Drug & supplement interaction

Glutathione + Letrozole

Letrozole brand name: Femara.

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 Glutathione and Letrozole 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.

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Interaction report

Glutathione and Letrozole

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 Letrozole 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 Letrozole, 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 Letrozole and Glutathione? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
What to actually watch for

What Glutathione Itself Has Been Linked To

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

  • Wheezing / Shortness of breath Worth acting on Additional detail

    “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
  • Cough Additional detail

    Recorded for Glutathione in the same Natural Medicines adverse-effect record shown under Wheezing / Shortness of breath above.

Everything above comes from the Natural Medicines adverse-effect record for Glutathione — expand a row for the licensed statement it rests on. We read the ADVERSE REACTIONS section of Letrozole’s FDA label too, and the two lists don’t meaningfully overlap — which is why no Letrozole column appears here.

From our Q&A

Questions About Glutathione or Letrozole

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 Letrozole, 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 Letrozole

This page covers Glutathione only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Letrozole page lists 142 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Grapefruit (major), St. John's Wort (major), 7-methoxyflavone (moderate) and Acacia Rigidula (moderate).

By severity: 3 major · 99 moderate · 40 minor.

From our pharmacist’s overview on the Letrozole page

“Letrozole (Femara) is prescribed to keep hormone-driven breast cancer from returning, so a supplement that shifts its blood level can quietly undercut treatment. Give this list of 142 ingredients genuine respect, and learn the three major entries first.”

Reviewed by 2 · Jul 18, 2026

Open the Letrozole 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 Letrozole, 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 Letrozole 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%

#212 of 1,452 supplements looked up here in the last 7 days

29 days ago today
Medication Letrozole
Top 5%

#50 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 September 13, 2026. The Glutathione and Letrozole 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 Letrozole

What Is Letrozole Used For?

Brand name: Femara

Letrozole (brand name Femara) is used to treat breast cancer in postmenopausal women whose tumors are driven by estrogen. It is used in three settings: as adjuvant (after-surgery) treatment for hormone receptor positive early breast cancer; as extended adjuvant treatment for women who have already completed about five years of tamoxifen therapy; and as first- or second-line treatment for locally advanced or metastatic (spread) breast cancer.

Femara is specifically indicated for first-line treatment of hormone receptor positive or receptor-unknown locally advanced or metastatic breast cancer, and for advanced breast cancer in women whose disease has progressed after antiestrogen therapy.

See full Letrozole 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 Letrozole, 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 Letrozole Together: Common Questions

Is it safe to take Glutathione with Letrozole?
We do not list a known interaction between Glutathione and Letrozole. 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.
Does Letrozole interact with any supplements?
Yes. Letrozole has documented interactions with 142 supplements in our database — Glutathione is not one of them. The Letrozole 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 Letrozole drug information The full plain-English guide to this medication Letrozole supplement interactions Every supplement checked against Letrozole, 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 Letrozole and Glutathione?

Our pharmacists answer your medication & supplement questions — free.

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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.