Drug & supplement interaction

Idebenone + 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 Idebenone 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

Idebenone 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 Idebenone 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 Idebenone 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.

Idebenone safety at a glance

Idebenone overall Use caution Generally tolerated in studies but long-term supplement safety is not well established.
Pregnancy Avoid There is not enough safety information, so avoid use during pregnancy.
Breastfeeding Avoid There is not enough safety information, so avoid use while breastfeeding.

Safety guidance is general; always confirm with your pharmacist or doctor for your situation.

Still wondering about combining Levothyroxine and Idebenone? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
What to actually watch for

No Interaction Found — But Data Suggests Idebenone 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. One of them is worth acting on rather than waiting out — marked below.

  • An allergic reaction Worth acting on Additional detail

    Idebenone

    “There is a case report of allergic contact dermatitis related to topical use of a cream containing idebenone. The 38-year old woman applied a facial cream (Prevage MD, Elizabeth Arden, Inc.) with reactions appearing with the second dose. Symptoms included a red, itchy, burning, swollen face. She was treated with topical hydrocortisone. She reacted to idebenone with patch testing.”

    Idebenone · Natural Medicines adverse-effect record, reported in dermatitis.

    1 source cited
    1. 96035. Mc Aleer MA, Collins P. Allergic contact dermatitis to hydroxydecyl ubiquinone (idebenone) following application of anti-ageing cosmetic cream. Contact Dermatitis. 2008;59(3):178-9. PubMed

    Levothyroxine

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

  • Increased appetite Additional detail

    Idebenone

    “Orally, adverse effects related to idebenone have included nausea and vomiting, abdominal pain, elevated alkaline phosphatase, and loose stools. Increased appetite leading to weight gain has also been reported.”

    Idebenone · Natural Medicines adverse-effect record, reported in nausea and vomiting.

    5 sources cited
    1. 96028. Buyse GM, Voit T, Schara U, DELOS Study Group. Efficacy of idebenone on respiratory function in patients with Duchenne muscular dystrophy not using glucocorticoids (DELOS): a double-blind randomised placebo-controlled phase 3 trial. Lancet. 2015;385(9979) PubMed
    2. 96034. Lynch DR, Perlman SL, Meier T. A phase 3, double-blind, placebo-controlled trial of idebenone in friedreich ataxia. Arch Neurol. 2010;67(8):941-7. PubMed
    3. 105705. Catarino CB, von Livonius B, Priglinger C, et al. Real-world clinical experience with idebenone in the treatment of leber hereditary optic neuropathy. J Neuroophthalmol. 2020 Dec;40(4):558-565.
    4. 105708. Zhao X, Zhang Y, Lu L, Yang H. Therapeutic effects of idebenone on leber hereditary optic neuropathy. Curr Eye Res. 2020 Oct;45(10):1315-1323. PubMed
    5. 11413. Hausse AO, Aggoun Y, Bonnet D, et al. Idebenone and reduced cardiac hypertrophy in Friedreich's ataxia. Heart 2002;87:346-9. PubMed

    Levothyroxine

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

  • A fast or pounding heartbeat Additional detail

    Idebenone

    “In a clinical trial, tachycardia was reported by a single person taking idebenone orally. Treatment was not required.”

    Idebenone · Natural Medicines adverse-effect record, reported in irregular heartbeat.

    1 source cited
    1. 11410. Mariotti C, Solari A, Torta D, et al. Idebenone treatment in Friedreich patients: one-year-long randomized placebo-controlled trial. Neurology 2003;60:1676-9. PubMed

    Levothyroxine

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

  • Stomach pain / Diarrhea / Vomiting / Nausea Additional detail

    Idebenone

    “Orally, idebenone seems to be well-tolerated. In clinical studies, there have been no reports of serious adverse effects occurring more frequently than with placebo. Some people who take idebenone have experienced nausea and vomiting, abdominal pain, elevated alkaline phosphatase, and loose stools; however, these side effects are not common.”

    Idebenone · Natural Medicines adverse-effect record, reported in dermatitis.

