Drug & supplement interaction

Ginkgo + Ethinyl Estradiol, Levonorgestrel

Ethinyl Estradiol, Levonorgestrel brand names: Levlite 28, Tri-Levlen 21, Tri-Levlen 28, Levlite, Trivora-28, and others.

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

Ethinyl Estradiol, Levonorgestrel falls into 3 drug categories that Ginkgo can interact with; the most serious is rated moderate. Theoretically, ginkgo might increase levels of drugs metabolized by CYP1A2.

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

Ginkgo and Ethinyl Estradiol, Levonorgestrel

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

Why Are There 3 Interactions?

Ginkgo interacts with whole categories of medication. Ethinyl Estradiol, Levonorgestrel falls into 3 of those categories, so it can interact with Ginkgo 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) SUBSTRATES

1 of 3

Why this applies to Ethinyl Estradiol, Levonorgestrel

Ethinyl Estradiol, Levonorgestrel falls under CYTOCHROME P450 1A2 (CYP1A2) SUBSTRATES — the group Ginkgo interacts with.

Theoretically, ginkgo might increase levels of drugs metabolized by CYP1A2.
Laboratory research suggests that ginkgo leaf extract can mildly inhibit CYP1A2 enzymes. However, clinical research suggests ginkgo might not affect CYP1A2. Until more is known, use ginkgo cautiously in patients taking drugs metabolized by these enzymes.
Severity Moderate 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 the short version: your birth control pill (ethinyl estradiol with levonorgestrel) is partly broken down by a liver enzyme called CYP1A2. In a test tube, ginkgo seems to mildly slow that enzyme, which in theory could let a bit more of the estrogen hang around in your body. If that happened, you might notice more of the usual estrogen-type effects like nausea, breast tenderness, or bloating.

The good news is that real human studies haven't clearly shown ginkgo actually changing these levels, so this stays mostly theoretical and on the milder side. Your pill is not a prodrug, so it still works to prevent pregnancy. I wouldn't lose sleep over it, but it's worth a quick mention to your pharmacist or doctor before adding ginkgo, especially since ginkgo can also thin the blood.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Gurley BJ, Gardner SF, Hubbard MA. Clinical assessment of potential cytochrome P450-mediated herb-drug interactions. AAPS Ann Mtg & Expo Indianapolis, IN: 2000; Oct 29 - Nov 2:presentation #3460.
  2. Galluzzi S, Zanetti O, Binetti G, et al. Coma in a patient with Alzheimer's disease taking low dose trazodone and Ginkgo biloba. J Neurol Neurosurg Psychiatry 2000;68:679-80. DOI
  3. Budzinski JW, Foster BC, Vandenhoek S, Arnason JT. An in vitro evaluation of human cytochrome P450 3A4 inhibition by selected commercial herbal extracts and tinctures. Phytomedicine 2000;7:273-82. PubMed
  4. Gurley BJ, Gardner SF, Hubbard MA, et al. Cytochrome P450 phenotypic ratios for predicting herb-drug interactions in humans. Clin Pharmacol Ther 2002;72:276-87.. PubMed
Moderate

CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES

2 of 3

Ethinyl Estradiol, Levonorgestrel also falls under CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES.

Theoretically, ginkgo might decrease levels of drugs metabolized by CYP3A4.
There is conflicting evidence about whether ginkgo induces or inhibits CYP3A4. Ginkgo does not appear to affect hepatic CYP3A4. However, it is not known if ginkgo affects intestinal CYP3A4. Preliminary clinical research suggests that taking ginkgo does not significantly affect levels of donepezil, lopinavir, or ritonavir, which are all CYP3A4 substrates. Other clinical research also suggests ginkgo does not significantly affect CYP3A4 activity. However, there are two case reports of decreased efavirenz concentrations and increased viral load in patients taking ginkgo. It is suspected that terpenoids from the ginkgo extract reduced drug levels by inducing cytochrome P450 3A4 (CYP3A4).
Severity Moderate 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 the gist for your birth control pill (the ethinyl estradiol and levonorgestrel combo). These hormones are partly cleared by a liver enzyme called CYP3A4. The concern on file is mostly theoretical, and the evidence is genuinely mixed. If ginkgo nudges that enzyme to work faster, it could lower hormone levels a bit, which in turn could make the pill slightly less reliable at preventing pregnancy. You might also notice more breakthrough spotting if levels dip.

