Drug & supplement interaction

Limosilactobacillus Fermentum + 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 Limosilactobacillus Fermentum 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

Limosilactobacillus Fermentum 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 Limosilactobacillus Fermentum 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.

Limosilactobacillus Fermentum safety at a glance

Limosilactobacillu... overall Use caution Generally well tolerated in healthy people, but evidence and quality vary by product and strain.
Pregnancy Use caution Some strains have been studied in pregnancy, but safety is not firmly established, so check with your doctor first.
Breastfeeding Possibly Safe When used orally and appropriately. Limosilactobacillus fermentum CECT5716 has been used with apparent safety when breastfeeding for up to 16 weeks. 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 Limosilactobacillus Fermentum? 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. Limosilactobacillus Fermentum has documented interactions with 1 drug class — the most serious being antibiotic 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

Limosilactobacillus Fermentum Does Interact With Other Medications

Limosilactobacillus Fermentum has 182 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 182 No known interaction 2,648 (incl. Levothyroxine)
Taking anything else?

Check Another of Your Medications Against Limosilactobacillus Fermentum

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

What to actually watch for

What Limosilactobacillus Fermentum Itself Has Been Linked To

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

  • A higher chance of infection Worth acting on Additional detail

    “Since Limosilactobacillus fermentum preparations contain live and active microorganisms, there is some concern that they might cause pathogenic infection in some patients. Some lactobacilli species have been isolated in cases of bacteremia, sepsis, splenic abscess, endocarditis, necrotizing fasciitis, pancreatic necrosis, and meningoencephalitis.”

    Limosilactobacillus Fermentum · Natural Medicines adverse-effect record, reported in sepsis.

    6 sources cited
    1. 107543. Rossi F, Amadoro C, Gasperi M, Colavita G. Lactobacilli infection case reports in the last three years and safety implications. Nutrients. 2022;14(6):1178. PubMed
    2. 110917. Ranchal P, Gupta R, Goldberg R, A Lobo S, Pascual A, El Khoury MY. Penicillin-sensitive Lactobacillus jensenii bacteremia. Am J Ther 2021;28(2):e250-e252. PubMed
    3. 110918. Grazioli-Gauthier L, Rigamonti E, Leo LA, Martinetti Lucchini G, Lo Priore E, Bernasconi E. Lactobacillus jensenii mitral valve endocarditis: Case report, literature review and new perspectives. IDCases 2022;27:e01401. PubMed
    4. 110920. Toprak NU, Bozan T, Yilmaz S, Buyukbayrak EE, Tigen ET. Polymicrobial bacteremia due to Lactobacillus jensenii and Veillonella montpellierensis in a pregnant patient; case report and review of literature. Anaerobe 2022;75:102576. PubMed
    5. 110921. Chazan B, Raz R, Shental Y, Sprecher H, Colodner R. Bacteremia and pyelonephritis caused by Lactobacillus jensenii in a patient with urolithiasis. Isr Med Assoc J 2008;10(2):164-5.
    6. 112565. Achuthanandan S, Dhaliwal A, Lu T, Sharma K. Brain abscess due to Lactobacillus fermentum in an uncontrolled diabetic. Cureus 2022;14(6):e26360. PubMed
  • Stomach upset Additional detail

    Recorded for Limosilactobacillus Fermentum in the same Natural Medicines adverse-effect record shown under A higher chance of infection above.

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

Special populations

Limosilactobacillus Fermentum in Pregnancy & Breastfeeding

Lactation Possibly Safe

When used orally and appropriately. Limosilactobacillus fermentum CECT5716 has been used with apparent safety when breastfeeding for up to 16 weeks.

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 — Limosilactobacillus Fermentum Should Not Break It

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

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

About Limosilactobacillus Fermentum

What is Limosilactobacillus Fermentum?

  • Digestive health
  • Immune support
  • Vaginal and urinary health
  • Cholesterol support
  • Oral health

Limosilactobacillus fermentum (formerly Lactobacillus fermentum) is a probiotic bacterium found in fermented foods and the human body, used to support gut, immune, and women's health. Early research is promising for some uses but most evidence is preliminary, and effects can differ by strain. It is generally well tolerated in healthy people, but talk to your pharmacist or doctor before starting, especially if your immune system is weak.

