanhanen H, McKeigue PM. Birth outcome in relation to licorice consumption during pregnancy. Am J Epidemiol 2001;153:1085-8. PubMed
Sigurjonsdottir HA, Franzson L, Manhem K, et al. Liquorice-induced rise in blood pressure: a linear dose-response relationship. J Hum Hypertens 2001;15:549-52. PubMed
Amato P, Christophe S, Mellon PL. Estrogenic activity of herbs commonly used as remedies for menopausal symptoms. Menopause 2002;9:145-50. PubMed
Kent UM, Aviram M, Rosenblat M, Hollenberg PF. The licorice root derived isoflavan glabridin inhibits the activities of human cytochrome P450S 3A4, 2B6, and 2C9. Drug Metab Dispos 2002;30:709-15.. PubMed
Yoshida S, Takayama Y. Licorice-induced hypokalemia as a treatable cause of dropped head syndrome. Clin Neurol Neurosurg 2003;105:286-7.. PubMed
Strandberg TE, Andersson S, Jarvenpaa AL, et al. Preterm birth and licorice consumption during pregnancy. Am J Epidemiol 2002;156:803-5.. PubMed
Hussain RM. The sweet cake that reaches parts other cakes can't! Postgrad Med J 2003;79:115-6.. PubMed
Morris DJ, Davis E, Latif SA. Licorice, tobacco chewing, and hypertension. N Engl J Med 1990;322:849-50. PubMed
Quinkler M, Stewart PM. Hypertension and the cortisol-cortisone shuttle. J Clin Endocrinol Metab 2003;88:2384-92. PubMed
Westman EC, Guthrie GP. Licorice, tobacco chewing, and hypertension. N Engl J Med 1990;322:850. PubMed
Mu Y, Zhang J, Zhang S, et al. Traditional Chinese medicines Wu Wei Zi (Schisandra chinensis Baill) and Gan Cao (Glycyrrhiza uralensis Fisch) activate pregnane X receptor and increase warfarin clearance in rats. J Pharmacol Exp Ther 2006;316:1369-77. PubMed
Yasue H, Itoh T, Mizuno Y, Harada E. Severe hypokalemia, rhabdomyolysis, muscle paralysis, and respiratory impairment in a hypertensive patient taking herbal medicines containing licorice. Intern Med 2007;46:575-8. PubMed
Brayley J, Jones J. Life-threatening hypokalemia associated with excessive licorice ingestion (letter). Am J Psychiatry 1994;151:617-8. PubMed
de Klerk GJ, Nieuwenhuis G, Beutler JJ. Hypokalaemia and hypertension associated with use of liquorice flavoured chewing gum. BMJ 1997;314:731-2.
Dellow EL, Unwin RJ, Honour JW. Pontefract cakes can be bad for you: refractory hypertension and liquorice excess. Nephol Dial Transplant 1999;14:218-20. PubMed
Elinav E, Chajek-Shaul T. Licorice consumption causing severe hypokalemic paralysis. Mayo Clin Proc 2003;78:767-8. PubMed
Eriksson JW, Carlberg B, Hillom V. Life-threatening ventricular tachycardia due to liquorice-induced hypokalemia. J Intern Med 1999;245:307-10.
Janse A, van Iersel M, Hoefnagels WH, Olde Rikker MG. The old lady who liked liquorice: hypertension due to chronic intoxication in a memory-impaired patient. Neth J Med 2005;63:149-50.
Lin SH, Yang SS, Chau T, Halperin ML. An unusual cause of hypokalemic paralysis: chronic licorice ingestion. Am J Med Sci 2003;325:153-6. PubMed
van den Bosch AE, van der Klooster JM, Zuidgeest DM, et al. Severe hypokalemic paralysis and rhabdomyolysis due to ingestion of liquorice. Neth J Med 2005;63:146-8.
van Uum SH. Liquorice and hypertension. Neth J Med 2005;63:119-20.
Russo S, Mastropasqua M, Mosetti MA, et al. Low doses of liquorice can induce hypertension encephalopathy. Am J Nephrol 2000;20:145-8. PubMed
