Drug & supplement interaction

Trypsin + 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 Trypsin 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. Additionally, although there is no interaction, 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

Trypsin 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 Trypsin 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 Trypsin 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.

Trypsin safety at a glance

Trypsin overall Use caution Generally tolerated in studied products, but quality and evidence vary, so use under guidance.
Pregnancy Avoid Safety is not established, so it is best avoided during pregnancy.
Breastfeeding Avoid There is not enough information to confirm safety while breastfeeding.

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

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

No Interaction Found — But Data Suggests Trypsin and Letrozole May Share a Side Effect

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.

  • Nausea Additional detail

    Trypsin

    “Topically, trypsin can cause localized pain and transient burning. Orally, trypsin taken in combination with other enzymes can cause mild-to-moderate gastrointestinal symptom such as nausea, heartburn, and stomach pain. It is not known if trypsin or other enzymes causes these adverse effects.”

    Trypsin · Natural Medicines adverse-effect record, reported in dyspepsia.

    3 sources cited
    1. 506. Burnham TH, ed. Drug Facts and Comparisons, Updated Monthly. Facts and Comparisons, St. Louis, MO.
    2. 37193. Klein, G., Kullich, W., Schnitker, J., and Schwann, H. Efficacy and tolerance of an oral enzyme combination in painful osteoarthritis of the hip. A double-blind, randomised study comparing oral enzymes with non-steroidal anti-inflammatory drugs. Clin Exp
    3. 92235. Bolten WW, Glade MJ, Raum S, Ritz BW. The safety and efficacy of an enzyme combination in managing knee osteoarthritis pain in adults: a randomized, double-blind, placebo-controlled trial. Arthritis 2015;2015:251521. PubMed

    “Orally, trypsin taken in combination with other enzymes can cause mild-to-moderate gastrointestinal symptom such as nausea, heartburn, and stomach pain. It is not known if trypsin or other enzymes causes these adverse effects.”

    Trypsin · Natural Medicines adverse-effect record, reported in dyspepsia.

    2 sources cited
    1. 37193. Klein, G., Kullich, W., Schnitker, J., and Schwann, H. Efficacy and tolerance of an oral enzyme combination in painful osteoarthritis of the hip. A double-blind, randomised study comparing oral enzymes with non-steroidal anti-inflammatory drugs. Clin Exp
    2. 92235. Bolten WW, Glade MJ, Raum S, Ritz BW. The safety and efficacy of an enzyme combination in managing knee osteoarthritis pain in adults: a randomized, double-blind, placebo-controlled trial. Arthritis 2015;2015:251521. PubMed

    Letrozole

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

Reported for Trypsin but not commonly for Letrozole: stomach pain and heartburn.

Effects for Letrozole come from the ADVERSE REACTIONS section of its FDA label; effects for Trypsin 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.

From our Q&A

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

We hold 353 real supplement products containing Trypsin, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Trypsin. Even though Trypsin 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 Trypsin 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 Trypsin
Top half

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

29 days ago today
Medication Letrozole
Top 5%

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

What is Trypsin?

  • Swelling and inflammation after injury or surgery
  • Wound and ulcer cleaning (topical)
  • Aiding digestion (in combination enzyme products)
  • Muscle and joint pain
  • Recovery after sports injuries

Trypsin is a protein-digesting enzyme usually taken from the pancreas of animals and used either by mouth (often combined with other enzymes like chymotrypsin and bromelain) for swelling and recovery, or applied to the skin to help clean wounds. Evidence for oral 'systemic enzyme' use is mixed and mostly preliminary, and topical uses are better established for wound care. Talk to a pharmacist or doctor before using it, especially if you are pregnant, breastfeeding, or have allergies.

Enzyme derived from the pancreas of animals (often pork or cattle); also produced from microbial sources · Oral enteric-coated tablets, combination enzyme products, and topical ointments or wound-care preparations

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

Trypsin: dosing

There is no single established dose for trypsin. Do not assume more is better, and avoid using it in place of a treatment your doctor has prescribed.

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

Read the full Trypsin 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 & Trypsin

Browse every other medication we’ve checked against Trypsin — 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 Trypsin 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 Trypsin list.

