Drug & supplement interaction

Kaolin + Levothyroxine

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

No Known Interaction
The bottom line No known interaction

We found no known interaction between Kaolin 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.

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Interaction report

Kaolin 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 Kaolin 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.

Kaolin safety at a glance

Kaolin overall Use caution Generally considered low-risk for short-term use, but long-term or excessive use is not well studied.
Pregnancy Likely Safe When used orally in food amounts. Kaolin has Generally Recognized as Safe (GRAS) status in the US. Read the full pregnancy detail
Breastfeeding Likely Safe When used orally in food amounts. Kaolin has Generally Recognized as Safe (GRAS) status in the US. Read the full breastfeeding detail

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 and Kaolin? 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. Kaolin has documented interactions with 4 drug classes — the most serious being clindamycin (cleocin) (moderate), digoxin (lanoxin) (moderate) and quinidine (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

Kaolin Does Interact With Other Medications

Kaolin has 7 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.

Taking anything else?

Check Another of Your Medications Against Kaolin

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

What to actually watch for

No Interaction Found — But Data Suggests Kaolin and Levothyroxine May Share Several of the Same Side Effects

This is not an interaction. Neither one changes how your body handles the other, and nothing here says they react together. What our sources do show is that each has separately been linked to the effects below — so taking both can make those effects more likely to turn up, and harder to pin on one or the other if they do.

  • Stomach pain / Headache Additional detail

    Kaolin

    “Orally, kaolin can cause constipation, particularly in children and the elderly (15). When consumed in large quantities, kaolin can cause intestinal obstruction, which can be fatal in severe cases. It can also interfere with absorption of nutrients.”

    Kaolin · Natural Medicines adverse-effect record, reported in anemia.

    4 sources cited
    1. 15. McEvoy GK, ed. AHFS Drug Information. Bethesda, MD: American Society of Health-System Pharmacists, 1998.
    2. 101216. Dokoupil M, Marecová K, Handlos P, Brezina P. Death of a female prostitute due to intestinal obstruction by an unknown substance. J Forensic Sci 2019;64(1):289-91. doi: 10.1111/1556-4029.13824. PubMed
    3. 101218. Pain S, Fauconneau B, Bouquet E, Vasse-Terrier L, Pérault-Pochat MC. Severe craving associated with kaolin consumption. Eat Weight Disord 2019;24(2):379-81. doi: 10.1007/s40519-018-0583-1. PubMed
    4. 105862. Attarha BO, Mikulic S, Harris C, Scolapio JS. Kaolin Clay Anemia. Cureus 2021;13(3):e13796.

    Levothyroxine

    Listed in the ADVERSE REACTIONS section of the FDA label for Levothyroxine. Read the label on DailyMed ›

Reported for Kaolin but not commonly for Levothyroxine: a bowel blockage, dizziness, constipation and fainting.

Effects for Levothyroxine come from the ADVERSE REACTIONS section of its FDA label; effects for Kaolin come from the Natural Medicines adverse-effect record, quoted above. Wording is matched across sources by our own clinical vocabulary, so treat this as a prompt to pay attention, not a diagnosis.

Special populations

Kaolin in Pregnancy & Breastfeeding

Pregnancy And Lactation Likely Safe

When used orally in food amounts. Kaolin has Generally Recognized as Safe (GRAS) status in the US.

Pregnancy And Lactation Possibly Safe

When used orally as kaolin-pectin in appropriate amounts.

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

How to take them

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

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

How much people look this up

Where Kaolin 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 Kaolin
Steady interest

#1,201 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 Kaolin reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 13, 2026. The Kaolin 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 Kaolin

What is Kaolin?

Kaolin
  • Diarrhea
  • Upset stomach and nausea
  • Skincare and facial masks
  • Soothing minor skin irritation
  • Excessive salivation (traditional)

Kaolin is a soft, white clay mineral that has long been used in antidiarrheal products and skincare because it absorbs water and binds substances in the gut. Older diarrhea products often combined it with pectin, but modern guidelines favor rehydration and other treatments, and high-quality evidence for kaolin alone is limited. It is generally considered low-risk for short-term use, but check with your pharmacist or doctor before use, especially during pregnancy or breastfeeding.