Stormer FC, Reistad R, Alexander J. Glycyrrhizic acid in liquorice - evaluation of health hazard. Food Chem Toxicol 1993;31:303-12. PubMed
Sontia B, Mooney J, Gaudet L, Touyz RM. Pseudohyperaldosteronism, liquorice, and hypertension. J Clin Hypertens (Greenwich) 2008;10:153-7. PubMed
Francini-Pesenti F, Puato M, Piccoli A, Brocadello F. Liquorice-induced hypokalaemia and water retention in the absence of hypertension. Phytother Res 2008;22:563-5. PubMed
Lapi F, Gallo E, Bernasconi S, et al. Myopathies associated with red yeast rice and liquorice: spontaneous reports from the Italian Surveillance System of Natural Health Products. Br J Clin Pharmacol 2008;66:572-4. PubMed
Chen MF, Shimada F, Kato H, Yano S, Kanaoka M. Effect of glycyrrhizin on the pharmacokinetics of prednisolone following low dosage of prednisolone hemisuccinate. Endocrinol Jpn 1990;37:331-41. PubMed
Teelucksingh S, Mackie AD, Burt D, McIntyre MA, Brett L, Edwards CR. Potentiation of hydrocortisone activity in skin by glycyrrhetinic acid. Lancet 1990;335(8697):1060-3. PubMed
Heidemann HT, Kreuzfelder E. Hypokalemic rhabdomyolysis with myoglobinuria due to licorice ingestion and diuretic treatment. Klin Wochenschr 1983;61:303-5. PubMed
Hukkanen J, Ukkola O, Savolainen MJ. Effects of low-dose liquorice alone or in combination with hydrochlorothiazide on the plasma potassium in healthy volunteers. Blood Press 2009;18:192-5. PubMed
Bisogni V, Rossi GP, Calò LA. Apparent mineralcorticoid excess syndrome, an often forgotten or unrecognized cause of hypokalemia and hypertension: case report and appraisal of the pathophysiology. Blood Press. 2014 Jun;23(3):189-92. PubMed
Dehours E, Vallé B, Rougé-Bugat ME, Florent B, Bounes V, Franchitto N. Suspected hypokalaemia following liquorice ingestion on board ship. J Telemed Telecare. 2013 Jun;19(4):227-8. PubMed
Kormann R, Languille E, Amiot HM, Hertig A. Dying for a cup of tea. BMJ Case Rep. 2012 Oct 19;2012. PubMed
Panduranga P, Al-Rawahi N. Licorice-induced severe hypokalemia with recurrent torsade de pointes. Ann Noninvasive Electrocardiol. 2013 Nov;18(6):593-6. PubMed
Räikkönen K, Seckl JR, Heinonen K, Pyhälä R, Feldt K, Jones A, Pesonen AK, Phillips DI, Lahti J, Järvenpää AL, Eriksson JG, Matthews KA, Strandberg TE, Kajantie E. Maternal prenatal licorice consumption alters hypothalamic-pituitary-adrenocortical axis fu
Robles BJ, Sandoval AR, Dardon JD, Blas CA. Lethal liquorice lollies (liquorice abuse causing pseudohyperaldosteronism). BMJ Case Rep. 2013 Sep 19;2013. PubMed
Chamberlain, J. J. and Abolnik, I. Z. Pulmonary edema following a licorice binge. West J Med 1997;167(3):184-185.
Barrella, M., Lauria, G., Quatrale, R., and Paolino, E. Hypokaliemic rhabdomyolysis associated with liquorice ingestion: report of an atypical case. Ital.J Neurol.Sci 1997;18(4):217-220. PubMed
Fugh-Berman, A. Herb-drug interactions. Lancet 2000;355(9198):134-138. PubMed
Hasegawa, J., Suyama, Y., Kinugawa, T., Morisawa, T., and Kishimoto, Y. Echocardiographic findings of the heart resembling dilated cardiomyopathy during hypokalemic myopathy due to licorice-induced pseudoaldosteronism. Cardiovasc.Drugs Ther 1998;12(6):59 PubMed
