Lactoferrin + Levothyroxine
Levothyroxine brand names: Euthyrox, Levothroid, Unithroid, Synthroid, Levoxyl, and others.
We found no known interaction between Lactoferrin 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.
Lactoferrin 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 Lactoferrin 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.
Worth understanding: our licensed dataset holds no drug-interaction record for Lactoferrin at all — not against Levothyroxine, and not against any other medication we track. This verdict therefore rests on the absence of any recorded data, not on research that looked at this combination and found nothing. We cannot rule an interaction out.
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.
Lactoferrin safety at a glance
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.
Lactoferrin in Pregnancy & Breastfeeding
When used orally in amounts commonly found in foods. Lactoferrin has Generally Regarded as Safe (GRAS) status in the US.
When used orally in medicinal amounts. Lactoferrin has been used with apparent safety during the second or third trimester of pregnancy at doses of up to 250 mg daily for up to 8 weeks. Also, bovine lactoferrin has been used with apparent safety throughout all trimesters of pregnancy at doses of up to 200 mg daily. There is insufficient reliable information available about the safety of intravaginal lactoferrin during pregnancy and lactation; avoid using.
When used orally in amounts commonly found in foods. Lactoferrin has Generally Regarded as Safe (GRAS) status in the US. There is insufficient reliable information available about the safety of lactoferrin when used medicinally during lactation; 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
Some Levothyroxine Products Have a Food Rule — Lactoferrin Should Not Break It
At least one FDA label for a product containing Levothyroxine says to take it on an empty stomach. Most supplements — Lactoferrin 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 Lactoferrin 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.
Questions About Lactoferrin 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 Lactoferrin 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:
- Black Currant Oil With Levothyroxine, Methotrexate, and a Statin ›
- Provitalize With Levothyroxine, Valacyclovir, and Citalopram ›
- Can I Drink Essiac Tea With My Blood Pressure and Thyroid Meds? ›
Not quite your question? Ask our pharmacists directly — it is free, there is no account required, and answers usually come back within 24 hours.
See Every Supplement That Interacts With Levothyroxine
This page covers Lactoferrin 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
Taking Lactoferrin as Part of a Dietary Supplement Product? Check It for Interactions
We hold 292 real supplement products containing Lactoferrin, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Lactoferrin. Even though Lactoferrin 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:
Where Lactoferrin 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.
#535 of 1,452 supplements looked up here in the last 7 days
#2 of 2,830 medications looked up here in the last 7 days
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 Lactoferrin reference on this page ↓
- Freshness: we automatically re-check this combination every week — this pair was last verified September 13, 2026. The Lactoferrin 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.
About Lactoferrin
What is Lactoferrin?
- Iron deficiency and anemia support
- Immune support
- Gut health
- Stomach (H. pylori) infection
- Acne
- Diarrhea prevention in infants
Lactoferrin is an iron-binding protein found naturally in milk and other body fluids, and supplements are usually made from cow's milk or rice. It is being studied for immune support, iron levels, gut health, and infections, but the evidence is still limited and mixed for most uses. It is generally well tolerated, but talk with a pharmacist or doctor before starting it.
Protein from milk (colostrum), or made with recombinant technology · Capsules, tablets, powders; also added to some infant formulas and functional foods
An interaction check asks whether these two react with each other — it does not ask whether Lactoferrin is a good idea for someone in your situation. Here is what our Lactoferrin record says about it on its own.
Lactoferrin: dosing
There is no official standardized dose of lactoferrin, and the right amount can depend on the product, the form, and the reason for use. Doses used in research have varied widely.The best approach is to follow the directions on the product label and not exceed the recommended amount.
From our Lactoferrin monograph — the full record covers uses, side effects and every documented interaction.
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.
Other Drugs & Lactoferrin
Browse every other medication we’ve checked against Lactoferrin — both the ones with a known interaction and the ones without. Select any drug for the full detail.
