Drug & supplement interaction

Oolong Tea + Ethiny Estradiol, Levonorgestrel

Ethiny Estradiol, Levonorgestrel brand names: Logynon, Microgynon 30 ED.

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

Ethiny Estradiol, Levonorgestrel falls into 3 drug categories that Oolong Tea can interact with; the most serious is rated moderate. Theoretically, concomitant use might increase the levels and adverse effects of the caffeine in oolong tea.

Read the full interaction report
SeverityModerate
LikelihoodPossible
Interactions3
EvidenceD
What do Severity, Likelihood & Evidence mean?
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Interaction report

Oolong Tea and Ethiny Estradiol, Levonorgestrel

These two interact in 3 distinct ways. Each one is explained separately below.

Why Are There 3 Interactions?

Oolong Tea interacts with whole categories of medication. Ethiny Estradiol, Levonorgestrel falls into 3 of those categories, so it can interact with Oolong Tea in 3 different ways. We’ve listed each one below — your overall risk is driven by the most serious of them (Moderate).

Moderate

CYTOCHROME P450 1A2 (CYP1A2) INHIBITORS

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Why this applies to Ethiny Estradiol, Levonorgestrel

Ethiny Estradiol, Levonorgestrel falls under CYTOCHROME P450 1A2 (CYP1A2) INHIBITORS — the group Oolong Tea interacts with.

Theoretically, concomitant use might increase the levels and adverse effects of the caffeine in oolong tea.
Oolong tea contains caffeine. Caffeine is metabolized by cytochrome P450 1A2 (CYP1A2),. Theoretically, drugs that inhibit CYP1A2 may decrease the clearance rate of caffeine from oolong tea and increase caffeine levels.
Severity Moderate 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 thing to keep in mind with your birth control pill (the ethinyl estradiol and levonorgestrel combo in Microgynon or Logynon). The estrogen part can mildly slow down the same liver enzyme (CYP1A2) that breaks down the caffeine in oolong tea. So the tea isn't changing how well your pill works. It's the other way around: your pill may let caffeine hang around a little longer in your system.