van Rossum, T. G., Vulto, A. G., Hop, W. C., Brouwer, J. T., Niesters, H. G., and Schalm, S. W. Intravenous glycyrrhizin for the treatment of chronic hepatitis C: a double-blind, randomized, placebo-controlled phase I/II trial. J Gastroenterol Hepatol 199 PubMed
Lozano, P., Flores, D., Martinez, S., Artigues, I., Rimbau, E. M., and Gomez, F. Upper limb ischemia induced by chronic licorice ingestion. J Cardiovasc.Surg (Torino) 2000;41(4):631-632.
Brouwers, A. J. and van der, Meulen J. ['Licorice hypertension' also caused by licorice tea]. Ned.Tijdschr Geneeskd. 4-14-2001;145(15):744-747.
van Rossum, T. G., Vulto, A. G., Hop, W. C., and Schalm, S. W. Glycyrrhizin-induced reduction of ALT in European patients with chronic hepatitis C. Am J Gastroenterol 2001;96(8):2432-2437. PubMed
Sigurjonsdottir, H. A., Manhem, K., Axelson, M., and Wallerstedt, S. Subjects with essential hypertension are more sensitive to the inhibition of 11 beta-HSD by liquorice. J Hum Hypertens 2003;17(2):125-131.
Shintani, S., Murase, H., Tsukagoshi, H., and Shiigai, T. Glycyrrhizin (licorice)-induced hypokalemic myopathy. Report of 2 cases and review of the literature. Eur Neurol 1992;32(1):44-51. PubMed
Chen, M. F., Shimada, F., Kato, H., Yano, S., and Kanaoka, M. Effect of oral administration of glycyrrhizin on the pharmacokinetics of prednisolone. Endocrinol Jpn 1991;38(2):167-174. PubMed
Lee, C. K., Park, K. K., Lim, S. S., Park, J. H., and Chung, W. Y. Effects of the licorice extract against tumor growth and cisplatin-induced toxicity in a mouse xenograft model of colon cancer. Biol Pharm Bull 2007;30(11):2191-2195. PubMed
Isaia, G. C., Pellissetto, C., Ravazzoli, M., and Tamone, C. Acute adrenal crisis and hypercalcemia in a patient assuming high liquorice doses. Minerva Med 2008;99(1):91-94.
Bocker, D. and Breithardt, G. [Induction of arrhythmia by licorice abuse]. Z Kardiol 1991;80(6):389-391.
Tacconi, P., Paribello, A., Cannas, A., and Marrosu, M. G. Carpal tunnel syndrome triggered by excessive licorice consumption. J Peripher.Nerv.Syst. 2009;14(1):64-65. PubMed
Tu, J. H., He, Y. J., Chen, Y., Fan, L., Zhang, W., Tan, Z. R., Huang, Y. F., Guo, D., Hu, D. L., Wang, D., and Hong-Hao Zhou. Effect of glycyrrhizin on the activity of CYP3A enzyme in humans. Eur J Clin Pharmacol 2010;66(8):805-810. PubMed
Goultschin, J., Palmon, S., Shapira, L., Brayer, L., and Gedalia, I. Effect of glycyrrhizin-containing toothpaste on dental plaque reduction and gingival health in humans. A pilot study. J Clin Periodontol 1991;18(3):210-212. PubMed
Scali, M., Pratesi, C., Zennaro, M. C., Zampollo, V., and Armanini, D. Pseudohyperaldosteronism from liquorice-containing laxatives. J Endocrinol Invest 1990;13(10):847-848. PubMed
Chatterjee, N., Domoto-Reilly, K., Fecci, P. E., Schwamm, L. H., and Singhal, A. B. Licorice-associated reversible cerebral vasoconstriction with PRES. Neurology 2010;75(21):1939-1941. PubMed
Imtiaz, K. E. Sweet root, bitter pill: liquorice-induced hyperaldosteronism. QJM 2011;104(12):1093-1095. PubMed
van Beers, E. J., Stam, J., and van den Bergh, W. M. Licorice consumption as a cause of posterior reversible encephalopathy syndrome: a case report. Crit Care 2011;15(1):R64. PubMed
MacKenzie, M. A., Hoefnagels, W. H., Jansen, R. W., Benraad, T. J., and Kloppenborg, P. W. The influence of glycyrrhetinic acid on plasma cortisol and cortisone in healthy young volunteers. J Clin Endocrinol Metab 1990;70(6):1637-1643. PubMed
