Drug & supplement interaction

Thyme + Conjugated Estrogens

Conjugated Estrogens brand names: Premarin, Cenestin, Enjuvia, Premarin Vaginal Cream.

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

Thyme has a moderate interaction with Conjugated Estrogens. Theoretically, thyme might competitively inhibit the effects of estrogen replacement therapy.

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

Thyme and Conjugated Estrogens

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

Moderate

ESTROGENS

Why this applies to Conjugated Estrogens

Conjugated Estrogens falls under ESTROGENS — the group Thyme interacts with.

Theoretically, thyme might competitively inhibit the effects of estrogen replacement therapy.
In vitro research shows that thyme has estrogen receptor-binding activity and phytoestrogen content. However, this effect has not been observed in humans.
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 short version: thyme contains plant compounds (phytoestrogens) that can latch onto the same receptors your conjugated estrogens (like Premarin) work on. In a test tube, thyme seems to compete for those spots, which in theory could blunt some of the benefit you get from your estrogen, things like relief from hot flashes, night sweats, or vaginal dryness.

The big caveat: this has only been seen in lab dishes, never proven in real people. The amount of thyme you cook with is very unlikely to cause any problem. Concentrated thyme supplements or extracts are the bigger question mark. If you're considering one regularly, just run it by your pharmacist or doctor first so they can keep an eye on how well your estrogen is working.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Zava DT, Dollbaum CM, Blen M. Estrogen and progestin bioactivity of foods, herbs, and spices. Proc Soc Exp Biol Med 1998;217:369-78. 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

Thyme Also Interacts With Other Medications

Thyme has 378 moderate known drug interactions in our database — the Conjugated Estrogens one above is one of them. If you take anything else, check it against the full list below.

Moderate 378 No known interaction 2,452 (incl. Conjugated Estrogens)
Taking anything else?

Check Another of Your Medications Against Thyme

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

Everything else you take

See Every Supplement That Interacts With Conjugated Estrogens

This page covers Thyme only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Conjugated Estrogens page lists 207 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), Tiratricol (major) and Acacia Rigidula (moderate).

By severity: 4 major · 172 moderate · 31 minor.

From our pharmacist’s overview on the Conjugated Estrogens page

“Conjugated estrogens (Premarin, Cenestin) are hormone replacement, most often for menopause symptoms, and the 207 supplements here warrant real care before adding any of them. Most of the risk runs through drug processing: 121 entries involve the CYP3A4 enzyme that clears estrogen, which is how St.”

Reviewed by 2 · Jul 18, 2026

Open the Conjugated Estrogens interaction page

One more smart check

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

We hold 708 real supplement products containing Thyme, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Thyme. Your product may carry other ingredients that interact with Conjugated Estrogens too, on top of Thyme — 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 Thyme and Conjugated Estrogens 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 Thyme
Top 25%

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

29 days ago today
Medication Conjugated Estrogens
Steady interest

#1,492 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 Thyme

What is Thyme?

Thyme
  • Cough and respiratory congestion
  • Sore throat
  • Digestive upset
  • Antimicrobial and antiseptic uses
  • Flavoring in cooking

Thyme is a common kitchen herb that has long been used for coughs, sore throats, and digestive complaints. It is generally safe in the amounts found in food, and some cough products that combine thyme with other herbs have modest supporting evidence, but high-quality research on thyme alone is limited. The concentrated essential oil should never be swallowed undiluted.

Read the full Thyme monograph & all interactions
Keep checking

Other Drugs & Thyme

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

0Major
378Moderate
0Minor
2,451No known interaction
378 Moderate 2,451 No interaction
Moderate

378 interactions

Showing 60 of 378 moderate interactions — see all 378 on the Thyme page.

No interaction 2,451 drugs checked — show the list

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

Showing the 60 most looked-up of 2,451 medications checked with no known interaction — see the full Thyme list.

See the full Thyme interactions page
See every supplement checked against Conjugated Estrogens, 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
Thyme monograph › Uses, safety, and every drug interaction in one place Conjugated Estrogens supplement interactions › Every supplement checked against Conjugated Estrogens, 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 Thyme and Conjugated Estrogens Together: Common Questions

Can you take Thyme with Conjugated Estrogens?
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 Thyme and Conjugated Estrogens 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 Conjugated Estrogens and Thyme?

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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.