Major interaction on record — check this product against your medications before combining. Check your meds →
Dietary supplement

Grapefruit Seed 500 mg Ingredients & Drug Interactions

by Bronson

Grapefruit Seed 500 mg label
See full label image
Capsule Category: Botanical
Most serious interaction: Major
Clinical methodology reviewed by · Updated Sep 16, 2026 · Label data from the NIH DSLD
What is this page for?

First and foremost: checking Grapefruit Seed 500 mg against your medications. The heart of this page is the interaction checker and the full interaction report — how this product’s ingredients may interact with prescription and over-the-counter medicines you may be taking.

Around that, we add a pharmacist’s high-level view of the product as a whole — what’s inside, the evidence for its stated use, how transparent the label is, and what safety data exists — so you can see the full picture in one place. It’s educational information from our licensed clinical databases and the clinical staff at HelloPharmacist — not medical advice — and we don’t sell or endorse products. Our editorial policy

The interaction bottom line Most serious interaction: Major

Grapefruit Seed 500 mg is a dietary supplement by Bronson with 1 active ingredient. Its ingredients are commonly taken for source of vitamin c, digestive complaints, antimicrobial (seed extract).Based on those ingredients, 990 medications have a known interaction with it, the most serious rated major. The ingredients most likely to interact are Grapefruit, Powder. Use the checker below to test your specific medication, or read the full HelloPharmacist Interaction Report.

Jump to a section

Check Your Meds Against Grapefruit Seed 500 mg by Bronson

Ask about any prescription or over-the-counter medication and we check it for interactions with Grapefruit Seed 500 mg by Bronson — and tell you which ingredient is responsible.

Pharmacist-reviewed data Checks every ingredient Answer in seconds
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HelloPharmacist Scorecard of Grapefruit Seed 500 mg by Bronson

Our pharmacy team’s full take, with four database checks built into the cards below — a summary of what is known, not a grade of the product itself.

From our pharmacy team — supplement deep dive

Generated from HelloPharmacist’s pharmacist-curated databases and editorial rules · Last generated Jul 11, 2026

What’s inside

Full disclosure
Ingredient Transparency · database check
Full

Every active ingredient lists its own amount on the label.

Why this rating?
  • The label discloses an exact amount for 1 of its 1 active ingredient.
  • “Grapefruit, Powder” is listed as a grouped ingredient — the label gives one combined amount (500 mg) without saying how much of each component you get.

This product contains one active ingredient: grapefruit seed extract at 500 mg per capsule. The remaining ingredients are inactive — microcrystalline cellulose, modified cellulose, magnesium stearate, and silicon dioxide — which are fillers and binders that give the capsule its form.

Does it work?

Insufficient evidence
Evidence for Intended Use · database check
By FDA rules, dietary supplements can’t claim to treat, cure, or prevent disease — so labels speak in careful marketing language. We discern each product’s intended use from its name, label claims, and label statements, then grade the clinical evidence for that use. How these ratings are computed
Insufficient

There isn't enough reliable clinical evidence to rate this product's ingredients for its stated purpose.

Why this rating?
  • The label markets this product for: supports immune health and gastrointestinal tract.
  • We looked for evidence on: Upper respiratory tract infection (URTI), Pharyngitis, Intestinal parasite infection, Vaginal candidiasis, Gingivitis, Immune support — and 2 related terms.
  • The closest evidence on file: Grapefruit is rated "Insufficient Reliable Evidence To Rate" for Upper respiratory tract infection (URTI) (Natural Medicines).
  • Also on file: Grapefruit is rated "Insufficient Reliable Evidence To Rate" for Gingivitis, Intestinal parasite infection, Pharyngitis, Vaginal candidiasis.

The evidence for grapefruit seed extract is not established in the data we hold. Effectiveness ratings for acne, asthma, atherosclerosis, headache, upper respiratory tract infection, and depression all come back as insufficient reliable evidence to rate.

If you're considering this supplement for any of those reasons, talk with your pharmacist about what the current research actually supports.

The evidence, ingredient by ingredient Grapefruit

How safe is it?

Well-documented data
Safety Information · database check
Well characterized

Adverse-effect, pregnancy, and general safety data are on file for most of these ingredients.

Why this rating?
  • We hold adverse-effect (side-effect) data for 1 of the 1 matched ingredient.
  • Pregnancy & breastfeeding safety ratings cover 1 of 1.
  • General safety write-ups exist for 1 of 1.
  • Remember: this measures how much safety information exists. Thin data is not the same as being safe.

Grapefruit and grapefruit juice are generally well tolerated when eaten as food. However, concentrated supplements like this one haven't been as well studied for safety.

Serious side effects are rare but have been reported — allergic reactions in sensitive individuals, and at high doses, heart rhythm problems (arrhythmias), QT prolongation (a change in heart electrical activity), and mineral imbalances. Preliminary research suggests that people who consume large amounts of grapefruit daily may have a higher breast cancer risk, possibly because grapefruit can raise estrogen levels in the body; the evidence isn't final, but it's something to discuss with your doctor if you're at risk or have a history of hormone-sensitive cancer.

