Drug & supplement interaction

Yerba Mate + Exemestane

Exemestane brand name: Aromasin.

Minor Interaction
Medically reviewed by · Updated September 2026
The bottom line Minor

Yerba Mate has a minor interaction with Exemestane. Theoretically, yerba mate might increase the levels and clinical effects of CYP3A4 substrates.

Read the full interaction report
SeverityMinor
LikelihoodPossible
EvidenceD
What do Severity, Likelihood & Evidence mean?
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Interaction report

Yerba Mate and Exemestane

Here is the interaction we found between these two, with the evidence behind it.

Minor

CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES

Why this applies to Exemestane

Exemestane falls under CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES — the group Yerba Mate interacts with.

Theoretically, yerba mate might increase the levels and clinical effects of CYP3A4 substrates.
In vitro research shows that yerba mate extract inhibits CYP3A4 enzymes. Theoretically, taking yerba mate may increase levels and adverse effects of CYP3A4 substrates.
Severity Minor Likelihood Possible Evidence D

Interaction has been documented in animal or in lab research, or the interaction has been documented in humans but is limited to case reports or conflicting clinical research exists.

Dr. Brian Staiger, PharmD, BCPS
Dr. Brian Staiger explains PharmD, Clinical Pharmacist

Here's the gist: your body uses an enzyme called CYP3A4 to help break down exemestane (Aromasin). In lab dish studies, yerba mate appears to slow that same enzyme down a bit. In theory, that could let a little more exemestane linger in your system, which might bump up the usual side effects like hot flashes, joint or muscle aches, tiredness, or trouble sleeping.

I want to keep this in perspective, though. This is rated a minor interaction, and the only evidence so far comes from test-tube work, not real people. A cup or two of mate likely isn't a big deal, but concentrated supplement-strength extracts are less predictable. Since exemestane is an important cancer medication, just give your oncologist or pharmacist a heads-up before adding regular mate or extracts.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Feltrin C, Farias IV, Sandjo LP, Reginatto FH, Simões CMO. Effects of Standardized Medicinal Plant Extracts on Drug Metabolism Mediated by CYP3A4 and CYP2D6 Enzymes. Chem Res Toxicol 2020;33(9):2408-2419. PubMed

What These Ratings Mean

Every interaction above is graded three ways — here’s the key to each label.

Severity how clinically significant the interaction is
Major

Clinically significant. Avoid the combination, or use only under close professional supervision.

Moderate

Usually worth avoiding or managing — may need monitoring, a dose change, or timing apart.

Minor

Generally not serious. Be aware of it and mention it to your pharmacist.

Likelihood how strong the evidence is that the interaction actually happens in people
  • LikelyWell-controlled human studies have demonstrated the likely existence of this interaction.
  • ProbableInteraction has not been documented in well-controlled studies, however, the interaction has been demonstrated in some small human studies or in controlled animal studies in conjunction with multiple case reports.
  • PossibleInteraction has been documented in animal or in lab research, or the interaction has been documented in humans but is limited to case reports or conflicting clinical research exists.
  • UnlikelyInteraction has been demonstrated in animal or in lab research but has been shown not to occur in humans.
Evidence the quality of the studies behind the rating (graded A–D)
  • AHigh-quality meta-analysis (quantitative systematic review).
  • BCase-control study.
  • CConsensus.
  • DAnecdotal evidence.

These ratings are for information only. Never start, stop, or otherwise change your therapy before speaking with your provider.

Keep it in perspective

Yerba Mate Also Interacts With Other Medications

Yerba Mate has 8 major, 505 moderate, 572 minor known drug interactions in our database — the Exemestane one above is one of them. If you take anything else, check it against the full list below.

Major 8 Moderate 505 Minor 572 No known interaction 1,745 (incl. Exemestane)
Taking anything else?

Check Another of Your Medications Against Yerba Mate

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

Everything else you take

See Every Supplement That Interacts With Exemestane

This page covers Yerba Mate only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Exemestane page lists 141 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 · 98 moderate · 40 minor.

From our pharmacist’s overview on the Exemestane page

“Exemestane (Aromasin) is an aromatase inhibitor for hormone-sensitive breast cancer, and because its job is keeping estrogen suppressed, anything that shifts its blood level puts the treatment itself at risk. This list deserves real care.”