Limosilactobacillus fermentum · Lactobacillaceae · Whole live bacteria (probiotic strain) · Capsules, tablets, powders, fermented foods, and combination probiotic products

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

Limosilactobacillus Fermentum: dosing

There is no official standardized dose for Limosilactobacillus fermentum. Probiotic amounts are usually measured in colony-forming units (CFU), and the right amount depends on the strain and the product.The best approach is to follow the directions on the product label. Do not assume more is better.

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

Read the full Limosilactobacillus Fermentum 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 & Limosilactobacillus Fermentum

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

0Major
182Moderate
0Minor
2,647No known interaction
182 Moderate 2,647 No interaction
Moderate

182 interactions

Showing 60 of 182 moderate interactions — see all 182 on the Limosilactobacillus Fermentum page.

No interaction 2,647 drugs checked — show the list

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

Showing the 60 most looked-up of 2,647 medications checked with no known interaction — see the full Limosilactobacillus Fermentum list.

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

Limosilactobacillus Fermentum References

The 12 references that drive our Limosilactobacillus Fermentum 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. Pierce A. The American Pharmaceutical Association Practical Guide to Natural Medicines. New York: The Stonesong Press, 1999:19.
  2. Rossi F, Amadoro C, Gasperi M, Colavita G. Lactobacilli infection case reports in the last three years and safety implications. Nutrients. 2022;14(6):1178. PubMed
  3. Ranchal P, Gupta R, Goldberg R, A Lobo S, Pascual A, El Khoury MY. Penicillin-sensitive Lactobacillus jensenii bacteremia. Am J Ther 2021;28(2):e250-e252. PubMed
  4. Grazioli-Gauthier L, Rigamonti E, Leo LA, Martinetti Lucchini G, Lo Priore E, Bernasconi E. Lactobacillus jensenii mitral valve endocarditis: Case report, literature review and new perspectives. IDCases 2022;27:e01401. PubMed
  5. Toprak NU, Bozan T, Yilmaz S, Buyukbayrak EE, Tigen ET. Polymicrobial bacteremia due to Lactobacillus jensenii and Veillonella montpellierensis in a pregnant patient; case report and review of literature. Anaerobe 2022;75:102576. PubMed
  6. Chazan B, Raz R, Shental Y, Sprecher H, Colodner R. Bacteremia and pyelonephritis caused by Lactobacillus jensenii in a patient with urolithiasis. Isr Med Assoc J 2008;10(2):164-5.
  7. Achuthanandan S, Dhaliwal A, Lu T, Sharma K. Brain abscess due to Lactobacillus fermentum in an uncontrolled diabetic. Cureus 2022;14(6):e26360. PubMed
  8. Pastor-Villaescusa B, Hurtado JA, Gil-Campos M, et al. Effects of Lactobacillus fermentum CECT5716 Lc40 on infant growth and health: a randomised clinical trial in nursing women. Benef Microbes 2020;11(3):235-244. PubMed
  9. Jiménez-Gutiérrez JM, Peláez-Luna M, Campos-Murguía A. A rare case of emphysematous gastritis caused by Lactobacillus fermentum in a patient with diabetes. Rev Esp Enferm Dig 2021;113(9):670-671. PubMed
  10. Greig JR, Eltringham IJ, Birthistle K. Primary peritonitis due to Lactobacillus fermentum. J Infect 1998;36(2):242-3. PubMed
  11. Woo PC, Lau SK, Lin AW, Curreem SO, Fung AM, Yuen KY. Surgical site abscess caused by Lactobacillus fermentum identified by 16S ribosomal RNA gene sequencing. Diagn Microbiol Infect Dis 2007;58(2):251-4. PubMed
  12. Gallemore GH, Mohon RT, Ferguson DA. Lactobacillus fermentum endocarditis involving a native mitral valve. J Tenn Med Assoc 1995;88(8):306-8.

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 Limosilactobacillus Fermentum and Levothyroxine Together: Common Questions

Is it safe to take Limosilactobacillus Fermentum with Levothyroxine?
We do not list a known interaction between Limosilactobacillus Fermentum 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 Limosilactobacillus Fermentum 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 Limosilactobacillus Fermentum 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 Limosilactobacillus Fermentum and Levothyroxine combination checked?
Interactions in our licensed database are recorded against drug classes. Levothyroxine is filed under 3 classifications, and Limosilactobacillus Fermentum 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 Limosilactobacillus Fermentum interact with any other medications?
Yes. Limosilactobacillus Fermentum has 182 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 — Limosilactobacillus Fermentum 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

Limosilactobacillus Fermentum 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 12 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

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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.