Drug & supplement interaction

Caffeic Acid + Levodopa

Levodopa brand names: Larodopa, Inbrija.

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

Caffeic Acid has a minor interaction with Levodopa. Theoretically, caffeic acid might increase the levels and clinical effects of levodopa.

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

Caffeic Acid and Levodopa

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

Minor

LEVODOPA

Theoretically, caffeic acid might increase the levels and clinical effects of levodopa.
In an animal model, caffeic acid 10 mg/kg seems to significantly decrease conversion of levodopa to 3-O-methyldopa by about 22%. Caffeic acid also decreased the maximum concentration (Cmax) of 3-O-methyldopa by about 31%. There is speculation that this interaction could be beneficial for Parkinson disease patients. However, the clinical significance of this potential interaction in humans is not known.
Severity Minor 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 gist for caffeic acid and your levodopa (Inbrija or the levodopa in Sinemet, Rytary, and Duopa). In animal studies, caffeic acid slowed down one of the pathways that breaks levodopa into a less useful byproduct called 3-O-methyldopa. In theory, that could leave a little more levodopa available to reach the brain, which might slightly boost its effect on movement, stiffness, and tremor.

I want to be straight with you, though: this has only been seen in lab and animal research, not in people, so we really don't know if it matters at human supplement doses. The everyday caffeic acid in coffee, fruits, and vegetables is very unlikely to change anything. Before adding a concentrated supplement, check with your pharmacist or doctor first.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Wang LH, Hsu KY, Uang YS, et al. Caffeic acid improves the bioavailability of L-dopa in rabbit plasma. Phytother Res 2010;24:852-8.

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

Caffeic Acid Also Interacts With Other Medications

Caffeic Acid has 177 moderate, 4 minor known drug interactions in our database — the Levodopa one above is one of them. If you take anything else, check it against the full list below.

Moderate 177 Minor 4 No known interaction 2,649 (incl. Levodopa)
Taking anything else?

Check Another of Your Medications Against Caffeic Acid

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

Everything else you take

See Every Supplement That Interacts With Levodopa

This page covers Caffeic Acid only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Levodopa page lists 41 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Branched-chain Amino Acids (bcaa) (major), Cowhage (major), Indian Snakeroot (major) and Magnesium (major).

By severity: 8 major · 22 moderate · 11 minor.

From our pharmacist’s overview on the Levodopa page

“Parkinson symptoms return fast when levodopa (Larodopa, Inbrija) stops reaching the brain, and most of the 41 supplements on this page can make that happen, so treat these combinations with genuine care. Protein and amino acid supplements compete with levodopa for transport into the brain, while everyday minerals like magnesium and iro…”

Reviewed by 2 · Jul 18, 2026

Open the Levodopa interaction page

One more smart check

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

We hold 20 real supplement products containing Caffeic Acid, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Caffeic Acid. Your product may carry other ingredients that interact with Levodopa too, on top of Caffeic Acid — 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 Caffeic Acid and Levodopa 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 Caffeic Acid
Top half

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

29 days ago today
Medication Levodopa
Top 10%

#165 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 Caffeic Acid

What is Caffeic Acid?

  • Antioxidant support
  • General anti-inflammatory use
  • Skin and sun protection (topical)
  • Immune support
  • Cancer-prevention interest (research stage)

Caffeic acid is a natural plant compound found in coffee, many fruits, vegetables, and herbs, and it is studied mainly for its antioxidant and anti-inflammatory properties. Most evidence comes from laboratory and animal research, so its benefits in people are not yet proven. If you want to take it as a supplement, talk with your pharmacist or doctor first.

Read the full Caffeic Acid monograph & all interactions
Medication

About Levodopa Oral Inhalation

What Is Levodopa Oral Inhalation Used For?

Brand names: Larodopa, Inbrija

Inbrija is used to treat OFF episodes in adults with Parkinson's disease. An OFF episode is when your regular oral carbidopa/levodopa medication temporarily stops working well enough, causing Parkinson's symptoms — such as stiffness, slowness, or tremor — to return.

Inbrija is used as needed when OFF symptoms start to come back. It is not a replacement for your regular oral carbidopa/levodopa; it works alongside it.

See full Levodopa Oral Inhalation drug information
Keep checking

Other Drugs & Caffeic Acid

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

0Major
177Moderate
4Minor
2,648No known interaction
177 Moderate 4 Minor 2,648 No interaction
Moderate

177 interactions

Showing 60 of 177 moderate interactions — see all 177 on the Caffeic Acid page.

Minor

4 interactions

No interaction 2,648 drugs checked — show the list

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

Showing the 60 most looked-up of 2,648 medications checked with no known interaction — see the full Caffeic Acid list.

See the full Caffeic Acid interactions page
See every supplement checked against Levodopa, 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
Caffeic Acid monograph › Uses, safety, and every drug interaction in one place Levodopa supplement interactions › Every supplement checked against Levodopa, ranked by severity Levodopa Oral Inhalation drug information › The full plain-English guide to this medication 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 Caffeic Acid and Levodopa Together: Common Questions

Can you take Caffeic Acid with Levodopa?
There is only a minor interaction, which is usually not serious. Read the full details on this page and confirm with your pharmacist before combining them.
How serious is the Caffeic Acid and Levodopa interaction?
We rate it Minor. This interaction is generally not clinically significant, but it remains worth noting and discussing with your pharmacist.

Written and reviewed by the HelloPharmacist editorial staff. Our editorial policy

Still Have a Question About Levodopa and Caffeic Acid?

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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.