Drug & supplement interaction

Limonene + Fluoxetine

Fluoxetine brand names: Prozac, Sarafem.

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

Fluoxetine falls into 3 drug categories that Limonene can interact with; the most serious is rated moderate. There's preliminary evidence that limonene might be a substrate for cytochrome P450 2C19 (CYP2C19).

Read the full interaction report
SeverityModerate
LikelihoodPossible
Interactions3
EvidenceD
What do Severity, Likelihood & Evidence mean?
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Interaction report

Limonene and Fluoxetine

These two interact in 3 distinct ways. Each one is explained separately below.

Why Are There 3 Interactions?

Limonene interacts with whole categories of medication. Fluoxetine falls into 3 of those categories, so it can interact with Limonene in 3 different ways. We’ve listed each one below — your overall risk is driven by the most serious of them (Moderate).

Moderate

CYTOCHROME P450 2C19 (CYP2C19) INHIBITORS

1 of 3

Why this applies to Fluoxetine

Fluoxetine falls under CYTOCHROME P450 2C19 (CYP2C19) INHIBITORS — the group Limonene interacts with.

There's preliminary evidence that limonene might be a substrate for cytochrome P450 2C19 (CYP2C19). So far, this interaction has not been reported in humans. However, watch for an increase in the limonene levels when it is taken with drugs that inhibit CYP2C19. Some drugs that inhibit CYP2C19 include cimetidine (Tagamet), fluvoxamine (Luvox), omeprazole (Prilosec); ticlopidine (Ticlid), topiramate (Topamax), and others.
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 key thing to understand about this pairing: the interaction works in the other direction from what you might expect. Fluoxetine (Prozac) is one of the medications that blocks the liver enzyme CYP2C19, and early lab data suggests limonene is broken down by that same enzyme. So fluoxetine could slow the clearance of limonene, letting limonene build up a bit, not the other way around. Your fluoxetine levels and its effects aren't expected to change.

This is very preliminary, coming only from test-tube and animal work, and it hasn't been seen in real people. Everyday citrus and food amounts of limonene are very unlikely to matter. If you're using a concentrated limonene supplement, just check with your pharmacist first.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Crowell PL. Prevention and therapy of cancer by dietary monoterpenes. J Nutr 1999;129:775S-778S. PubMed
  2. Miyazawa M, Shindo M, Shimada T. Metabolism of (+)- and (-)-limonenes to respective carveols and perillyl alcohols by CYP2C9 and CYP2C19 in human liver microsomes. Drug Metab Dispos 2002;30:602-7. PubMed
Moderate

CYTOCHROME P450 2C9 (CYP2C9) INHIBITORS

2 of 3

Fluoxetine also falls under CYTOCHROME P450 2C9 (CYP2C9) INHIBITORS.

There's preliminary evidence that limonene might be a substrate for cytochrome P450 2C9 (CYP2C9). So far, this interaction has not been reported in humans. However, watch for side effects in patients taking limonene and CYP2C9 inhibitors. Some CYP2C9 inhibitors include amiodarone (Cordarone), fluconazole (Diflucan), lovastatin (Mevacor), paroxetine (Paxil), zafirlukast (Accolate), and many others.
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 key thing to understand: in this pairing, fluoxetine (Prozac) is the one doing the blocking, not limonene. Fluoxetine slows down a liver enzyme called CYP2C9, and early lab work suggests limonene may be broken down by that same enzyme. So in theory, fluoxetine could cause limonene to clear more slowly and hang around a bit longer in your body. This does not make your fluoxetine stronger or weaker.

The honest bottom line is that this is very weak evidence, based only on test tube and animal studies, and it has never actually been reported in people. Citrus in your food won't be an issue. If you're taking concentrated limonene capsules, just mention it to your pharmacist and watch for any unusual stomach upset. Don't change your fluoxetine.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Crowell PL. Prevention and therapy of cancer by dietary monoterpenes. J Nutr 1999;129:775S-778S. PubMed
  2. Miyazawa M, Shindo M, Shimada T. Metabolism of (+)- and (-)-limonenes to respective carveols and perillyl alcohols by CYP2C9 and CYP2C19 in human liver microsomes. Drug Metab Dispos 2002;30:602-7. PubMed
Moderate

CYTOCHROME P450 2C9 (CYP2C9) SUBSTRATES

3 of 3

Fluoxetine also falls under CYTOCHROME P450 2C9 (CYP2C9) SUBSTRATES.

There's preliminary evidence that limonene might be a substrate for cytochrome P450 2C9 (CYP2C9), as well causing its induction. So far, this interaction has not been reported in humans. However, watch for a decrease in the levels of drugs metabolized by CYP2C9 in patients taking limonene. Some drugs metabolized by CYP2C9 include nonsteroidal anti-inflammatory drugs (NSAIDs) such as diclofenac (Cataflam, Voltaren), ibuprofen (Motrin), meloxicam (Mobic), and piroxicam (Feldene); celecoxib (Celebrex); amitriptyline (Elavil); warfarin (Coumadin); glipizide (Glucotrol); losartan (Cozaar); and others.
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 gist for Prozac (fluoxetine). Limonene, the citrus-peel compound, may gently speed up a liver enzyme called CYP2C9, which is one of the pathways that helps clear certain medicines. If that enzyme works faster, a drug it handles could be broken down a bit quicker and lose some punch. For fluoxetine that could, in theory, mean your antidepressant works less well, with symptoms like low mood, anxiety, or irritability creeping back.