No drugs match “”.
No interaction 2,829 drugs checked — show the list
We also checked Lactoferrin against these medications and found no known interaction in our sources. Open any page to confirm.
- Apixaban ›
- Amlodipine ›
- Methylphenidate ›
- Warfarin ›
- Sertraline ›
- Testosterone ›
- Losartan Potassium ›
- Metoprolol ›
- Aspirin ›
- Ivermectin ›
- Rivaroxaban ›
- Rosuvastatin ›
- Escitalopram ›
- Tadalafil ›
- Acetaminophen ›
- Clopidogrel ›
- Valacyclovir ›
- Atorvastatin ›
- Docusate ›
- Hydroxyurea ›
- Abemaciclib ›
- Methamphetamine ›
- Ibuprofen ›
- Sumatriptan ›
- Semaglutide ›
- Tirzepatide ›
- Warfarin Sodium ›
- Prednisone ›
- Propranolol ›
- Lisdexamfetamine ›
- Acyclovir ›
- Bupropion ›
- Metformin ›
- Amoxicillin ›
- Lisinopril ›
- Bendamustine ›
- Amitriptyline ›
- Doxycycline ›
- Lamotrigine ›
- Fluoxetine ›
- Methotrexate ›
- Acetaminophen, Codeine ›
- Gabapentin ›
- Amphetamine ›
- Pregabalin ›
- Isotretinoin ›
- Dextroamphetamine ›
- Azithromycin ›
- Clonazepam ›
- Quetiapine ›
- Omeprazole ›
- Amlodipine Besylate ›
- Methylene Blue ›
- Duloxetine ›
- Letrozole ›
- Buspirone ›
- Citalopram ›
- Ciprofloxacin ›
- Naproxen ›
- Bisoprolol ›
Showing the 60 most looked-up of 2,829 medications checked with no known interaction — see the full Lactoferrin list.
Lactoferrin References
The 6 references that drive our Lactoferrin 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.
- Food and Drug Administration, CFSAN/Office of Food Additive Safety. Agency Response Letter GRAS Notice No. GRN 000130. 2003. Available at: http://www.cfsan.fda.gov/~rdb/opa-g130.html (Accessed 29 June 2005).
- Okada S, Tanaka K, Sato T, et al. Dose-response trial of lactoferrin in patients with chronic hepatitis C. Jpn J Cancer Res 2002;93:1063-9. PubMed
- Abu Hashim H, Foda O, Ghayaty E. Lactoferrin or ferrous salts for iron deficiency anemia in pregnancy: A meta-analysis of randomized trials. Eur J Obstet Gynecol Reprod Biol. 2017;219:45-52. PubMed
- Tarnow-Mordi WO, Abdel-Latif ME, Martin A, et al. The effect of lactoferrin supplementation on death or major morbidity in very low birthweight infants (LIFT): a multicentre, double-blind, randomised controlled trial. Lancet Child Adolesc Health. 2020 Jun PubMed
- ELFIN trial investigators group. Enteral lactoferrin supplementation for very preterm infants: a randomised placebo-controlled trial. Lancet. 2019 Feb 2;393(10170):423-433. doi: 10.1016/S0140-6736(18)32221-9.
- Lepanto MS, Rosa L, Cutone A, Conte MP, Paesano R, Valenti P. Efficacy of lactoferrin oral administration in the treatment of anemia and anemia of inflammation in pregnant and non-pregnant women: An interventional study. Front Immunol. 2018 Sep 21;9:2123. 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.
Taking Lactoferrin and Levothyroxine Together: Common Questions
Is it safe to take Lactoferrin with Levothyroxine?
Do Lactoferrin and Levothyroxine have any of the same side effects?
Should I take Lactoferrin and Levothyroxine at the same time of day?
Does Levothyroxine interact with any supplements?
Written and reviewed by the HelloPharmacist editorial staff. Our editorial policy
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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.