    6 sources cited
    1. 11410. Mariotti C, Solari A, Torta D, et al. Idebenone treatment in Friedreich patients: one-year-long randomized placebo-controlled trial. Neurology 2003;60:1676-9. PubMed
    2. 11413. Hausse AO, Aggoun Y, Bonnet D, et al. Idebenone and reduced cardiac hypertrophy in Friedreich's ataxia. Heart 2002;87:346-9. PubMed
    3. 11421. Weyer G, Babej-Dolle RM, Hadler D, et al. A controlled study of 2 doses of idebenone in the treatment of Alzheimer's disease. Neuropsychobiology 1997;36:73-82. . PubMed
    4. 11424. Pisano P, Durand A, Autret E, et al. Plasma concentrations and pharmacokinetics of idebenone and its metabolites following single and repeated doses in young patients with mitochondrial encephalomyopathy. Eur J Clin Pharmacol 1996;51:167-9. PubMed
    5. 11427. Gutzmann H, Hadler D. Sustained efficacy and safety of idebenone in the treatment of Alzheimer's disease: update on a 2-year double-blind multicentre study. J Neural Transm 1998;54:301-10. PubMed
    6. 15703. Di Prospero NA, Sumner CJ, Penzak SR, et al. Safety, tolerability, and pharmacokinetics of high-dose idebenone in patients with Friedreich ataxia. Arch Neurol 2007;64:803-8. PubMed

    Levothyroxine

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

  • A skin rash Additional detail

    Idebenone

    Recorded for Idebenone in the same Natural Medicines adverse-effect record shown under Stomach pain / Diarrhea / Vomiting / Nausea above.

    Levothyroxine

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

Reported for Idebenone but not commonly for Levothyroxine: weight gain.

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

How to take them

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

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

Overlapping uses

What Levothyroxine Is Prescribed For, and What Idebenone Has Been Studied For

These two come up together because they touch the same health topic — not because they do the same job. Levothyroxine is a prescription medicine with approved uses on its FDA label. Idebenone is a supplement: what follows is what researchers have looked at it for, and how strong that evidence is.

Levothyroxine is prescribed for: 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.

Idebenone has been studied for:

  • Depression studied, not established Idebenone has been studied for this. Natural Medicines rates the evidence: Insufficient Reliable Evidence To Rate Read what the research shows

    Idebenone for depression

    Preliminary clinical research in adults aged 55-75 years with post-stroke depression suggests that adding idebenone 30 mg three times daily to paroxetine treatment for 12 weeks increases the effectiveness (cured or improved) rate, as measured by the Hamilton Rating Scale for Depression, from 62% with paroxetine alone to 82% with the combination.

    1 source cited
    1. 112059. Yuan LL, Chen TY, Huang ZQ. Effects of paroxetine hydrochloride combined with idebenone on inflammatory factors and antioxidant molecules in treatment of depression after ischemic stroke. Pak J Med Sci 2023;39(1):17-22. PubMed

Effectiveness ratings and the research summaries above are the verbatim record from the Natural Medicines database, which grades evidence from “Effective” down to “Insufficient Reliable Evidence To Rate”. A rating below the top of that scale means researchers have looked at it — not that it works, and never that it can stand in for a prescribed medicine. Do not stop or replace Levothyroxine on your own; if you are taking Idebenone for the same health topic, tell your prescriber, especially if the medicine is being adjusted to a target.

From our Q&A

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

We hold 17 real supplement products containing Idebenone, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Idebenone. Even though Idebenone 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 Idebenone 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 Idebenone
Top half

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

What is Idebenone?

  • Antioxidant support
  • Brain and memory health
  • Mitochondrial disorders
  • Anti-aging skin care
  • General energy support

Idebenone is a synthetic, lab-made antioxidant related to coenzyme Q10. It has been studied mostly as a prescription drug for certain rare mitochondrial and neurological conditions, and is also used in some skin-care products, but evidence for over-the-counter supplement use is limited. Talk with your pharmacist or doctor before using it.

Synthetic compound (a lab-made analog of coenzyme Q10) · Capsules, tablets, topical creams and serums

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

Idebenone: dosing

There is no standard supplement dose of idebenone that experts agree on. Doses used in medical studies for specific diseases were set by researchers and differ from what is found in over-the-counter products.If you choose to use an idebenone supplement, follow the directions on the product label and do not exceed the recommended amount.