Honestly, most studies suggest ginkgo doesn't strongly affect this enzyme, so this isn't a high-alarm situation. Still, since we're talking about preventing pregnancy, I'd run it past your pharmacist or doctor before combining them so you can decide together.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Gurley BJ, Gardner SF, Hubbard MA. Clinical assessment of potential cytochrome P450-mediated herb-drug interactions. AAPS Ann Mtg & Expo Indianapolis, IN: 2000; Oct 29 - Nov 2:presentation #3460.
  2. Galluzzi S, Zanetti O, Binetti G, et al. Coma in a patient with Alzheimer's disease taking low dose trazodone and Ginkgo biloba. J Neurol Neurosurg Psychiatry 2000;68:679-80. DOI
  3. Budzinski JW, Foster BC, Vandenhoek S, Arnason JT. An in vitro evaluation of human cytochrome P450 3A4 inhibition by selected commercial herbal extracts and tinctures. Phytomedicine 2000;7:273-82. PubMed
  4. Gurley BJ, Gardner SF, Hubbard MA, et al. Cytochrome P450 phenotypic ratios for predicting herb-drug interactions in humans. Clin Pharmacol Ther 2002;72:276-87.. PubMed
  5. Yale SH, Glurich I. Analysis of the inhibitory potential of Ginkgo biloba, Echinacea purpurea, and Serenoa repens on the metabolic activity of cytochrome P450 3A4, 2D6, and 2C9. J Altern Complement Med 2005;11:433-9.
  6. Yasui-Furukori N, Furukori H, Kaneda A, et al. The effects of Ginkgo biloba extracts on the pharmacokinetics and pharmacodynamics of donepezil. J Clin Pharmacol 2004;44:538-42.
  7. Markowitz JS, Donovan JL, Lindsay DeVane C, et al. Multiple-dose administration of Ginkgo biloba did not affect cytochrome P-450 2D6 or 3A4 activity in normal volunteers. J Clin Psychopharmacol 2003;23:576-81. PubMed
  8. Wiegman DJ, Brinkman K, Franssen EJ. Interaction of Ginkgo biloba with efavirenz. AIDS 2009;23:1184-5. PubMed
  9. Naccarato M, Yoong D, Gough K. A potential drug-herbal interaction between Ginkgo biloba and efavirenz. J Int Assoc Physicians AIDS Care (Chic). 2012;11(2):98-100. doi: 10.1177/1545109711435364. Epub 2012 Feb 9.
  10. Robertson, S. M., Davey, R. T., Voell, J., Formentini, E., Alfaro, R. M., and Penzak, S. R. Effect of Ginkgo biloba extract on lopinavir, midazolam and fexofenadine pharmacokinetics in healthy subjects. Curr Med Res Opin 2008;24(2):591-599. PubMed
  11. Penzak, S. R., Busse, K. H., Robertson, S. M., Formentini, E., Alfaro, R. M., and Davey, R. T., Jr. Limitations of using a single postdose midazolam concentration to predict CYP3A-mediated drug interactions. J Clin Pharmacol 2008;48(6):671-680. PubMed
  12. Jalloh MA, Gregory PJ, Hein D, et al. Dietary supplement interactions with antiretrovirals: a systematic review. Int J STD AIDS. 2017 Jan;28(1):4-15. PubMed
  13. Bai J, Zhang C. Metabolic interaction between biflavonoids in Ginkgo biloba leaves and tacrolimus. Biopharm Drug Dispos 2023;44(2):157-164.
Moderate

P-GLYCOPROTEIN SUBSTRATES

3 of 3

Ethinyl Estradiol, Levonorgestrel also falls under P-GLYCOPROTEIN SUBSTRATES.

