Drug & supplement interaction

Vitex Agnus-castus + Ethinyl Estradiol, Norethindrone

Ethinyl Estradiol, Norethindrone brand names: Femhrt, Loestrin 21, Ovcon 35 21, Ovcon 50 28, Necon 0.5 35 21, and others.

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

Ethinyl Estradiol, Norethindrone falls into 2 drug categories that Vitex Agnus-castus can interact with; the most serious is rated moderate. Theoretically, vitex agnus-castus could interfere with oral contraceptives.

Read the full interaction report
SeverityModerate
LikelihoodPossible
Interactions2
EvidenceB
What do Severity, Likelihood & Evidence mean?
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Interaction report

Vitex Agnus-castus and Ethinyl Estradiol, Norethindrone

These two interact in 2 distinct ways. Each one is explained separately below.

Why Are There 2 Interactions?

Vitex Agnus-castus interacts with whole categories of medication. Ethinyl Estradiol, Norethindrone falls into 2 of those categories, so it can interact with Vitex Agnus-castus in 2 different ways. We’ve listed each one below — your overall risk is driven by the most serious of them (Moderate).

Moderate

CONTRACEPTIVE DRUGS

1 of 2

Why this applies to Ethinyl Estradiol, Norethindrone

Ethinyl Estradiol, Norethindrone falls under CONTRACEPTIVE DRUGS — the group Vitex Agnus-castus interacts with.

Theoretically, vitex agnus-castus could interfere with oral contraceptives.
Vitex agnus-castus might interfere with the efficacy of oral contraceptives due to possible hormone modulating activity.
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 thing to know if you're taking Loestrin, Ovcon, or a similar birth control pill that combines ethinyl estradiol and norethindrone. Vitex (chasteberry) is thought to nudge your body's hormone signals by acting on the pituitary gland and dopamine, which can shift levels of prolactin and other reproductive hormones. Your pill works by keeping your hormones in a steady, controlled balance, so anything that tinkers with that same system could, in theory, make the pill work less reliably.

I want to be honest that this concern is theoretical and not proven in people, so don't panic. But because a weakened pill can mean breakthrough bleeding or, more importantly, an unintended pregnancy, please check with your pharmacist or doctor before combining them.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Liu J, Burdette JE, Xu H, et al. Evaluation of estrogenic activity of plant extracts for the potential treatment of menopausal symptoms. J Agric Food Chem 2001;49:2472-9.. PubMed
  2. Wuttke W, Jarry H, Christoffel V, et al. Chaste tree (Vitex agnus-castus)--pharmacology and clinical indications. Phytomedicine 2003;10:348-57. PubMed
Moderate

ESTROGENS

2 of 2

Ethinyl Estradiol, Norethindrone also falls under ESTROGENS.

Theoretically, vitex agnus-castus could interfere with the activity of estrogens.
Vitex agnus-castus has hormone modulating activity that can interfere with the efficacy of hormone replacement therapy.
Severity Moderate Likelihood Probable Evidence D

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

Your pill, which combines ethinyl estradiol and norethindrone, works by delivering steady hormone levels, whether you're using it for birth control or as part of hormone therapy. Vitex (chasteberry) is a hormone-active herb that nudges your body's own reproductive hormones, partly by acting on the pituitary gland and lowering prolactin. In theory, mixing the two could throw off the hormone balance your pill is trying to maintain.

I want to be honest about the evidence here: this concern comes from lab and animal research, not real-world studies in people, so it's more theoretical than proven. Still, because reliable hormone levels matter (especially for pregnancy prevention), it's worth a quick chat with your pharmacist or doctor before adding Vitex. Don't stop or change anything on your own.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Liu J, Burdette JE, Xu H, et al. Evaluation of estrogenic activity of plant extracts for the potential treatment of menopausal symptoms. J Agric Food Chem 2001;49:2472-9.. PubMed
  2. Wuttke W, Jarry H, Christoffel V, et al. Chaste tree (Vitex agnus-castus)--pharmacology and clinical indications. Phytomedicine 2003;10:348-57. 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

Vitex Agnus-castus Also Interacts With Other Medications

Vitex Agnus-castus has 120 moderate known drug interactions in our database — the Ethinyl Estradiol, Norethindrone one above is among them. If you take anything else, check it against the full list below.

