Drug & supplement interaction

Ilex Guayusa + Mestranol, Norethynodrel

Mestranol, Norethynodrel brand name: Enovid-E.

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

Ilex Guayusa has a moderate interaction with Mestranol, Norethynodrel. Theoretically, concomitant use might increase the effects and adverse effects of caffeine found in Ilex guayusa.

Read the full interaction report
SeverityModerate
LikelihoodProbable
EvidenceB
What do Severity, Likelihood & Evidence mean?
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Interaction report

Ilex Guayusa and Mestranol, Norethynodrel

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

Moderate

CONTRACEPTIVE DRUGS

Why this applies to Mestranol, Norethynodrel

Mestranol, Norethynodrel falls under CONTRACEPTIVE DRUGS — the group Ilex Guayusa interacts with.

Theoretically, concomitant use might increase the effects and adverse effects of caffeine found in Ilex guayusa.
Ilex guayusa contains caffeine. Oral contraceptives decrease the rate of caffeine clearance by 40% to 65%.
Severity Moderate Likelihood Probable Evidence B

Interaction 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..

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

Here's a flip on what you might expect: in this case, it's your birth control pill (Enovid-E, which combines mestranol and norethynodrel) that changes how your body handles the caffeine in guayusa, not the other way around. The estrogen in these pills slows down how fast you clear caffeine, by roughly 40 to 65 percent. So the same cup of guayusa tea can hang around longer and hit harder than usual.

What that feels like in real life: more jitters, a racing or pounding heart, trouble sleeping, anxious feelings, or an upset stomach. Your pill itself still works fine for birth control. If you notice you're more wired than normal, simply cutting back on caffeine usually does the trick. Chat with your pharmacist if you're unsure how much is too much.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Pollock BG, Wylie M, Stack JA, et al. Inhibition of caffeine metabolism by estrogen replacement therapy in postmenopausal women. J Clin Pharmacol 1999;39:936-40. PubMed
  2. Abernethy DR, Todd EL. Impairment of caffeine clearance by chronic use of low-dose oestrogen-containing oral contraceptives. Eur J Clin Pharmacol 1985;28:425-8. 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

Ilex Guayusa Also Interacts With Other Medications

Ilex Guayusa has 8 major, 469 moderate, 127 minor known drug interactions in our database — the Mestranol, Norethynodrel one above is one of them. If you take anything else, check it against the full list below.

Major 8 Moderate 469 Minor 127 No known interaction 2,226 (incl. Mestranol, Norethynodrel)
Taking anything else?

Check Another of Your Medications Against Ilex Guayusa

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

Everything else you take

See Every Supplement That Interacts With Mestranol, Norethynodrel

This page covers Ilex Guayusa only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Mestranol, Norethynodrel page lists 188 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Beer (major), Grapefruit (major), Siberian Cocklebur (major) and St. John's Wort (major).

By severity: 6 major · 140 moderate · 42 minor.

From our pharmacist’s overview on the Mestranol, Norethynodrel page

“The list for Mestranol and Norethynodrel (Enovid-E, a combined birth control pill) deserves genuine care, because several entries can quietly undo the pill itself. St.”

Reviewed by 2 · Jul 18, 2026

Open the Mestranol, Norethynodrel interaction page

How much people look this up

Where Ilex Guayusa and Mestranol, Norethynodrel 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 Ilex Guayusa
Steady interest

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

29 days ago today
Medication Mestranol, Norethynodrel
Steady interest

#1,723 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 Ilex Guayusa

What is Ilex Guayusa?

  • Energy and alertness
  • Mental focus
  • Antioxidant support
  • Appetite control
  • Athletic and physical performance

Ilex guayusa is a caffeine-containing holly leaf from the Amazon, traditionally brewed as a tea for energy and alertness, much like yerba mate or green tea. There is limited human research confirming specific health benefits, and its main reliable effect comes from its caffeine content. Because it is a stimulant, use it cautiously and check with your pharmacist or doctor if you have heart concerns or are pregnant.

Read the full Ilex Guayusa monograph & all interactions
Keep checking

Other Drugs & Ilex Guayusa

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

8Major
469Moderate
127Minor
2,225No known interaction
8 Major 469 Moderate 127 Minor 2,225 No interaction
Major

8 interactions

Moderate

469 interactions

Showing 60 of 469 moderate interactions — see all 469 on the Ilex Guayusa page.

Minor

127 interactions

Showing 60 of 127 minor interactions — see all 127 on the Ilex Guayusa page.

No interaction 2,225 drugs checked — show the list

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

Showing the 60 most looked-up of 2,225 medications checked with no known interaction — see the full Ilex Guayusa list.

See the full Ilex Guayusa interactions page
See every supplement checked against Mestranol, Norethynodrel, 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
Ilex Guayusa monograph › Uses, safety, and every drug interaction in one place Mestranol, Norethynodrel supplement interactions › Every supplement checked against Mestranol, Norethynodrel, 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 Ask a pharmacist › Free, personal answer from our licensed team
Pharmacist Counseling Corner

Taking Ilex Guayusa and Mestranol, Norethynodrel Together: Common Questions

Can you take Ilex Guayusa with Mestranol, Norethynodrel?
There is a moderate interaction, so it may be acceptable with monitoring or timing changes — but check with your pharmacist first. Read the full details on this page and confirm with your pharmacist before combining them.
How serious is the Ilex Guayusa and Mestranol, Norethynodrel interaction?
We rate it Moderate. This combination may require monitoring, a dose adjustment, or separating the times you take each one. Consult your pharmacist before using them together.

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

Still Have a Question About Mestranol, Norethynodrel and Ilex Guayusa?

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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.