Side effects, ingredient by ingredient Grapefruit

Meds to double-check

Major interaction found
Known Interaction Concern · database check
Major identified

At least one ingredient has a documented Major-severity interaction. Check your medications for a personalized result.

Why this rating?
  • 1 of the 1 matched ingredient can interact with medications — Grapefruit.
  • The most serious interaction on file is rated Major.
  • Some involve high-stakes drug classes: anticoagulant / antiplatelet drugs; immunosuppressants / transplant drugs; heart-rhythm medications.
  • For scale: 991 individual medications appear in the full list. A big number alone doesn't make a product dangerous — what matters is whether YOUR medication is on it, so run yours through the interaction checker on this page.

Do not use this product without checking Major interactions first: heart rhythm medications like amiodarone, motion sickness patches (scopolamine), immunosuppressants like cyclosporine, anxiety medications (buspirone), cough suppressants (dextromethorphan), blood pressure drugs (celiprolol), and cancer drugs (etoposide). Grapefruit seed extract can drastically raise or lower blood levels of these drugs.

Run your medications through the checker on this page before you begin.

Check your own medication Run your meds through the checker above

The bottom line

Scorecard at a glanceFully disclosed formula with insufficient evidence for its stated purpose. Major medication interactions have been identified, and safety information is well characterized.

This supplement is a strong medication interactor — if you take anything for your heart, anxiety, cough, or any drug processed through your liver, you need to check it first with your pharmacist or doctor. The effectiveness for common uses isn't well established.

Even though grapefruit is a common food, concentrated extracts like this warrant a conversation with your healthcare provider before you start.

Educational only — not medical advice; always confirm with your pharmacist. Our editorial policy · How we use AI

Assessment coverage: 1 of 1 active ingredient matched to our full ingredient reviews (monographs). Based on the product label dated Aug 22, 2024.

This Scorecard evaluates available label information, ingredient evidence, and known medication-safety considerations. It does not independently verify product identity, purity, potency, contamination, or manufacturing quality. How these ratings are computed

At a glance

General information

Key facts about Grapefruit Seed 500 mg, straight from the product label.

Brand Bronson
Barcode (UPC) 716563312077
Net contents 120 Vegetarian Capsule(s)
Market status On market
Date entered into DSLD Aug 22, 2024
DSLD ID 317318
Product type Botanical
Supplement form Capsule
Dietary claims / uses All Other, Structure/Function
Intended target group(s) Adult (18 - 50 Years), Gluten Free
From the label
Everything in this section is reproduced from the manufacturer’s own product label — it’s the label speaking, not HelloPharmacist. We show it so you can see exactly what the maker states; we don’t verify or endorse those statements.

Supplement Facts

The label details for Grapefruit Seed 500 mg by Bronson, sourced from the NIH Dietary Supplement Label Database.

Supplement Facts

Daily Value (DV) Target Group(s):
Adults and children 4 or more years of age
Minimum serving Sizes:
2 Capsule(s)
Maximum serving Sizes:
2 Capsule(s)
Servings per container
60
UPC/BARCODE
716563312077
IngredientAmount% DV
Grapefruit seed extract125 mg--
Grapefruit, Powder500 mg--

Other ingredients: Microcrystalline Cellulose, Modified Cellulose, Magnesium Stearate, Silicon Dioxide

Tap any ingredient to jump to its full detail below.

Label statements
These statements are the manufacturer’s wording, reproduced from the product label — the label is saying it, not HelloPharmacist. We don’t verify or endorse them.
Brand IP Statement(s)

Bronson Nutrition+ Since 1960

Formula

Grapefruit Seed 500 mg per serving Citrus paradisi

Formulation

Supports immune health Maintains a healthy gastrointestinal tract

GMO-free Gluten-free Soy-free

Lab Tested Made from High Quality Ingredients 365 days 100% money back guaranteed

FDA Statement of Identity

Dietary Supplement

Suggested/Recommended/Usage/Directions

Directions: As a dietary supplement for adults, take 2 capsules daily, preferably with a meal or as directed by a healthcare professional.

Precautions

Warning: Consult a healthcare professional before taking this product if you are pregnant or nursing.

Do not use if seal under cap is broken or missing.

Keep out of reach of children.

Storage

Store at room temperature.

FDA Disclaimer Statement

These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure or prevent any disease.

Seals/Symbols

GMP Good Manufacturing Practice

General Statements

Nutrition questions or comments? [email protected] Call 1-800-235-3200 Mon. - Fri. 7 AM - 6 PM MST Sat. 8 AM - 4:30 PM MST

Is this label outdated? Report a formula or label change and our pharmacy team will review it.

See for yourself

Grapefruit Seed 500 mg by Bronson label

The label scan from the NIH Dietary Supplement Label Database. Tap to enlarge.