The important part: this is only suggested by lab and animal studies, not seen in actual people, and fluoxetine is mainly cleared by other enzymes (CYP2D6 and 2C19). So real-world risk looks low, and the small amount of limonene in citrus food won't matter. Before starting a concentrated limonene supplement, just check with your pharmacist or doctor.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Crowell PL. Prevention and therapy of cancer by dietary monoterpenes. J Nutr 1999;129:775S-778S. PubMed
  2. Miyazawa M, Shindo M, Shimada T. Metabolism of (+)- and (-)-limonenes to respective carveols and perillyl alcohols by CYP2C9 and CYP2C19 in human liver microsomes. Drug Metab Dispos 2002;30:602-7. 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

Limonene Also Interacts With Other Medications

Limonene has 229 moderate known drug interactions in our database — the Fluoxetine one above is among them. If you take anything else, check it against the full list below.

Moderate 229 No known interaction 2,601 (incl. Fluoxetine)
Taking anything else?

Check Another of Your Medications Against Limonene

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

From our Q&A

Questions About Limonene or Fluoxetine

These are real questions from readers, answered by the pharmacists at HelloPharmacist — written by a person, not generated from a database. Each one covers Limonene or Fluoxetine, not necessarily both, but if one is close to what you were about to ask it will usually go further than a database entry can:

Not quite your question? Ask our pharmacists directly — it is free, there is no account required, and answers usually come back within 24 hours.

Everything else you take

See Every Supplement That Interacts With Fluoxetine

This page covers Limonene only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Fluoxetine page lists 163 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), American Hellebore (major), Arsenic (major), Cesium (major) and Ephedra (major).

By severity: 8 major · 127 moderate · 28 minor.

From our pharmacist’s overview on the Fluoxetine page

“Grapefruit is the surprise at the top of fluoxetine's (Prozac) supplement list. In large amounts it can stretch the QT interval, the electrical pause between heartbeats, and fluoxetine, a widely prescribed antidepressant, can do the same, raising the odds of a dangerous rhythm.”

Reviewed by 2 · Jul 18, 2026

Open the Fluoxetine interaction page

One more smart check

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

We hold 89 real supplement products containing Limonene, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Limonene. Your product may carry other ingredients that interact with Fluoxetine too, on top of Limonene — 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 Limonene and Fluoxetine 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 Limonene
Top half

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

29 days ago today
Medication Fluoxetine
Top 5%

#65 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 Limonene

What is Limonene?

  • Heartburn and acid reflux
  • Digestive upset
  • Stress and mood support
  • Antioxidant support
  • General wellness

Limonene is a natural compound found in the peel of citrus fruits like oranges and lemons, and it is used as a flavoring agent and dietary supplement. People take it for heartburn, digestion, and general wellness, but solid human evidence is limited. It is generally well tolerated in food amounts, but talk with your pharmacist or doctor before using concentrated supplements.

Read the full Limonene monograph & all interactions
Medication

About Fluoxetine

What Is Fluoxetine Used For?

Brand names: Prozac, Sarafem

Fluoxetine treats several mental health conditions. Most fluoxetine products are labeled for major depressive disorder (MDD), obsessive compulsive disorder (OCD), bulimia nervosa (binge-eating and vomiting behaviors) and panic disorder, with or without agoraphobia (fear of open or crowded places).

Some uses are product-specific. Fluoxetine delayed-release capsules are labeled only for major depressive disorder. Prozac capsules and fluoxetine capsules are also labeled to be used together with olanzapine for depressive episodes linked to Bipolar I Disorder and for treatment resistant depression. Fluoxetine alone is not approved for those two uses.

See full Fluoxetine drug information
Keep checking

Other Drugs & Limonene

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

0Major
229Moderate
0Minor
2,600No known interaction
229 Moderate 2,600 No interaction
Moderate

229 interactions

Showing 60 of 229 moderate interactions — see all 229 on the Limonene page.

No interaction 2,600 drugs checked — show the list

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

Showing the 60 most looked-up of 2,600 medications checked with no known interaction — see the full Limonene list.

See the full Limonene interactions page
See every supplement checked against Fluoxetine, 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
Limonene monograph › Uses, safety, and every drug interaction in one place Fluoxetine supplement interactions › Every supplement checked against Fluoxetine, ranked by severity Fluoxetine 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 Limonene and Fluoxetine Together: Common Questions

Can you take Limonene with Fluoxetine?
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 3 interactions listed for Limonene and Fluoxetine?
Fluoxetine belongs to more than one drug category, and Limonene 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 Limonene and Fluoxetine 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 Fluoxetine and Limonene?

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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.