Drug & supplement interaction

Quercetin + Propranolol

Propranolol brand names: Inderal LA, Inderal, Angilol, Syprol, Inderal Injection, and others.

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

Propranolol falls into 2 drug categories that Quercetin can interact with; the most serious is rated moderate. Theoretically, taking quercetin with antihypertensive drugs might increase the risk of hypotension.

Read the full interaction report
SeverityModerate
LikelihoodPossible
Interactions2
EvidenceB
What do Severity, Likelihood & Evidence mean?
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Interaction report

Quercetin and Propranolol

These two interact in 2 distinct ways. Each one is explained separately below.

Why Are There 2 Interactions?

Quercetin interacts with whole categories of medication. Propranolol falls into 2 of those categories, so it can interact with Quercetin in 2 different ways. We’ve listed each one below — your overall risk is driven by the most serious of them (Moderate).

Moderate

ANTIHYPERTENSIVE DRUGS

1 of 2

Why this applies to Propranolol

Propranolol falls under ANTIHYPERTENSIVE DRUGS — the group Quercetin interacts with.

Theoretically, taking quercetin with antihypertensive drugs might increase the risk of hypotension.

Quercetin can modestly decrease blood pressure in people with mild hypertension. Theoretically, it might have additive blood pressure lowering effects when used with antihypertensive drugs.
Severity Moderate Likelihood Possible Evidence B

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 propranolol: this isn't really about how your body breaks the drug down. Instead, it's about effects stacking up. Propranolol already lowers your blood pressure and slows your heart rate, and quercetin in concentrated supplement doses can nudge blood pressure down a little too. Put them together and you could see a bit more lowering than expected.

In plain terms, that might mean feeling dizzy or lightheaded, tired, or woozy when you stand up quickly. The evidence here is fairly weak and the effect is usually mild, and quercetin from everyday foods like apples and onions isn't likely to cause trouble. Still, if you're considering a high-dose supplement, run it by your pharmacist or doctor first.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Edwards RL, Lyon T, Litwin SE, et al. Quercetin reduces blood pressure in hypertensive subjects. J Nutr 2007;137:2405-11.
  2. Larson A, Witman MA, Guo Y, et al. Acute, quercetin-induced reductions in blood pressure in hypertensive individuals are not secondary to lower plasma angiotensin-converting enzyme activity or endothelin-1: nitric oxide. Nutr Res. 2012;32(8):557-64. PubMed
Moderate

CYTOCHROME P450 2D6 (CYP2D6) SUBSTRATES

2 of 2

Propranolol also falls under CYTOCHROME P450 2D6 (CYP2D6) SUBSTRATES.

Theoretically, concomitant use might increase the levels and adverse effects of CYP2D6 substrates.

In vitro research show that quercetin inhibits CYP2D6. This effect has not been reported 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 simple version. Your body relies partly on an enzyme called CYP2D6 to break down propranolol and clear it out. Quercetin, in lab studies, can slow that enzyme down. If that happened in real life, propranolol could build up a bit higher than usual, which might nudge its effects up too. With propranolol that could mean a slower heart rate, lower blood pressure, more tiredness, lightheadedness, or cold hands and feet.

The important part: this is only seen in test-tube research, not in people, so it's theoretical. Everyday food amounts of quercetin are very unlikely to matter. If you're thinking about a high-dose supplement, just run it by your pharmacist or doctor first so they can keep an eye on your pulse and blood pressure.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Obach RS. Inhibition of human cytochrome P450 enzymes by constituents of St. John's wort, an herbal preparation used in the treatment of depression. J Pharmacol Exp Ther 2000;294:88-95. DOI
  2. DiCenzo R, Frerichs V, Larppanichpoonphol P, et al. Effect of quercetin on the plasma and intracellular concentrations of saquinavir in healthy adults. Pharmacotherapy 2006;26:1255-61. 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

Quercetin Also Interacts With Other Medications

Quercetin has 1,168 moderate known drug interactions in our database — the Propranolol one above is among them. If you take anything else, check it against the full list below.

Moderate 1,168 No known interaction 1,662 (incl. Propranolol)
Taking anything else?

Check Another of Your Medications Against Quercetin

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

Everything else you take

See Every Supplement That Interacts With Propranolol

This page covers Quercetin only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Propranolol page lists 236 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), American Hellebore (major), American Mistletoe (major), Indian Snakeroot (major) and Tyramine (major).

By severity: 5 major · 194 moderate · 37 minor.

From our pharmacist’s overview on the Propranolol page

“Propranolol (Inderal) slows the heart and lowers blood pressure, which is exactly why its 236-ingredient interaction list deserves genuine care. Five entries rate major, and those are the ones to understand first.”

Reviewed by 2 · Jul 18, 2026

Open the Propranolol interaction page

One more smart check

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

We hold 4,589 real supplement products containing Quercetin, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Quercetin. Your product may carry other ingredients that interact with Propranolol too, on top of Quercetin — 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 Quercetin and Propranolol 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 Quercetin
Top 5%

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

29 days ago today
Medication Propranolol
Top 10

#8 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 Quercetin

What is Quercetin?

Quercetin
  • Seasonal allergies
  • Antioxidant support
  • Heart and blood pressure health
  • Anti-inflammatory support
  • Immune support
  • Exercise recovery

Quercetin is a plant flavonoid with antioxidant and anti-inflammatory properties found in many common foods and sold as a supplement. While early research is interesting for allergies, blood pressure, and inflammation, strong human evidence is limited for most uses. It is generally well tolerated in food amounts, but talk to your pharmacist or doctor before taking high-dose supplements.

Read the full Quercetin monograph & all interactions
Medication

About Propranolol (Cardiovascular)

What Is Propranolol (Cardiovascular) Used For?

Brand names: Inderal LA, Inderal, Angilol, Syprol, Inderal Injection, Half-Inderal LA, Bedranol SR, Half Beta Prograne, Beta Prograne, Lopranol LA, Slo-Pro, InnoPran XL

This intravenous (IV) form of propranolol is used in hospital or clinical settings to treat dangerous heart rhythm problems. It is generally reserved for life-threatening arrhythmias (abnormal heart rhythms) or those that occur during anesthesia.

Specific conditions it treats include fast heart rates coming from the upper chambers of the heart (supraventricular tachycardia), certain arrhythmias caused by digitalis toxicity, dangerous ventricular rhythms that haven't responded to other treatments, and fast heart rates caused by excess adrenaline-like substances during surgery.

See full Propranolol (Cardiovascular) drug information
Keep checking

Other Drugs & Quercetin

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

0Major
1,168Moderate
0Minor
1,661No known interaction
1,168 Moderate 1,661 No interaction
Moderate

1,168 interactions

Showing 60 of 1,168 moderate interactions — see all 1,168 on the Quercetin page.

No interaction 1,661 drugs checked — show the list

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

Showing the 60 most looked-up of 1,661 medications checked with no known interaction — see the full Quercetin list.

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

Can you take Quercetin with Propranolol?
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 2 interactions listed for Quercetin and Propranolol?
Propranolol belongs to more than one drug category, and Quercetin 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 Quercetin and Propranolol 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 Propranolol and Quercetin?

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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.