Theoretically, taking ginkgo with P-glycoprotein substrates might increase the levels and adverse effects of these substrates.
A small clinical study in healthy volunteers shows that using ginkgo leaf extract 120 mg orally three times daily for 14 days can increase levels of the P-glycoprotein substrate, talinolol, by 36% in healthy male individuals. However, single doses of ginkgo do not have the same effect.
Severity Moderate 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

Your birth control pill (the ethinyl estradiol and levonorgestrel combo) is handled in part by a cellular pump called P-glycoprotein, which helps move drugs in and out of your gut and other tissues. Ginkgo can mildly slow that pump down. In theory, that could let a little more of the hormones build up in your system, which might mean slightly more of the usual estrogen-related side effects like nausea, breast tenderness, headaches, or spotting.

Honestly though, this is a fairly weak and mostly theoretical concern. The evidence comes from a small study using a different drug, and the effect was modest. This is not a dangerous combination, but it is worth mentioning to your pharmacist or doctor, especially if you notice new side effects. Don't change anything on your own.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Fan, L., Tao, G. Y., Wang, G., Chen, Y., Zhang, W., He, Y. J., Li, Q., Lei, H. P., Jiang, F., Hu, D. L., Huang, Y. F., and Zhou, H. H. Effects of Ginkgo biloba extract ingestion on the pharmacokinetics of talinolol in healthy Chinese volunteers. Ann Phar 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

Ginkgo Also Interacts With Other Medications

Ginkgo has 1 major, 1,264 moderate known drug interactions in our database — the Ethinyl Estradiol, Levonorgestrel one above is among them. If you take anything else, check it against the full list below.

Major 1 Moderate 1,264 No known interaction 1,565 (incl. Ethinyl Estradiol, Levonorgestrel)
Taking anything else?

Check Another of Your Medications Against Ginkgo

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

From our Q&A

Questions About Ginkgo or Ethinyl Estradiol, Levonorgestrel

These are real questions from readers, answered by the pharmacists at HelloPharmacist — written by a person, not generated from a database. Each one covers Ginkgo or Ethinyl Estradiol, Levonorgestrel, 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 Ethinyl Estradiol, Levonorgestrel

This page covers Ginkgo only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Ethinyl Estradiol, Levonorgestrel page lists 239 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 · 195 moderate · 38 minor.

Open the Ethinyl Estradiol, Levonorgestrel interaction page

One more smart check

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

We hold 4,399 real supplement products containing Ginkgo, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Ginkgo. Your product may carry other ingredients that interact with Ethinyl Estradiol, Levonorgestrel too, on top of Ginkgo — 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 Ginkgo and Ethinyl 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 Ginkgo
Top 5%

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

29 days ago today
Medication Ethinyl Estradiol, Levonorgestrel
Top 25%

#431 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 Ginkgo

What is Ginkgo?

Ginkgo
  • Memory and cognitive support
  • Age-related mental decline
  • Circulation problems
  • Tinnitus (ringing in the ears)
  • Dizziness or vertigo

Ginkgo is one of the world's most popular herbal supplements, mostly taken to support memory and circulation. The evidence for these uses is mixed and generally weak, and it is not proven to prevent memory loss or dementia. It is usually well tolerated in healthy adults, but it can thin the blood, so talk to your pharmacist or doctor before using it.

Read the full Ginkgo monograph & all interactions
Keep checking

Other Drugs & Ginkgo

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

1Major
1,264Moderate
0Minor
1,564No known interaction
1 Major 1,264 Moderate 1,564 No interaction
Major

1 interaction

Moderate

1,264 interactions

Showing 60 of 1,264 moderate interactions — see all 1,264 on the Ginkgo page.

No interaction 1,564 drugs checked — show the list

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

Showing the 60 most looked-up of 1,564 medications checked with no known interaction — see the full Ginkgo list.

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

Can you take Ginkgo with Ethinyl 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 Ginkgo and Ethinyl Estradiol, Levonorgestrel?
Ethinyl Estradiol, Levonorgestrel belongs to more than one drug category, and Ginkgo 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 Ginkgo and Ethinyl 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.