Drug & supplement interaction

Manganese + 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 Manganese 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

Manganese 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 Manganese 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.

Manganese safety at a glance

Manganese overall Use caution Safe in normal dietary amounts, but high-dose supplements can be harmful.
Pregnancy Use caution Amounts in foods and prenatal vitamins are appropriate, but avoid extra high-dose supplements unless advised.
Breastfeeding Likely Safe When used orally and appropriately. Manganese is safe when used in doses below the tolerable upper intake level (UL) of 11 mg daily during pregnancy or lactatio... 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 Manganese? 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. Manganese has documented interactions with 3 drug classes — the most serious being antipsychotic drugs (moderate), quinolone antibiotics (moderate) and tetracycline antibiotics (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

Manganese Does Interact With Other Medications

Manganese has 83 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 83 No known interaction 2,747 (incl. Levothyroxine)
Taking anything else?

Check Another of Your Medications Against Manganese

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

What to actually watch for

No Interaction Found — But Data Suggests Manganese 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. 2 of them are worth acting on rather than waiting out — marked below.

  • Bone thinning Worth acting on Additional detail

    Manganese

    “Chronic occupational exposure to manganese dust or fumes has been associated with lower bone quality in females, but not males, suggesting that prolonged manganese exposure might increase the risk of osteoporosis in females. A meta-analysis of 11 observational studies in adults also suggests that increased environmental exposure to airborne manganese sources is associated with lower motor function scores.”

    Manganese · Natural Medicines adverse-effect record, reported in bone loss.

    2 sources cited
    1. 102516. Li D, Ge X, Liu Z, et al. Association between long-term occupational manganese exposure and bone quality among retired workers. Environ Sci Pollut Res Int 2020;27(1):482-9. PubMed
    2. 108537. Ruiz-Azcona L, Fernández-Olmo I, Expósito A, et al. Impact of environmental airborne manganese exposure on cognitive and motor functions in adults: a systematic review and meta-analysis. Int J Environ Res Public Health 2021;18(8):4075. PubMed

    Levothyroxine

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

  • Muscle weakness Worth acting on Additional detail

    Manganese

    “Orally, there is concern that higher doses of manganese might increase the risk of neurotoxicity, including Parkinson-like extrapyramidal symptoms. One severe case of irreversible Parkinson disease possibly related to taking manganese 100 mg daily for 2-4 years has been reported.”

    Manganese · Natural Medicines adverse-effect record, reported in alcohol-related liver disease.

    6 sources cited
    1. 7135. Food and Nutrition Board, Institute of Medicine. Dietary Reference Intakes for Vitamin A, Vitamin K, Arsenic, Boron, Chromium, Copper, Iodine, Iron, Manganese, Molybdenum, Nickel, Silicon, Vanadium, and Zinc. Washington, DC: National Academy Press, 2002.
    2. 10665. Lee JW. Manganese intoxication. Arch Neurol 2000;57:597-9.. PubMed
    3. 10666. Powers KM, Smith-Weller T, Franklin GM, et al. Parkinson's disease risks associated with dietary iron, manganese, and other nutrient intakes. Neurology 2003;60:1761-6.. PubMed
    4. 96418. Schuh MJ. Possible Parkinson's disease induced by chronic manganese supplement ingestion. Consult Pharm. 2016;31(12):698-703. doi: 10.4140/TCP.n.2016.698. PubMed
    5. 112137. Uyar E, Gurkas E, Aksu AU, et al. Can therapeutic plasma exchange be life-saving in life-threatening manganese intoxication?. Transfus Apher Sci 2022;61(4):103417. PubMed
    6. 1992. Hauser RA, Zesiewicz TA, Martinez C, et al. Blood manganese correlates with brain magnetic resonance imaging changes in patients with liver disease. Can J Neurol Sci 1996;23:95-8. PubMed

    Levothyroxine

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

  • Tiredness Additional detail

    Manganese

    “Chronic occupational exposure to manganese dust or fumes can cause mood disturbance and dementia. A case report describes a man who presented with confusion, psychosis, dystonic limb movements, and cognitive impairment after chronic industrial manganese exposure.”

