Drug & supplement interaction

Glutathione + Levothyroxine

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

No Known Interaction
Medically reviewed by · Updated July 2026 · Pair last verified Oct 4, 2026
The bottom line No known interaction

We found no known interaction between Glutathione 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

Glutathione 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 Glutathione 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 Glutathione 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.

Glutathione safety at a glance

Glutathione overall Use caution Oral forms appear generally well tolerated short-term, but long-term safety and the safety of IV and inhaled forms are less clear.
Pregnancy Avoid There is not enough reliable safety information, so it is best avoided during pregnancy unless your doctor advises otherwise.
Breastfeeding Avoid There is not enough reliable safety information during breastfeeding, so caution and avoidance are advised.

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

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

No Interaction Found — But Data Suggests Glutathione 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.

  • Wheezing / Shortness of breath Worth acting on Additional detail

    Glutathione

    “Inhaled (nebulized) glutathione can cause airway narrowing and bronchoconstriction resulting in shortness of breath and cough in patients with asthma.”

    Glutathione · Natural Medicines adverse-effect record, reported in asthma.

    1 source cited
    1. 5372. Marrades RM, Roca J, Barbera JA, et al. Nebulized glutathione induces bronchoconstriction in patients with mild asthma. Am J Respir Crit Care Med 1997;156(2 Pt 1):425-30. PubMed

    Levothyroxine

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

Reported for Glutathione but not commonly for Levothyroxine: cough.

Effects for Levothyroxine come from the ADVERSE REACTIONS section of its FDA label; effects for Glutathione 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 — Glutathione Should Not Break It

At least one FDA label for a product containing Levothyroxine says to take it on an empty stomach. Most supplements — Glutathione 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 Glutathione 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 Glutathione 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. Glutathione 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 thyroid hormone when your body does not make enough. The oral products (tablets, capsules and oral solution) treat hypothyroidism, which can be present from birth or develop later. They are also used alongside surgery and radioiodine therapy for thyrotropin-dependent well-differentiated thyroid cancer. Levothyroxine Sodium injection (given intravenously) is used only for myxedema coma, a life-threatening emergency from severe hypothyroidism.

Read the rest of what Levothyroxine is prescribed for

Age ranges differ by product. For example, Tirosint capsules are labeled for adults and children 6 years and older.

Glutathione has been studied for:

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

    Glutathione for depression

    Although there is interest in using oral glutathione for depression, there is insufficient reliable information about the clinical effects of glutathione for this condition.

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 Glutathione for the same health topic, tell your prescriber, especially if the medicine is being adjusted to a target.

From our Q&A

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

We hold 1,212 real supplement products containing Glutathione, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Glutathione. Even though Glutathione 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 Glutathione 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 Glutathione
Top 25%

#226 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 Glutathione reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified October 4, 2026. The Glutathione 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 Glutathione

What is Glutathione?

Glutathione
  • Antioxidant support
  • Skin lightening or brightening
  • Detoxification support
  • Immune support
  • Liver health
  • Anti-aging

Glutathione is a powerful antioxidant your body makes naturally, and many people take it as a supplement hoping for skin, detox, or anti-aging benefits. However, strong human evidence is limited for most uses, and oral glutathione is poorly absorbed. Talk to your pharmacist or doctor before starting, especially if you are considering IV or inhaled forms.

Not applicable (a compound made of three amino acids: cysteine, glutamic acid, and glycine) · Oral capsules and tablets, liposomal liquid, lozenges, intravenous (IV) injections, nebulized (inhaled) forms, topical creams

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

Glutathione: dosing

There is no official, standardized dose of glutathione for any health condition. Supplement products vary widely in their form and amount.The best advice is to follow the directions on the product label and not exceed them. Because oral glutathione is poorly absorbed, taking more does not necessarily mean more benefit.IV and inhaled forms should only be used under the care of a healthcare provider.

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

Read the full Glutathione 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 thyroid hormone when your body does not make enough. The oral products (tablets, capsules and oral solution) treat hypothyroidism, which can be present from birth or develop later. They are also used alongside surgery and radioiodine therapy for thyrotropin-dependent well-differentiated thyroid cancer.

Levothyroxine Sodium injection (given intravenously) is used only for myxedema coma, a life-threatening emergency from severe hypothyroidism. Age ranges differ by product. For example, Tirosint capsules are labeled for adults and children 6 years and older.

Most-Reported Side Effects for Levothyroxine

From FAERS, the FDA’s public side-effect reporting system (0 reports, all brands). Reports are voluntary and are not proof the drug caused the effect.

Fatigue 26,588 reports
Nausea 22,608 reports
Headache 19,408 reports
Diarrhea 18,758 reports
Dyspnea 16,725 reports
See full Levothyroxine drug information
Keep checking

Other Drugs & Glutathione

Browse every other medication we’ve checked against Glutathione — 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
2,829 No interaction
No interaction 2,829 drugs checked — show the list

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

Showing the 60 most looked-up of 2,829 medications checked with no known interaction — see the full Glutathione list.

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

Glutathione References

The 1 references that drive our Glutathione 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. Marrades RM, Roca J, Barbera JA, et al. Nebulized glutathione induces bronchoconstriction in patients with mild asthma. Am J Respir Crit Care Med 1997;156(2 Pt 1):425-30. 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 Glutathione and Levothyroxine Together: Common Questions

Is it safe to take Glutathione with Levothyroxine?
We do not list a known interaction between Glutathione 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 Glutathione 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 Glutathione 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 Glutathione 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 Glutathione 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 Glutathione 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 — Glutathione 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

Glutathione 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 1 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Levothyroxine and Glutathione?

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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.