Reviewed by 2 · Jul 18, 2026

Open the Exemestane interaction page

One more smart check

Taking Yerba Mate as Part of a Dietary Supplement Product? Check It for Interactions

We hold 68 real supplement products containing Yerba Mate, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Yerba Mate. Your product may carry other ingredients that interact with Exemestane too, on top of Yerba Mate — and those would not show on this page. Find your product and we’ll check every ingredient on its label:

How much people look this up

Where Yerba Mate and Exemestane 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 Yerba Mate
Steady interest

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

29 days ago today
Medication Exemestane
Steady interest

#1,824 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.

Supplement

About Yerba Mate

What is Yerba Mate?

Yerba Mate
  • Energy and alertness
  • Weight loss
  • Mental focus
  • Digestive support
  • Antioxidant support

Yerba mate is a caffeine-containing herbal beverage from South America that is widely enjoyed for its stimulating, coffee-like effects. While it is rich in antioxidants and is being studied for weight, blood sugar, and cholesterol, strong human evidence for most health claims is limited. Drinking very hot mate over many years has been linked to higher risk of certain cancers, so enjoy it warm and in moderation.

Read the full Yerba Mate monograph & all interactions
Medication

About Exemestane

What Is Exemestane Used For?

Brand name: Aromasin

Exemestane (brand name Aromasin) is used in postmenopausal women with estrogen-receptor positive early breast cancer who have already taken tamoxifen for two to three years — it is then used to complete a total of five years of hormonal therapy. It is also used to treat advanced breast cancer in postmenopausal women whose cancer continued to grow during or after tamoxifen therapy.

These uses apply to Aromasin and the generic exemestane tablets. This medication is not approved for breast cancer in premenopausal women.

See full Exemestane drug information
Keep checking

Other Drugs & Yerba Mate

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

8Major
505Moderate
572Minor
1,744No known interaction
8 Major 505 Moderate 572 Minor 1,744 No interaction
Major

8 interactions

Moderate

505 interactions

Showing 60 of 505 moderate interactions — see all 505 on the Yerba Mate page.

Minor

572 interactions

Showing 60 of 572 minor interactions — see all 572 on the Yerba Mate page.

No interaction 1,744 drugs checked — show the list

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

Showing the 60 most looked-up of 1,744 medications checked with no known interaction — see the full Yerba Mate list.

See the full Yerba Mate interactions page
See every supplement checked against Exemestane, ranked by severity
Sources

Sources & How We Checked

Interaction details are evidence-graded and sourced from the Natural Medicines database. The medication overview comes from MedlinePlus.

Content is written and reviewed by licensed HelloPharmacist pharmacists. See our data sources and editorial standards for how this information is built and checked.

Parts of this content are provided by the Therapeutic Research Center, LLC.

DISCLAIMER: Currently this does not check for drug-drug interactions. This is not an all-inclusive comprehensive list of potential interactions and is for informational purposes only. Not all interactions are known or well-reported in the scientific literature, and new interactions are continually being reported. Input is needed from a qualified healthcare provider including a pharmacist before starting any therapy. Application of clinical judgment is necessary.

© 2021 Therapeutic Research Center, LLC

Keep exploring
Yerba Mate monograph › Uses, safety, and every drug interaction in one place Exemestane supplement interactions › Every supplement checked against Exemestane, ranked by severity Exemestane drug information › The full plain-English guide to this medication Supplement interaction checker › Check any supplement or product against your medications Browse medications A–Z › Every drug we've checked against herbs & supplements Ask a pharmacist › Free, personal answer from our licensed team
Pharmacist Counseling Corner

Taking Yerba Mate and Exemestane Together: Common Questions

Can you take Yerba Mate with Exemestane?
There is only a minor interaction, which is usually not serious. Read the full details on this page and confirm with your pharmacist before combining them.
How serious is the Yerba Mate and Exemestane interaction?
We rate it Minor. This interaction is generally not clinically significant, but it remains worth noting and discussing with your pharmacist.

Written and reviewed by the HelloPharmacist editorial staff. Our editorial policy

Still Have a Question About Exemestane and Yerba Mate?

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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.