Mineral clay (hydrated aluminum silicate) · Oral suspensions, tablets, powders, topical pastes and masks

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

Kaolin: dosing

There is no single official supplement dose for kaolin, and products vary widely in strength and formulation. The best approach is to follow the directions on the product label exactly.Do not exceed the recommended amount or use it for longer than directed without medical advice.

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

Read the full Kaolin 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 & Kaolin

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

0Major
7Moderate
0Minor
2,822No known interaction
Moderate

7 interactions

No interaction 2,822 drugs checked — show the list
Evidence & sources

Kaolin References

The 18 references that drive our Kaolin 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. McEvoy GK, ed. AHFS Drug Information. Bethesda, MD: American Society of Health-System Pharmacists, 1998.
  2. Barker G, Loftus L, Cuddy P, Barker B. The effects of sucralfate suspension and diphenhydramine syrup plus kaolin-pectin on radiotherapy-induced mucositis. Oral Surg Oral Med Oral Pathol 1991;71:288-93.
  3. Carnel SB, Blakeslee DB, Oswald SG, Barnes M. Treatment of radiation- and chemotherapy-induced stomatitis. Otolaryngol Head Neck Surg 1990;102:326-30.
  4. Levin JL, Frank AL, Williams MG, et al. Kaolinosis in a cotton mill worker. Am J Ind Med 1996;29:215-21.
  5. Chaudhary BA, Kanes GJ, Pool WH. Pleural thickening in mild kaolinosis. South Med J 1997;90:1106-9.
  6. Altekruse EB, Chaudhary BA, Pearson MG, Morgan WK. Kaolin dust concentrations and pneumoconiosis at a kaolin mine. Thorax 1984;39:436-41.
  7. Rodin SM, Johnson BF. Pharmacokinetic interactions with digoxin. Clin Pharmacokinet 1988;15:227-44.
  8. Babhair SA, Tariq M. Effect of magnesium trisilicate and kaolin-pectin on the bioavailability of trimethoprim. Res Commun Chem Pathol Pharmacol 1983;40:165-8.
  9. Bucci AJ, Myre SA, Tan HS, Shenouda LS. In vitro interaction of quinidine with kaolin and pectin. J Pharm Sci 1981;70:999-1002.
  10. Allen MD, Greenblatt DJ, Harmatz JS, Smith TW. Effect of magnesium-aluminum hydroxide and kaolin-pectin on absorption of digoxin from tablets and capsules. J Clin Pharmacol 1981;21:26-30. PubMed
  11. Albert KS, Ayres JW, DiSanto AR, et al. Influence of kaolin-pectin suspension on digoxin bioavailability. J Pharm Sc 1978;67:1582-6.
  12. Albert KS, et al. Pharmacokinetic evaluation of a drug interaction between kaolin-pectin and clindamycin. J Pharm Sci 1978 67:1579-82.
  13. Electronic Code of Federal Regulations. Title 21. Part 182 -- Substances Generally Recognized As Safe. Available at: https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfcfr/CFRSearch.cfm?CFRPart=182
  14. Black RA, Hill DA. Over-the-counter medications in pregnancy. Am Fam Physician 2003;67:2517-24.
  15. Electronic Code of Federal Regulations. Title 21. Part 335 - Antidiarrheal drug products for over-the-counter human use. Available at: https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfcfr/CFRSearch.cfm?fr=335.50

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 Kaolin and Levothyroxine Together: Common Questions

Is it safe to take Kaolin with Levothyroxine?
We do not list a known interaction between Kaolin 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.
Do Kaolin and Levothyroxine have any of the same side effects?
Yes — our sources link each of them separately to 2 of the same effects. That is not an interaction: neither changes how your body handles the other. It does mean that if one of those effects turns up, it can be harder to tell which one is behind it. They are listed on this page with the source behind each.
Should I take Kaolin 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 Kaolin 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 Kaolin and Levothyroxine combination checked?
Interactions in our licensed database are recorded against drug classes. Levothyroxine is filed under 3 classifications, and Kaolin has documented interactions with 4 drug classes — 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 Kaolin interact with any other medications?
Yes. Kaolin has 7 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 — Kaolin 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

Still Have a Question About Levothyroxine and Kaolin?

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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.