Drug & supplement interaction

Kudzu + Caffeine (OTC drug)

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

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

Kudzu has a moderate interaction with Caffeine (OTC drug). Theoretically, taking kudzu with caffeine might increase levels of caffeine.

Read the full interaction report
SeverityModerate
LikelihoodProbable
EvidenceD
What do Severity, Likelihood & Evidence mean?
Know someone taking this? Share
Facebook Post Reddit Email
On this page
Interaction report

Kudzu and Caffeine (OTC drug)

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

Moderate

CAFFEINE

Theoretically, taking kudzu with caffeine might increase levels of caffeine.
In healthy males injected with the kudzu constituent puerarin, caffeine clearance and metabolism is inhibited. This effect has been attributed to inhibition of cytochrome P450 1A2 (CYP1A2) enzyme, which is involved in caffeine metabolism. It is unclear if taking kudzu orally would have this same effect.
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

Here's the gist: your body relies on a liver enzyme called CYP1A2 to break down caffeine. Kudzu (specifically a compound in it called puerarin) may slow that enzyme down. If caffeine clears more slowly, it can hang around longer and feel stronger. With an OTC caffeine pill like Vivarin, that could mean more jitteriness, a racing or pounding heart, trouble sleeping, or feeling anxious and shaky.

The honest part: this is theoretical. The clearest evidence comes from kudzu being injected, not swallowed, so we don't really know if oral kudzu does the same thing. If you take both, just be aware your usual caffeine might hit harder. Check with your pharmacist or doctor before combining them.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Zheng, J., Chen, B., Jiang, B., Zeng, L., Tang, Z. R., Fan, L., and Zhou, H. H. The effects of puerarin on CYP2D6 and CYP1A2 activities in vivo. Arch Pharm Res 2010;33(2):243-246. 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

Kudzu Also Interacts With Other Medications

Kudzu has 511 moderate, 72 minor 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 511 Minor 72 No known interaction 2,247 (incl. Caffeine (OTC drug))
Taking anything else?

Check Another of Your Medications Against Kudzu

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

Everything else you take

See Every Supplement That Interacts With Caffeine (OTC drug)

This page covers Kudzu 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 Kudzu as Part of a Dietary Supplement Product? Check It for Interactions

We hold 536 real supplement products containing Kudzu, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Kudzu. Your product may carry other ingredients that interact with Caffeine (OTC drug) too, on top of Kudzu — 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 Kudzu 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 Kudzu
Top 25%

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

29 days ago today
Medication Caffeine (OTC drug)
Top 10%

#154 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 Kudzu

What is Kudzu?

Kudzu
  • Alcohol cravings and reduction
  • Menopausal symptoms
  • Heart and blood vessel health
  • Hangover relief
  • Traditional Chinese medicine (Ge Gen)

Kudzu is a fast-growing vine whose root has long been used in traditional Chinese medicine and is now studied mostly for reducing alcohol intake. Early research is promising for cutting back on drinking, but evidence for most other uses is weak. Talk with your pharmacist or doctor before trying it, and avoid it during pregnancy and breastfeeding.

Read the full Kudzu monograph & all interactions
Keep checking

Other Drugs & Kudzu

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

0Major
511Moderate
72Minor
2,246No known interaction
511 Moderate 72 Minor 2,246 No interaction
Moderate

511 interactions

Showing 60 of 511 moderate interactions — see all 511 on the Kudzu page.

Minor

72 interactions

Showing 60 of 72 minor interactions — see all 72 on the Kudzu page.

No interaction 2,246 drugs checked — show the list

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

Showing the 60 most looked-up of 2,246 medications checked with no known interaction — see the full Kudzu list.

See the full Kudzu 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
Kudzu 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 Kudzu and Caffeine (OTC drug) Together: Common Questions

Can you take Kudzu 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 Kudzu 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 Kudzu?

Our pharmacists answer your medication & supplement questions — free.

Ask a pharmacist

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.