Drug & supplement interaction

Dyer's Broom + Caffeine (OTC drug)

Caffeine (OTC drug) brand names: Vivarin, Overtime, Molie.

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

Dyer's Broom has a moderate interaction with Caffeine (OTC drug). Theoretically, dyer's broom might reduce the clearance of caffeine.

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

Dyer's Broom and Caffeine (OTC drug)

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

Moderate

CAFFEINE

Theoretically, dyer's broom might reduce the clearance of caffeine.
Dyer's broom contains genistein. Taking genistein 1 gram daily for 14 days seems to inhibit caffeine clearance and metabolism in healthy females. This effect has been attributed to inhibition of the cytochrome P450 1A2 (CYP1A2) enzyme, which is involved in caffeine metabolism. It is unclear if this effect occurs with the lower amounts of genistein found in dyer's broom.
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: dyer's broom contains a plant compound called genistein, which in the lab can slow down an enzyme (CYP1A2) that your body uses to clear caffeine. If that slowdown happened, caffeine could linger longer than usual, meaning a single cup of coffee or a caffeine pill might hit harder. Think jittery feeling, a racing or pounding heart, trouble sleeping, or feeling wired and anxious.

That said, this is really a theoretical concern. The studies used about 1 gram of pure genistein daily, far more than the trace amounts found in dyer's broom, so we honestly don't know if everyday use would matter. Still, if you take caffeine and are considering this supplement, run it by your pharmacist or doctor first.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Chen, Y., Xiao, C. Q., He, Y. J., Chen, B. L., Wang, G., Zhou, G., Zhang, W., Tan, Z. R., Cao, S., Wang, L. P., and Zhou, H. H. Genistein alters caffeine exposure in healthy female volunteers. Eur.J Clin.Pharmacol. 2011;67(4):347-353. 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

Dyer's Broom Also Interacts With Other Medications

Dyer's Broom has 28 moderate known drug interactions in our database — the Caffeine (OTC drug) one above is one of them. If you take anything else, check it against the full list below.

Moderate 28 No known interaction 2,802 (incl. Caffeine (OTC drug))
Taking anything else?

Check Another of Your Medications Against Dyer's Broom

Covers the 2,830 medications we’ve checked against Dyer's Broom. Pick one to open its full report.

Everything else you take

See Every Supplement That Interacts With Caffeine (OTC drug)

This page covers Dyer's Broom only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Caffeine (OTC drug) page lists 208 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Ephedra (major), Grapefruit (major), Peyote (major) and Rauvolfia Vomitoria (major).

By severity: 7 major · 155 moderate · 46 minor.

From our pharmacist’s overview on the Caffeine (OTC drug) page

“The person swallowing a caffeine pill like Vivarin to power through a shift is often the same person drinking coffee, taking an herbal energy blend, or scooping pre-workout powder, and that overlap is exactly where the danger sits. Seven of the 208 supplement ingredients on file carry a major rating, and those seven are worth understan…”

Reviewed by 2 · Jul 18, 2026

Open the Caffeine (OTC drug) interaction page

One more smart check

Taking Dyer's Broom as Part of a Dietary Supplement Product? Check It for Interactions

We hold 8 real supplement products containing Dyer's Broom, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Dyer's Broom. Your product may carry other ingredients that interact with Caffeine (OTC drug) too, on top of Dyer's Broom — 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 Dyer's Broom and Caffeine (OTC drug) 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 Dyer's Broom
Steady interest

#1,072 of 1,452 supplements looked up here in the last 7 days

29 days ago today
Medication Caffeine (OTC drug)
Top 25%

#328 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 Dyer's Broom

What is Dyer's Broom?

Dyer's Broom
  • Skin irritation
  • Respiratory complaints
  • Gout
  • Lower back and pelvic pain
  • Digestive upset
  • As a natural yellow dye

Dyer's broom is a European flowering plant best known historically as a source of yellow textile dye, with some traditional medicinal uses. There is very little reliable human research to support any health benefit, and it contains compounds that can be toxic in larger amounts, so it should be used cautiously, if at all. Talk to your pharmacist or doctor before trying it.

Read the full Dyer's Broom monograph & all interactions
Keep checking

Other Drugs & Dyer's Broom

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

0Major
28Moderate
0Minor
2,801No known interaction
28 Moderate 2,801 No interaction
Moderate

28 interactions

No interaction 2,801 drugs checked — show the list

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

Showing the 60 most looked-up of 2,801 medications checked with no known interaction — see the full Dyer's Broom list.

See the full Dyer's Broom interactions page
See every supplement checked against Caffeine (OTC drug), 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
Dyer's Broom monograph › Uses, safety, and every drug interaction in one place Caffeine (OTC drug) supplement interactions › Every supplement checked against Caffeine (OTC drug), 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 Dyer's Broom and Caffeine (OTC drug) Together: Common Questions

Can you take Dyer's Broom with Caffeine (OTC drug)?
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 Dyer's Broom and Caffeine (OTC drug) 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 Caffeine (OTC drug) and Dyer's Broom?

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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.