    Manganese · Natural Medicines adverse-effect record, reported in cognitive impairment.

    4 sources cited
    1. 1990. Barrington WW, Angle CR, Willcockson NK, et al. Autonomic function in manganese alloy workers. Environ Res 1998;78:50-8. PubMed
    2. 7135. Food and Nutrition Board, Institute of Medicine. Dietary Reference Intakes for Vitamin A, Vitamin K, Arsenic, Boron, Chromium, Copper, Iodine, Iron, Manganese, Molybdenum, Nickel, Silicon, Vanadium, and Zinc. Washington, DC: National Academy Press, 2002.
    3. 99415. Ho CSH, Ho RCM, Quek AML. Chronic manganese toxicity associated with voltage-gated potassium channel complex antibodies in a relapsing neuropsychiatric disorder. Int J Environ Res Public Health 2018;15(4). pii: E783. doi: 10.3390/ijerph15040783. PubMed
    4. 108536. Racette BA, Nelson G, Dlamini WW, et al. Depression and anxiety in a manganese-exposed community. Neurotoxicology 2021;85:222-33. PubMed

    Levothyroxine

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

Reported for Manganese but not commonly for Levothyroxine: low blood pressure, fainting, memory problems and liver problems.

Effects for Levothyroxine come from the ADVERSE REACTIONS section of its FDA label; effects for Manganese 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

Manganese in Pregnancy & Breastfeeding

Lactation Likely Safe

When used orally and appropriately. Manganese is safe when used in doses below the tolerable upper intake level (UL) of 11 mg daily during pregnancy or lactation in those aged 19 or older. However, those under 19 years of age should limit doses to less than 9 mg daily.

Lactation Possibly Unsafe

When used orally in excessive doses. Doses over the UL are associated with a greater risk of toxicity. Additionally, observational research shows that adults with higher blood manganese levels have greater odds of delivering low birth weight or small for gestational age (SGA) male, but not female, infants.

Lactation Likely Unsafe

When inhaled at moderate doses, long-term. Manganese salts can cross the placenta, and animal research suggests that large amounts of manganese may be teratogenic.

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 — Manganese Should Not Break It

At least one FDA label for a product containing Levothyroxine says to take it on an empty stomach. Most supplements — Manganese 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 Manganese 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 Manganese 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 Manganese 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 Manganese 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 Manganese as Part of a Dietary Supplement Product? Check It for Interactions

We hold 16,006 real supplement products containing Manganese, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Manganese. Even though Manganese 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 Manganese 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 Manganese
Top 5%

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

What is Manganese?

Manganese
  • Bone health support
  • Antioxidant and enzyme support
  • Filling dietary gaps
  • Metabolism support
  • Wound healing

Manganese is an essential trace mineral your body needs in small amounts for bone formation, metabolism, and antioxidant defense, and most people get enough from a normal diet. Supplements may help if you have a genuine deficiency, but too much can be harmful—especially to the nervous system—so do not take high doses without guidance from a pharmacist or doctor.

Mineral (dietary trace element) · Tablets, capsules, gummies, liquid drops, part of multivitamin/mineral and bone-health products

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

Manganese: dosing

There is no single "treatment dose" of manganese for most health goals. Health authorities have set recommended daily intakes for general nutrition and an upper limit that you should not exceed, because higher amounts increase the risk of harm.Most people meet their needs through food alone. If a supplement is recommended, the amount in a typical multivitamin or bone-health product is usually enough.

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

Read the full Manganese 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 & Manganese

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

0Major
83Moderate
0Minor
2,746No known interaction
83 Moderate 2,746 No interaction
Moderate

83 interactions

Showing 60 of 83 moderate interactions — see all 83 on the Manganese page.