In plain terms, your usual cup of oolong might feel a bit stronger than expected, so you could notice things like jitteriness, a racing heart, trouble sleeping, or feeling wired. This is theoretical and based on how the body processes things, not hard proof. A regular cup or two is unlikely to be a big deal. If caffeine bothers you, just cut back and chat with your pharmacist.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Weisburger JH. Tea and health: the underlying mechanisms. Proc Soc Exp Biol Med 1999;220:271-5. PubMed
  2. Hagg S, Spigset O, Mjorndal T, Dahlqvist R. Effect of caffeine on clozapine pharmacokinetics in healthy volunteers. Br J Clin Pharmacol 2000;49:59-63. PubMed
  3. Carrillo JA, Benitez J. Clinically significant pharmacokinetic interactions between dietary caffeine and medications. Clin Pharmacokinet 2000;39:127-53. PubMed
  4. Kot, M. and Daniel, W. A. Effect of diethyldithiocarbamate (DDC) and ticlopidine on CYP1A2 activity and caffeine metabolism: an in vitro comparative study with human cDNA-expressed CYP1A2 and liver microsomes. Pharmacol Rep. 2009;61(6):1216-1220. PubMed
  5. Wojcikowski, J. and Daniel, W. A. Perazine at therapeutic drug concentrations inhibits human cytochrome P450 isoenzyme 1A2 (CYP1A2) and caffeine metabolism--an in vitro study. Pharmacol Rep. 2009;61(5):851-858. PubMed
  6. Wang, X. and Yeung, J. H. Effects of the aqueous extract from Salvia miltiorrhiza Bunge on caffeine pharmacokinetics and liver microsomal CYP1A2 activity in humans and rats. J Pharm Pharmacol 2010;62(8):1077-1083.
  7. Kot M, Daniel WA. Caffeine as a marker substrate for testing cytochrome P450 activity in human and rat. Pharmacol Rep 2008;60:789-97.
  8. Kjaerstad MB, Nielsen F, Nohr-Jensen L, et al. Systemic uptake of miconazole during vaginal suppository use and effect on CYP1A2 and CYP3A4 associated enzyme activities in women. Eur J Clin Pharmacol 2010;66:1189-97. PubMed
  9. Goh BC, Reddy NJ, Dandamudi UB, et al. An evaluation of the drug interaction potential of pazopanib, an oral vascular endothelial growth factor receptor tyrosine kinase inhibitor, using a modified Cooperstown 5+1 cocktail in patients with advanced solid t
  10. Chen Y, Kang Z, Yan J, et al. Liu wei di huang wan, a well-known traditional Chinese medicine induces CYP1A2 while suppressing CYP2A6 and N-acetyltransferase 2 acivities in man. J Ethnopharmacol 2010;132:213-8.
  11. Suzuki S, Murayama Y, Sugiyama E, et al. Estimating pediatric doses of drugs metabolized by cytochrome P450 (CYP) isozymes, based on physiological liver development and serum protein levels. Yakugaku Zasshi 2010;130:613-20. PubMed
  12. Chien CF, Wu YT, Lee WC, et al. Herb-drug interaction of Andrographis paniculata extract and andrographolide on the pharmacokinetics of theophylline in rats. Chem Biol Interact 2010;184:458-65. PubMed
  13. Mills BM, Zaya MJ, Walters RR, et al. Current cytochrome P450 phenotyping methods applied to metabolic drug -drug interaction prediction in dogs. Drug Metab Dispos 2010;38:396-404. PubMed
  14. Turpault S, Brian W, Van Horn R, et al. Pharmacokinetic assessment of a five-probe cocktail for CYPs 1A2, 2C9, 2C19, 2D6, and 3A. Br J Clin Pharmacol 2009;68:928-35. PubMed
  15. Filimonova AA, Ziganshina LE, Ziganshin AU, Chichirov AA. On the possibility of patient phenotyping on the basis of cytochrome p-450 1A2 isoenzyme activity using caffeine as the test substrate. Eksp Klin Farmakol 2009;72:61-5.
  16. Jenkins J, Williams D, Deng Y, et al. Eltrombopag, an oral thrombopoietin receptor agonist, has no impact on the pharmacokinetic profile of probe drugs for cytochrome P450 isoenzymes CYP3A4, CYP1A2, CYP2C9 and CYP2C19 in healthy men: a cocktail analysis.
  17. Perera, V., Gross, A. S., and McLachlan, A. J. Caffeine and paraxanthine HPLC assay for CYP1A2 phenotype assessment using saliva and plasma. Biomed.Chromatogr. 2010;24(10):1136-1144. PubMed
  18. Izzo, A. A. and Ernst, E. Interactions between herbal medicines and prescribed drugs: an updated systematic review. Drugs 2009;69(13):1777-1798. PubMed
Moderate

ESTROGENS

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Ethiny Estradiol, Levonorgestrel also falls under ESTROGENS.

Theoretically, estrogens might increase the levels and adverse effects of caffeine in oolong tea.
Oolong tea contains caffeine. Estrogen inhibits caffeine metabolism.
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 something a little different about this pairing. It isn't that your oolong tea changes how well your birth control (the ethinyl estradiol and levonorgestrel in Microgynon or Logynon) works. It's the other way around. The estrogen in your pill can slow down how your body clears caffeine, so the caffeine from your tea sticks around longer than usual.

In plain terms, a couple of cups might hit you a bit harder. You may notice more jitteriness, a faster heartbeat, trouble sleeping, or feeling restless. This is considered a mild, manageable effect, not a dangerous one, and you don't need to give up your tea. If caffeine seems to bother you more than it used to, just trim back a bit or check in with your pharmacist.

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
Minor

CONTRACEPTIVE DRUGS

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Ethiny Estradiol, Levonorgestrel also falls under CONTRACEPTIVE DRUGS.

Theoretically, concomitant use might increase the effects and adverse effects of caffeine in oolong tea.
Oolong tea contains caffeine. Oral contraceptives decrease the rate of caffeine clearance by 40% to 65%.
Severity Minor Likelihood Possible Evidence B

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 a small twist worth knowing about. Your birth control pill (the ethinyl estradiol and levonorgestrel in Microgynon or Logynon) doesn't lose any of its effectiveness from oolong tea. Instead, it works the other way around: the estrogen in your pill slows down how fast your body clears caffeine, by roughly 40 to 65 percent. That means the caffeine from your tea hangs around longer than it normally would.

