Drug & supplement interaction

Xanthan Gum + Levothyroxine

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

Minor Interaction
Medically reviewed by · Updated September 2026
The bottom line Minor

Xanthan Gum has a minor interaction with Levothyroxine. Theoretically, xanthan gum can alter the absorption of oral drugs due to its fiber qualities.

Read the full interaction report
SeverityMinor
LikelihoodPossible
EvidenceD
What do Severity, Likelihood & Evidence mean?
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Interaction report

Xanthan Gum and Levothyroxine

Here is the interaction we found between these two, with the evidence behind it.

Minor

ORAL DRUGS

Why this applies to Levothyroxine

Levothyroxine falls under ORAL DRUGS — the group Xanthan Gum interacts with.

Theoretically, xanthan gum can alter the absorption of oral drugs due to its fiber qualities. Xanthan gum slows gastric emptying and has been used to control the release of drugs in tablet formulations. To avoid any alterations in drug absorption, xanthan gum should be taken 30-60 minutes after oral medications.
Severity Minor Likelihood Possible Evidence D

Interaction has been documented in animal or in lab research, or the interaction has been documented in humans but is limited to case reports or conflicting clinical research exists.

Dr. Brian Staiger, PharmD, BCPS
Dr. Brian Staiger explains PharmD, Clinical Pharmacist

Here's the thing with levothyroxine: your body absorbs it best on an empty stomach, and it can be picky. Because xanthan gum is a soluble fiber that turns into a thick gel and slows how fast your stomach empties, the worry is that it could trap a little of your thyroid pill and keep some of it from being absorbed. If that happens, you might get a slightly weaker dose, which over time could let symptoms like fatigue, feeling cold, weight gain, or constipation creep back in.

I want to be clear, though: this is a theoretical concern based on how fiber behaves, not something proven to cause problems. To play it safe, separate them. Take your levothyroxine first, then wait 30 to 60 minutes before any xanthan gum. If you're using it regularly, check with your pharmacist or doctor.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Osilesi O, Trout DL, Glover EE, et al. Use of xanthan gum in dietary management of diabetes mellitus. Am J Clin Nutr 1985;42: 597-603. PubMed
  2. Beneke CE, Viljoen AM, Hamman JH. Polymeric plant-derived excipients in drug delivery. Molecules. 2009;14(7):2602-20. PubMed

What These Ratings Mean

Every interaction above is graded three ways — here’s the key to each label.

Severity how clinically significant the interaction is
Major

Clinically significant. Avoid the combination, or use only under close professional supervision.

Moderate

Usually worth avoiding or managing — may need monitoring, a dose change, or timing apart.

Minor

Generally not serious. Be aware of it and mention it to your pharmacist.

Likelihood how strong the evidence is that the interaction actually happens in people
  • LikelyWell-controlled human studies have demonstrated the likely existence of this interaction.
  • ProbableInteraction has not been documented in well-controlled studies, however, the interaction has been demonstrated in some small human studies or in controlled animal studies in conjunction with multiple case reports.
  • PossibleInteraction has been documented in animal or in lab research, or the interaction has been documented in humans but is limited to case reports or conflicting clinical research exists.
  • UnlikelyInteraction has been demonstrated in animal or in lab research but has been shown not to occur in humans.
Evidence the quality of the studies behind the rating (graded A–D)
  • AHigh-quality meta-analysis (quantitative systematic review).
  • BCase-control study.
  • CConsensus.
  • DAnecdotal evidence.

These ratings are for information only. Never start, stop, or otherwise change your therapy before speaking with your provider.

Keep it in perspective

Xanthan Gum Also Interacts With Other Medications

Xanthan Gum has 2,021 minor known drug interactions in our database — the Levothyroxine one above is one of them. If you take anything else, check it against the full list below.

Minor 2,021 No known interaction 809 (incl. Levothyroxine)
Taking anything else?

Check Another of Your Medications Against Xanthan Gum

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

From our Q&A

Questions About Xanthan Gum 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 Xanthan Gum 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 Xanthan Gum 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 Xanthan Gum as Part of a Dietary Supplement Product? Check It for Interactions

We hold 260 real supplement products containing Xanthan Gum, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Xanthan Gum. Your product may carry other ingredients that interact with Levothyroxine too, on top of Xanthan Gum — and those would not show on this page. Find your product and we’ll check every ingredient on its label:

How much people look this up

Where Xanthan Gum 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 Xanthan Gum
Top half

#525 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.

Supplement

About Xanthan Gum

What is Xanthan Gum?

Xanthan Gum
  • Food thickener and stabilizer
  • Bulk-forming laxative
  • Thickening liquids for swallowing problems
  • Gluten-free baking aid
  • Blood sugar support (limited evidence)

Xanthan gum is a fermentation-made fiber widely used to thicken and stabilize foods and to thicken liquids for people with swallowing difficulties. It is generally recognized as safe in the small amounts found in food, but large doses can cause gas, bloating, and loose stools. Talk to your pharmacist or doctor before using it for any medical purpose.

Read the full Xanthan Gum 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 & Xanthan Gum

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

0Major
0Moderate
2,021Minor
808No known interaction
2,021 Minor 808 No interaction
Minor

2,021 interactions

Showing 60 of 2,021 minor interactions — see all 2,021 on the Xanthan Gum page.

No interaction 808 drugs checked — show the list

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

Showing the 60 most looked-up of 808 medications checked with no known interaction — see the full Xanthan Gum list.

See the full Xanthan Gum interactions page
See every supplement checked against Levothyroxine, ranked by severity
Sources

Sources & How We Checked

Interaction details are evidence-graded and sourced from the Natural Medicines database. The medication overview comes from MedlinePlus.

Content is written and reviewed by licensed HelloPharmacist pharmacists. See our data sources and editorial standards for how this information is built and checked.

Parts of this content are provided by the Therapeutic Research Center, LLC.

DISCLAIMER: Currently this does not check for drug-drug interactions. This is not an all-inclusive comprehensive list of potential interactions and is for informational purposes only. Not all interactions are known or well-reported in the scientific literature, and new interactions are continually being reported. Input is needed from a qualified healthcare provider including a pharmacist before starting any therapy. Application of clinical judgment is necessary.

© 2021 Therapeutic Research Center, LLC

Keep exploring
Xanthan Gum monograph › Uses, safety, and every drug interaction in one place Levothyroxine supplement interactions › Every supplement checked against Levothyroxine, ranked by severity Levothyroxine drug information › The full plain-English guide to this medication Supplement interaction checker › Check any supplement or product against your medications Browse medications A–Z › Every drug we've checked against herbs & supplements Ask a pharmacist › Free, personal answer from our licensed team
Pharmacist Counseling Corner

Taking Xanthan Gum and Levothyroxine Together: Common Questions

Can you take Xanthan Gum with Levothyroxine?
There is only a minor interaction, which is usually not serious. Read the full details on this page and confirm with your pharmacist before combining them.
How serious is the Xanthan Gum and Levothyroxine interaction?
We rate it Minor. This interaction is generally not clinically significant, but it remains worth noting and discussing with your pharmacist.

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

Still Have a Question About Levothyroxine and Xanthan Gum?

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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.