No interaction 2,746 drugs checked — show the list

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

Showing the 60 most looked-up of 2,746 medications checked with no known interaction — see the full Manganese list.

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

Manganese References

The 21 references that drive our Manganese 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. Hansten PD, Horn JR. Hansten and Horn's Drug Interactions Analysis and Management. Vancouver, CAN:Appl Therapeut, 1999.
  2. Barrington WW, Angle CR, Willcockson NK, et al. Autonomic function in manganese alloy workers. Environ Res 1998;78:50-8. PubMed
  3. Hauser RA, Zesiewicz TA, Martinez C, et al. Blood manganese correlates with brain magnetic resonance imaging changes in patients with liver disease. Can J Neurol Sci 1996;23:95-8. PubMed
  4. Food and Nutrition Board, Institute of Medicine. Dietary Reference Intakes for Vitamin A, Vitamin K, Arsenic, Boron, Chromium, Copper, Iodine, Iron, Manganese, Molybdenum, Nickel, Silicon, Vanadium, and Zinc. Washington, DC: National Academy Press, 2002.
  5. Lee JW. Manganese intoxication. Arch Neurol 2000;57:597-9.. PubMed
  6. Powers KM, Smith-Weller T, Franklin GM, et al. Parkinson's disease risks associated with dietary iron, manganese, and other nutrient intakes. Neurology 2003;60:1761-6.. PubMed
  7. McMillan, D. E. A brief history of the neurobehavioral toxicity of manganese: some unanswered questions. Neurotoxicology 1999;20(2-3):499-507.
  8. Gerber, G. B., Leonard, A., and Hantson, P. Carcinogenicity, mutagenicity and teratogenicity of manganese compounds. Crit Rev Oncol Hematol. 2002;42(1):25-34. PubMed
  9. Jiang, Y. and Zheng, W. Cardiovascular toxicities upon manganese exposure. Cardiovasc.Toxicol 2005;5(4):345-354. PubMed
  10. Mehta, R. and Reilly, J. J. Manganese levels in a jaundiced long-term total parenteral nutrition patient: potentiation of haloperidol toxicity? Case report and literature review. JPEN J Parenter.Enteral Nutr 1990;14(4):428-430. PubMed
  11. Nemery, B. Metal toxicity and the respiratory tract. Eur Respir.J 1990;3(2):202-219. DOI
  12. Vanek VW, Borum P, Buchman A, et al. A.S.P.E.N. position paper: recommendations for changes in commercially available parenteral multivitamin and multi-trace element products. Nutr Clin Pract. 2012;27:440-491.doi: 10.1177/0884533612446706 PubMed
  13. Schuh MJ. Possible Parkinson's disease induced by chronic manganese supplement ingestion. Consult Pharm. 2016;31(12):698-703. doi: 10.4140/TCP.n.2016.698. PubMed
  14. Baker B, Ali A, Isenring L. Recommendations for manganese supplementation to adult patients receiving long-term home parenteral nutrition: an analysis of the supporting evidence. Nutr Clin Pract 2016;31(2):180-5. doi: 10.1177/0884533615591600. PubMed
  15. Ho CSH, Ho RCM, Quek AML. Chronic manganese toxicity associated with voltage-gated potassium channel complex antibodies in a relapsing neuropsychiatric disorder. Int J Environ Res Public Health 2018;15(4). pii: E783. doi: 10.3390/ijerph15040783. 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 Manganese and Levothyroxine Together: Common Questions

Is it safe to take Manganese with Levothyroxine?
We do not list a known interaction between Manganese 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 Manganese and Levothyroxine have any of the same side effects?
Yes — our sources link each of them separately to 3 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 Manganese 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 Manganese 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 Manganese and Levothyroxine combination checked?
Interactions in our licensed database are recorded against drug classes. Levothyroxine is filed under 3 classifications, and Manganese has documented interactions with 3 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 Manganese interact with any other medications?
Yes. Manganese has 83 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 — Manganese 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

Manganese 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 21 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Levothyroxine and Manganese?

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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.