In real life, that can show up as feeling a bit more jittery, a faster heartbeat, trouble sleeping, or feeling restless, especially if you drink several cups. This is a minor, fairly theoretical effect, and a cup or two is usually no big deal. If caffeine tends to bother you, just go easier on it and chat with your pharmacist if you have questions.

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

Oolong Tea Also Interacts With Other Medications

Oolong Tea has 8 major, 517 moderate, 126 minor known drug interactions in our database — the Ethiny Estradiol, Levonorgestrel one above is among them. If you take anything else, check it against the full list below.

Major 8 Moderate 517 Minor 126 No known interaction 2,179 (incl. Ethiny Estradiol, Levonorgestrel)
Taking anything else?

Check Another of Your Medications Against Oolong Tea

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

Everything else you take

See Every Supplement That Interacts With Ethiny Estradiol, Levonorgestrel

This page covers Oolong Tea only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Ethiny Estradiol, Levonorgestrel page lists 214 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), Acacia Rigidula (moderate) and Adrafinil (moderate).

By severity: 3 major · 171 moderate · 40 minor.

From our pharmacist’s overview on the Ethiny Estradiol, Levonorgestrel page

“A supplement that lowers hormone levels in a birth control pill can mean an unplanned pregnancy, and St. John's wort can do exactly that to ethinyl estradiol and levonorgestrel (Logynon, Microgynon 30 ED) by speeding up how your liver clears the hormones.”

Reviewed by 2 · Jul 18, 2026

Open the Ethiny Estradiol, Levonorgestrel interaction page

One more smart check

Taking Oolong Tea as Part of a Dietary Supplement Product? Check It for Interactions

We hold 75 real supplement products containing Oolong Tea, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Oolong Tea. Your product may carry other ingredients that interact with Ethiny Estradiol, Levonorgestrel too, on top of Oolong Tea — 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 Oolong Tea and Ethiny Estradiol, Levonorgestrel 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 Oolong Tea
Steady interest

#1,144 of 1,452 supplements looked up here in the last 7 days

29 days ago today
Medication Ethiny Estradiol, Levonorgestrel
Top 5%

#113 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 Oolong Tea

What is Oolong Tea?

  • Weight management
  • Mental alertness and energy
  • Heart health
  • Blood sugar support
  • Antioxidant support

Oolong tea is a traditional partially oxidized tea made from the same plant as green and black tea, and it provides caffeine and plant antioxidants. As a beverage it is generally considered safe for most healthy adults in moderate amounts, but evidence for specific health benefits like weight loss or blood sugar control is limited. If you have heart, blood pressure, or caffeine-sensitivity concerns, talk with your pharmacist or doctor.

Read the full Oolong Tea monograph & all interactions
Keep checking

Other Drugs & Oolong Tea

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

8Major
517Moderate
126Minor
2,178No known interaction
8 Major 517 Moderate 126 Minor 2,178 No interaction
Major

8 interactions

Moderate

517 interactions

Showing 60 of 517 moderate interactions — see all 517 on the Oolong Tea page.

Minor

126 interactions

Showing 60 of 126 minor interactions — see all 126 on the Oolong Tea page.

No interaction 2,178 drugs checked — show the list

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

Showing the 60 most looked-up of 2,178 medications checked with no known interaction — see the full Oolong Tea list.

See the full Oolong Tea interactions page
See every supplement checked against Ethiny Estradiol, Levonorgestrel, 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
Oolong Tea monograph › Uses, safety, and every drug interaction in one place Ethiny Estradiol, Levonorgestrel supplement interactions › Every supplement checked against Ethiny Estradiol, Levonorgestrel, 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 Oolong Tea and Ethiny Estradiol, Levonorgestrel Together: Common Questions

Can you take Oolong Tea with Ethiny Estradiol, Levonorgestrel?
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.
Why are there 3 interactions listed for Oolong Tea and Ethiny Estradiol, Levonorgestrel?
Ethiny Estradiol, Levonorgestrel belongs to more than one drug category, and Oolong Tea interacts with each of those categories a little differently. We list every one so nothing is missed — your overall risk is driven by the most serious of them.
How serious is the Oolong Tea and Ethiny Estradiol, Levonorgestrel 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

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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.