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

Trypsin References

The 17 references that drive our Trypsin 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. Burnham TH, ed. Drug Facts and Comparisons, Updated Monthly. Facts and Comparisons, St. Louis, MO.
  2. Latha B, Ramakrishnan M, Jayaraman V, Babu M. The efficacy of trypsin: chymotrypsin preparation in the reduction of oxidative damage during burn injury. Burns 1998;24:532-8. PubMed
  3. Latha B, Ramakrishnan M, Jayaraman V, Babu M. Serum enzymatic changes modulated using trypsin: chymotrypsin preparation during burn wounds in humans. Burns 1997;23:560-4. PubMed
  4. Klein, G., Kullich, W., Schnitker, J., and Schwann, H. Efficacy and tolerance of an oral enzyme combination in painful osteoarthritis of the hip. A double-blind, randomised study comparing oral enzymes with non-steroidal anti-inflammatory drugs. Clin Exp
  5. Dale, P. S., Tamhankar, C. P., George, D., and Daftary, G. V. Co-medication with hydrolytic enzymes in radiation therapy of uterine cervix: evidence of the reduction of acute side effects. Cancer Chemother.Pharmacol 2001;47 Suppl:S29-S34. PubMed
  6. Martin, T., Uhder, K., Kurek, R., Roeddiger, S., Schneider, L., Vogt, H. G., Heyd, R., and Zamboglou, N. Does prophylactic treatment with proteolytic enzymes reduce acute toxicity of adjuvant pelvic irradiation? Results of a double-blind randomized trial PubMed
  7. Miller, P. C., Bailey, S. P., Barnes, M. E., Derr, S. J., and Hall, E. E. The effects of protease supplementation on skeletal muscle function and DOMS following downhill running. J Sports Sci 2004;22(4):365-372. PubMed
  8. Bolten WW, Glade MJ, Raum S, Ritz BW. The safety and efficacy of an enzyme combination in managing knee osteoarthritis pain in adults: a randomized, double-blind, placebo-controlled trial. Arthritis 2015;2015:251521. PubMed
  9. US Department of Justice. U.S. Files Complaint Against Texas-Based Healthpoint Ltd. Under the False Claims Act. https://www.justice.gov/opa/pr/us-files-complaint-against-texas-based-healthpoint-ltd-under-false-claims-act. (Accessed June 19, 2019).
  10. Grabs V, Kersten A, Haller B, et al. Rutoside and hydrolytic enzymes do not attenuate marathon-induced inflammation. Med Sci Sports Exerc. 2017;49(3):387-395. PubMed
  11. Baumhackl U, Kappos L, Radue EW, et al. A randomized, double-blind, placebo-controlled study of oral hydrolytic enzymes in relapsing multiple sclerosis. Mult Scler. 2005;11(2):166-8. PubMed
  12. Gujral MS, Patnaik PM, Kaul R, et al. Efficacy of hydrolytic enzymes in preventing radiation therapy-induced side effects in patients with head and neck cancers. Cancer Chemother Pharmacol. 2001;47 Suppl:S23-8. PubMed
  13. Kempf K, Manzo G, Hanifi-Moghaddam P, et al. Effect of combined oral proteases and flavonoid treatment in subjects at risk of Type 1 diabetes. Diabet Med. 2009;26(12):1309-10. PubMed
  14. Kerkhoffs GM, Struijs PA, de Wit C, Rahlfs VW, Zwipp H, van Dijk CN. A double blind, randomised, parallel group study on the efficacy and safety of treating acute lateral ankle sprain with oral hydrolytic enzymes. Br J Sports Med. 2004;38(4):431-5. PubMed
  15. Popiela T, Kulig J, Klek S, Wachol D, Bock PR, Hanisch J. Double-blind pilot-study on the efficacy of enzyme therapy in advanced colorectal cancer. Przegl Lek. 2000;57 Suppl 5:142.

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 Trypsin and Letrozole Together: Common Questions

Is it safe to take Trypsin with Letrozole?
We do not list a known interaction between Trypsin 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.
Do Trypsin and Letrozole have any of the same side effects?
Yes — our sources link each of them separately to one 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.
Does Letrozole interact with any supplements?
Yes. Letrozole has documented interactions with 142 supplements in our database — Trypsin 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

Trypsin 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 17 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Letrozole and Trypsin?

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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.