Moderate 120 No known interaction 2,710 (incl. Ethinyl Estradiol, Norethindrone)
Taking anything else?

Check Another of Your Medications Against Vitex Agnus-castus

Covers the 2,830 medications we’ve checked against Vitex Agnus-castus. Pick one to open its full report.

Everything else you take

See Every Supplement That Interacts With Ethinyl Estradiol, Norethindrone

This page covers Vitex Agnus-castus only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Ethinyl Estradiol, Norethindrone page lists 240 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 · 196 moderate · 38 minor.

From our pharmacist’s overview on the Ethinyl Estradiol, Norethindrone page

“If you take a birth control pill or hormone therapy containing ethinyl estradiol and norethindrone (Loestrin, Femhrt, and others), a few supplements can genuinely undermine it, so read this page with care. Six of the 240 ingredients on file are rated major, and those six come first.”

Reviewed by 2 · Jul 18, 2026

Open the Ethinyl Estradiol, Norethindrone interaction page

One more smart check

Taking Vitex Agnus-castus as Part of a Dietary Supplement Product? Check It for Interactions

We hold 45 real supplement products containing Vitex Agnus-castus, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Vitex Agnus-castus. Your product may carry other ingredients that interact with Ethinyl Estradiol, Norethindrone too, on top of Vitex Agnus-castus — 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 Vitex Agnus-castus and Ethinyl Estradiol, Norethindrone 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 Vitex Agnus-castus
Steady interest

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

29 days ago today
Medication Ethinyl Estradiol, Norethindrone
Top 10%

#250 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 Vitex Agnus-castus

What is Vitex Agnus-castus?

Vitex Agnus-castus
  • Premenstrual syndrome (PMS)
  • Irregular or absent menstrual periods
  • Cyclical breast pain (mastalgia)
  • Menopause symptoms
  • Fertility support

Vitex (chasteberry) is an herbal remedy most often used for PMS and menstrual cycle problems, and the strongest evidence is for easing some PMS symptoms. It is generally well tolerated by many adults, but it can affect hormone-related processes, so anyone who is pregnant, breastfeeding, or has a hormone-sensitive condition should talk with a healthcare professional first.

Read the full Vitex Agnus-castus monograph & all interactions
Keep checking

Other Drugs & Vitex Agnus-castus

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

0Major
120Moderate
0Minor
2,709No known interaction
120 Moderate 2,709 No interaction
Moderate

120 interactions

Showing 60 of 120 moderate interactions — see all 120 on the Vitex Agnus-castus page.

No interaction 2,709 drugs checked — show the list

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

Showing the 60 most looked-up of 2,709 medications checked with no known interaction — see the full Vitex Agnus-castus list.

See the full Vitex Agnus-castus interactions page
See every supplement checked against Ethinyl Estradiol, Norethindrone, 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
Vitex Agnus-castus monograph › Uses, safety, and every drug interaction in one place Ethinyl Estradiol, Norethindrone supplement interactions › Every supplement checked against Ethinyl Estradiol, Norethindrone, 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 Vitex Agnus-castus and Ethinyl Estradiol, Norethindrone Together: Common Questions

Can you take Vitex Agnus-castus with Ethinyl Estradiol, Norethindrone?
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 2 interactions listed for Vitex Agnus-castus and Ethinyl Estradiol, Norethindrone?
Ethinyl Estradiol, Norethindrone belongs to more than one drug category, and Vitex Agnus-castus 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 Vitex Agnus-castus and Ethinyl Estradiol, Norethindrone 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.