Bardhan, K. D., Cumberland, D. C., Dixon, R. A., and Holdsworth, C. D. Clinical trial of deglycyrrhizinised liquorice in gastric ulcer. Gut 1978;19(9):779-782. PubMed
Koster, M. and David, G. K. Reversible severe hypertension due to licorice ingestion. N Engl J Med 1968;278(25):1381-1383. PubMed
Corse, F. M., Galgani, S., Gasparini, C., Giacanelli, M., and Piazza, G. Acute hypokalemic myopathy due to chronic licorice ingestion: report of a case. Ital J Neurol Sci 1983;4(4):493-497. PubMed
Berlango Jimenez A., Jimenez Murillo L., Montero Perez F. J., Munoz Avila J. A., Torres Murillo J., and Calderon de la Barca Gazquez J. M. [Acute rhabdomyolysis and tetraparesis secondary to hypokalemia due to ingested licorice]. An Med Interna 1995;12(1)
Bernardi, M., D'Intino, P. E., Trevisani, F., Cantelli-Forti, G., Raggi, M. A., Turchetto, E., and Gasbarrini, G. Effects of prolonged ingestion of graded doses of licorice by healthy volunteers. Life Sci 1994;55(11):863-872. PubMed
van der Zwan A. Hypertension encephalopathy after liquorice ingestion. Clin Neurol Neurosurg 1993;95(1):35-37. PubMed
Werner, S., Brismar, K., and Olsson, S. Hyperprolactinaemia and liquorice. Lancet 2-10-1979;1(8111):319.
Nishioka, K. and Seguchi, T. Contact allergy due to oil-soluble licorice extracts in cosmetic products. Contact Dermatitis 1999;40(1):56. PubMed
Yoshino T, Yanagawa T, Watanabe K. Risk factors for pseudoaldosteronism with rhabdomyolysis caused by consumption of drugs containing licorice and differences between incidence of these conditions in Japan and other countries: case report and literature r
Li G, Simmler C, Chen L, et al. Cytochrome P450 inhibition by three licorice species and fourteen licorice constituents. Eur J Pharm Sci. 2017;109:182-190. PubMed
Li J, Fan X, Wang Q. Hypertensive crisis with 2 target organ impairment induced by glycyrrhizin: a case report. Medicine (Baltimore) 2018;97(11):e0073. PubMed
Foster CA, Church KS, Poddar M, Van Uum SH, Spaic T. Licorice-induced hypertension: a case of pseudohyperaldosteronism due to jelly bean ingestion. Postgrad Med 2017;129(3):329-31. PubMed
Gallacher SD, Tsokolas G, Dimitropoulos I. Liquorice-induced apparent mineralocorticoid excess presenting in the emergency department. Clin Med (Lond) 2017;17(1):43-5. PubMed
Dai DW, Singh I, Hershman JM. Lozenge-induced hypermineralcorticoid state--a unique case of licorice lozenges resulting in hypertension and hypokalemia. J Clin Hypertens (Greenwich) 2016;18(2):159-60.
O'Connell K, Kinsella J, McMahon C, Holian J, O'Riordan S. Posterior reversible encephalopathy syndrome (PRES) associated with liquorice consumption. Ir J Med Sci 2016;185(4):945-7. PubMed
Hataya Y, Oba A, Yamashita T, Komatsu Y. Hyponatremia in an elderly patient due to isolated hypoaldosteronism occurring after licorice withdrawal. Intern Med 2017;56(2):175-9. PubMed
Ha Y, Wang T, Li J, et al. Herb-Drug Interaction Potential of Licorice Extract and Paclitaxel: A Pharmacokinetic Study in Rats. Eur J Drug Metab Pharmacokinet. 2020;45(2):257-264. PubMed
Edelman ER, Butala NM, Avery LL, Lundquist AL, Dighe AS. Case 30-2020: A 54-Year-Old Man with Sudden Cardiac Arrest. N Engl J Med. 2020;383(13):1263-1275. PubMed