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

Read the full Idebenone 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 & Idebenone

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

0Major
0Moderate
0Minor
2,829No known interaction
No interaction 2,829 drugs checked — show the list
Evidence & sources

Idebenone References

The 25 references that drive our Idebenone 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. Mariotti C, Solari A, Torta D, et al. Idebenone treatment in Friedreich patients: one-year-long randomized placebo-controlled trial. Neurology 2003;60:1676-9. PubMed
  2. Filla A, Moss AJ. Idebenone for treatment of Friedreich's ataxia? Neurology 2003;60:1569-70. PubMed
  3. Hausse AO, Aggoun Y, Bonnet D, et al. Idebenone and reduced cardiac hypertrophy in Friedreich's ataxia. Heart 2002;87:346-9. PubMed
  4. Schols L, Vorgerd M, Schillings M, et al. Idebenone in patients with Friedreich ataxia. Neurosci Lett 2001;306:169-72. PubMed
  5. Lerman-Sagie T, Rustin P, Lev D, et al. Dramatic improvement in mitochondrial cardiomyopathy following treatment with idebenone. J Inherit Metab Dis 2001;24:28-34. PubMed
  6. Rustin P, von Kleist-Retzow JC, Chantrel-Groussard K, et al. Effect of idebenone on cardiomyopathy in Friedreich's ataxia: a preliminary study. Lancet 1999;354:477-9. PubMed
  7. Weyer G, Babej-Dolle RM, Hadler D, et al. A controlled study of 2 doses of idebenone in the treatment of Alzheimer's disease. Neuropsychobiology 1997;36:73-82. . PubMed
  8. Ikejiri Y, Mori E, Ishii K, et al. Idebenone improves cerebral mitochondrial oxidative metabolism in a patient with MELAS. Neurology 1996;47:583-5. PubMed
  9. Pisano P, Durand A, Autret E, et al. Plasma concentrations and pharmacokinetics of idebenone and its metabolites following single and repeated doses in young patients with mitochondrial encephalomyopathy. Eur J Clin Pharmacol 1996;51:167-9. PubMed
  10. Ihara Y, Namba R, Kuroda S, et al. Mitochondrial encephalomyopathy (MELAS): pathological study and successful therapy with coenzyme Q10 and idebenone. J Neurol Sci 1989;90:263-71. PubMed
  11. Gutzmann H, Hadler D. Sustained efficacy and safety of idebenone in the treatment of Alzheimer's disease: update on a 2-year double-blind multicentre study. J Neural Transm 1998;54:301-10. PubMed
  12. Di Prospero NA, Sumner CJ, Penzak SR, et al. Safety, tolerability, and pharmacokinetics of high-dose idebenone in patients with Friedreich ataxia. Arch Neurol 2007;64:803-8. PubMed
  13. Buyse GM, Voit T, Schara U, DELOS Study Group. Efficacy of idebenone on respiratory function in patients with Duchenne muscular dystrophy not using glucocorticoids (DELOS): a double-blind randomised placebo-controlled phase 3 trial. Lancet. 2015;385(9979) PubMed
  14. Corben LA, Lynch D, Pandolfo M, Schulz JB, Delatycki MB; Clinical Management Guidelines Writing Group. Consensus clinical management guidelines for Friedreich ataxia. Orphanet J Rare Dis. 2014;9:184. DOI
  15. Di Prospero NA, Baker A, Jeffries N, Fischbeck KH. Neurological effects of high-dose idebenone in patients with Friedreich's ataxia: a randomised, placebo-controlled trial. Lancet Neurol. 2007;6(10):878-86. 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 Idebenone and Levothyroxine Together: Common Questions

Is it safe to take Idebenone with Levothyroxine?
We do not list a known interaction between Idebenone 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 Idebenone and Levothyroxine have any of the same side effects?
Yes — our sources link each of them separately to 8 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 Idebenone 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 Idebenone 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.
Are Idebenone and Levothyroxine used for the same thing?
They overlap in purpose, which usually means the real question is whether you need both rather than whether they are safe together. This page lists the shared uses and how strong the evidence is for Idebenone in each. That is a conversation for your prescriber, especially if Levothyroxine is being adjusted to a target.
Does Levothyroxine interact with any supplements?
Yes. Levothyroxine has documented interactions with 50 supplements in our database — Idebenone 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 Idebenone?

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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.