Drug & supplement interaction

Saigon Cinnamon + Levothyroxine

Levothyroxine brand names: Euthyrox, Levothroid, Unithroid, Synthroid, Levoxyl, and others.

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 Saigon Cinnamon 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.

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Interaction report

Saigon Cinnamon 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 Saigon Cinnamon 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.

Saigon Cinnamon safety at a glance

Saigon Cinnamon overall Use caution Generally safe as a food spice, but large supplement doses raise concerns mainly due to its high coumarin content.
Pregnancy Use caution Food amounts are likely fine, but avoid medicinal or supplement doses during pregnancy due to limited safety data.
Breastfeeding Use caution Food amounts are likely fine, but avoid concentrated supplement doses because safety has not been studied.

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

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

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. Saigon Cinnamon has documented interactions with 1 drug class — the most serious being hepatotoxic drugs (moderate) — 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.

Keep it in perspective

Saigon Cinnamon Does Interact With Other Medications

Saigon Cinnamon has 370 moderate known drug interactions in our database — Levothyroxine isn’t one of them. If you take anything else, check it against the full list below.

Moderate 370 No known interaction 2,460 (incl. Levothyroxine)
Taking anything else?

Check Another of Your Medications Against Saigon Cinnamon

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

What to actually watch for

What Saigon Cinnamon Itself Has Been Linked To

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

  • Liver problems Worth acting on Additional detail

    “There is some concern about the safety of ingesting large amounts of Saigon cinnamon for extended durations due to its coumarin content. Saigon cinnamon contains higher levels of coumarin than other cinnamon species. In humans, very high doses of coumarin from 50-7000 mg daily can result in hepatotoxicity that resolves when coumarin is discontinued.”

    Saigon Cinnamon · Natural Medicines adverse-effect record, reported in myasthenia gravis.

    2 sources cited
    1. 92558. Wang YH, Avula B, Nanayakkara NP, Zhao J, Khan IA. Cassia cinnamon as a source of coumarin in cinnamon-flavored food and food supplements in the United States. J Agric Food Chem. 2013;61(18):4470-6. PubMed
    2. 15302. Felter SP, Vassallo JD, Carlton BD, Daston GP. A safety assessment of coumarin taking into account species-specificity of toxicokinetics. Food Chem Toxicol 2006;44:462-75. PubMed

Everything above comes from the Natural Medicines adverse-effect record for Saigon Cinnamon — expand a row for the licensed statement it rests on. We read the ADVERSE REACTIONS section of Levothyroxine’s FDA label too, and the two lists don’t meaningfully overlap — which is why no Levothyroxine column appears here.

How to take them

Some Levothyroxine Products Have a Food Rule — Saigon Cinnamon Should Not Break It

At least one FDA label for a product containing Levothyroxine says to take it on an empty stomach. Most supplements — Saigon Cinnamon 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 Saigon Cinnamon 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.

From our Q&A

Questions About Saigon Cinnamon 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 Saigon Cinnamon 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:

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

This page covers Saigon Cinnamon 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

Open the Levothyroxine interaction page

One more smart check

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

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

How much people look this up

Where Saigon Cinnamon 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.

Supplement Saigon Cinnamon
Steady interest

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

29 days ago today
Medication Levothyroxine
Top 10

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

What is Saigon Cinnamon?

  • Blood sugar support
  • Digestive upset
  • Antioxidant support
  • Flavoring and culinary use
  • Antimicrobial

Saigon cinnamon is a flavorful spice from a Cinnamomum tree grown mainly in Vietnam, and it is a type of 'cassia' cinnamon. Some people use it for blood sugar and digestion, but the human evidence is limited. Because cassia cinnamons like this one are high in a compound called coumarin, regularly taking large supplement doses may be hard on the liver in sensitive people, so use food amounts and check with your pharmacist before taking concentrated products.

Cinnamomum loureiroi · Lauraceae · Inner bark (and bark essential oil) · Ground spice, sticks (quills), capsules, extracts, tea, essential oil

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

Saigon Cinnamon: dosing

There is no well-established standardized dose for Saigon cinnamon, and product strengths vary widely. Studies on cinnamon have used different amounts and forms, making it hard to recommend a single reliable dose.If you choose to use a supplement, the safest approach is to follow the directions on the product label and not exceed them.

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

Read the full Saigon Cinnamon monograph & all interactions
Medication

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.

See full Levothyroxine drug information
Keep checking

Other Drugs & Saigon Cinnamon

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

0Major
370Moderate
0Minor
2,459No known interaction
370 Moderate 2,459 No interaction
Moderate

370 interactions

Showing 60 of 370 moderate interactions — see all 370 on the Saigon Cinnamon page.

No interaction 2,459 drugs checked — show the list

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

Showing the 60 most looked-up of 2,459 medications checked with no known interaction — see the full Saigon Cinnamon list.

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

Saigon Cinnamon References

The 4 references that drive our Saigon Cinnamon 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. Press release. Cinnamon capsules to reduce blood sugar are medicinal products! Efficacy has not been scientifically proven - some products contain high levels of coumarin. Federal Institute of Risk Assessment (BfM), Germany, November 11, 2006. Available a
  2. Felter SP, Vassallo JD, Carlton BD, Daston GP. A safety assessment of coumarin taking into account species-specificity of toxicokinetics. Food Chem Toxicol 2006;44:462-75. PubMed
  3. Choi, J., Lee, K. T., Ka, H., Jung, W. T., Jung, H. J., and Park, H. J. Constituents of the essential oil of the Cinnamomum cassia stem bark and the biological properties. Arch Pharm Res 2001;24(5):418-423.
  4. Wang YH, Avula B, Nanayakkara NP, Zhao J, Khan IA. Cassia cinnamon as a source of coumarin in cinnamon-flavored food and food supplements in the United States. J Agric Food Chem. 2013;61(18):4470-6. 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 Saigon Cinnamon and Levothyroxine Together: Common Questions

Is it safe to take Saigon Cinnamon with Levothyroxine?
We do not list a known interaction between Saigon Cinnamon and Levothyroxine. 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.
Should I take Saigon Cinnamon and Levothyroxine at the same time of day?
At least one FDA label for a product containing Levothyroxine says to take it on an empty stomach, and supplements are usually taken with a meal — so taking them together at breakfast is the easy mistake. Where that applies, keep Levothyroxine on its own and move Saigon Cinnamon to a meal later in the day. Food instructions belong to the product rather than the ingredient, so check the directions on your own box. This is about absorption, not an interaction.
How was the Saigon Cinnamon and Levothyroxine combination checked?
Interactions in our licensed database are recorded against drug classes. Levothyroxine is filed under 3 classifications, and Saigon Cinnamon has documented interactions with 1 drug class — none of Levothyroxine'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 Saigon Cinnamon interact with any other medications?
Yes. Saigon Cinnamon has 370 documented drug interactions in our database — Levothyroxine 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 interact with any supplements?
Yes. Levothyroxine has documented interactions with 50 supplements in our database — Saigon Cinnamon is not one of them. The Levothyroxine 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

Saigon Cinnamon monograph Uses, safety profile, and every drug interaction in one place Levothyroxine drug information The full plain-English guide to this medication Levothyroxine supplement interactions Every supplement checked against Levothyroxine, 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 4 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Levothyroxine and Saigon Cinnamon?

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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.