Wang H, Dong L, Qu F, et al. Effects of glycyrrhizin on the pharmacokinetics of nobiletin in rats and its potential mechanism. Pharm Biol. 2020 Dec;58(1):352-356. PubMed
Attou R, Redant S, Honore PM, Preseau T, Hantson P, De Bels D. Liquorice intoxication can lead to cardiac arrest! Case Rep Emerg Med. 2020;2020:3727682. PubMed
Benge E, Shah P, Yamaguchi L, Josef V. Trick or Treat? Licorice-Induced Hypokalemia: A Case Report. Cureus 2020;12(11):e11656. PubMed
Abe K, Higurashi T, Takahashi M, et al. Concomitant Use of High-dose Methotrexate and Glycyrrhizin Affects Pharmacokinetics of Methotrexate, Resulting in Hepatic Toxicity. In Vivo 2021;35(4):2163-2169. PubMed
Awad N, Makar G, Burroughs V, Ravi P, Burroughs SR. Licorice-induced apparent mineralocorticoid excess causing persistent hypertension and hypokalemia. Acta Endocrinol (Buchar) 2020;16(4):508-510. PubMed
Patel P, Aknouk M, Dawson A, et al. How Much Is Too Much? Exploring Pseudohyperaldosteronism in Glycyrrhizic Acid Toxicity From Chronic Licorice Root Consumption. Cureus 2021;13(7):e16454. PubMed
Fan ZJ, Liu JM, Li XX, et al. Glycyrrhizin-Induced Pseudohyperaldosteronism: A Case Report. Chin J Integr Med 2022. PubMed
Gatica-Ortega ME, Pastor-Nieto MA. Allergic contact dermatitis to Glycyrrhiza inflata root extract in an anti-acne cosmetic product. Contact Dermatitis 2021;85(4):454-455.
Wang JB, Huang A, Wang Y, et al. Corticosteroid plus glycyrrhizin therapy for chronic drug- or herb-induced liver injury achieves biochemical and histological improvements: a randomised open-label trial. Aliment Pharmacol Ther 2022;55(10):1297-1310. PubMed
Puaratanaarunkon T, Washrawirul C, Chuenboonngarm N, Noppakun N, Asawanonda P, Kumtornrut C. Efficacy and safety of a facial serum containing snail secretion filtrate, Calendula officinalis, and Glycyrrhiza glaba root extract in the treatment of maskne: A
Haron MH, Dale O, Martin K, et al. Evaluation of the Herb-Drug Interaction Potential of Commonly Used Botanicals on the US Market with Regard to PXR- and AhR-Mediated Influences on CYP3A4 and CYP1A2. J Diet Suppl 2022. PubMed
Han EJ, Park JS. Lethal Arrhythmia Induced by Licorice. J Korean Med Sci 2023;38(12):e107. 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.

Pharmacist Counseling Corner

Taking Licorice and Levothyroxine, Liothyronine Together: Common Questions

Is it safe to take Licorice with Levothyroxine, Liothyronine?

We do not list a known interaction between Licorice 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 Licorice and Levothyroxine, Liothyronine combination checked?

Interactions in our licensed database are recorded against drug classes. Levothyroxine, Liothyronine is filed under 3 classifications, and Licorice has documented interactions with 18 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 Licorice interact with any other medications?

Yes. Licorice has 1,040 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 — Licorice 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

Licorice 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 92 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Levothyroxine, Liothyronine and Licorice?

Our pharmacists answer your medication & supplement questions — free.

Ask a pharmacist

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.