Grapefruit Seed 500 mg label

Label images are published by the NIH Dietary Supplement Label Database for the version of this product on file. Always read your actual product label.

View the full label (PDF)
What’s inside

The Ingredients in Grapefruit Seed 500 mg by Bronson

This is the 1 active ingredient this product is made of. Select it to open its full monograph.

Serving size2 Capsule(s) Dosage formCapsule Servings per container60 Amounts shown are per serving.

Grapefruit, Powder

Interacts with
990 drugs
500 mg per serving

Grapefruit is a nutritious citrus fruit rich in vitamin C and other nutrients, and it is generally safe to eat. However, grapefruit is famous for seri...

Grapefruit, Powder monograph & interactions

Other (inactive) ingredients: Microcrystalline Cellulose, Modified Cellulose, Magnesium Stearate, Silicon Dioxide. These complete the product’s ingredient list but are not active constituents.

Interaction report

Grapefruit Seed 500 mg by Bronson Drug Interactions

Want to check YOUR meds against Grapefruit Seed 500 mg?

Ask about interactions with your drugs in plain English — “Can I take it with lisinopril?” — and we find you the answer in seconds, ingredient by ingredient.

 Go to the checker
990Drugs
776 Major 151 Moderate 63 Minor

Ingredients driving the most interactions

Grapefruit, Powder 990

Individual Drug Interactions

The ingredients in Grapefruit Seed 500 mg interact with 990 drugs. Click any drug to see the details.

1 of the 1 ingredient in Grapefruit Seed 500 mg interact with drugs. Each result below shows which ingredient is responsible. Grapefruit, Powder

Each ingredient & the kinds of drugs it affects

For each ingredient in Grapefruit Seed 500 mg with known interactions, here are the types of medications it can affect. Open any type for the detail — or search your exact drug in the checker above.

Grapefruit, Powder62 drug types · 990 drugs

Amiodarone (Cordarone)

Grapefruit juice can increase blood levels of amiodarone, potentially increasing the effects and adverse effects of amiodarone.
Clinical research shows that grapefruit juice inhibits metabolism and increases absorption of amiodarone. Grapefruit juice increases amiodarone plasma levels by 50% and peak concentration by 84%.

Likelihood Probable Evidence B
Artemether (Artenam, Paluther)

Grapefruit juice can increase blood levels of oral artemether, potentially increasing the effects and adverse effects of artemether.
Clinical research shows that grapefruit juice increases the levels of oral artemether by 90% to 250% in healthy males.

Likelihood Likely Evidence B
Benzodiazepines

Grapefruit juice might increase blood levels of some oral benzodiazepines, potentially increasing the effects and adverse effects of these drugs.
Clinical research shows that grapefruit juice can increase plasma triazolam concentrations. Repeated consumption of grapefruit juice greatly increases triazolam concentrations and prolongs the half-life, probably due to inhibition of cytochrome P450 3A4 (CYP3A4). Some studies show that grapefruit juice, particularly when taken in large quantities, reduces the clearance and increases the maximum blood levels, area under the plasma concentration curve (AUC), and duration of effect of midazolam. However, there is no effect on intravenous midazolam. Grapefruit juice has also been shown to increase the maximum blood levels and duration of effect of diazepam, but the clinical significance of this is not known. This interaction does not appear to occur with alprazolam.

Likelihood Likely Evidence B
Buspirone (Buspar)

Grapefruit juice can increase blood levels of buspirone, potentially increasing the effects and adverse effects of buspirone.
Clinical research shows that grapefruit juice increases absorption and plasma concentrations of buspirone.

Likelihood Likely Evidence B
Calcium Channel Blockers

Grapefruit juice can increase blood levels of oral calcium channel blockers, potentially increasing the effects and adverse effects of these drugs.
Clinical research shows that grapefruit juice increases absorption and plasma concentrations of amlodipine, nifedipine, nisoldipine, verapamil, felodipine, nimodipine, nicardipine, diltiazem, pranidipine, nitrendipine, and manidipine, This interaction is likely the result of the inhibition of intestinal metabolism of these drugs by CYP3A4, although some research suggests grapefruit may alter plasma drug levels by reducing the rate of gastric emptying. Consuming grapefruit juice 1 liter daily increases steady state concentrations of verapamil by as much as 50%. However, some references dispute the clinical relevance of the interactions with amlodipine, diltiazem, and verapamil. Other research in healthy individuals suggests plasma levels of felodipine and nifedipine are not affected when given intravenously. There is considerable interindividual variability in the effect of grapefruit juice on drug metabolism, which might account for inconsistent study results. In healthy older adults, the hemodynamic response to felodipine plus grapefruit juice might be influenced by altered autonomic regulation. In older healthy adults, a single dose of grapefruit juice and felodipine enhanced the blood pressure-lowering effects of felodipine. However, after a week of grapefruit juice and felodipine (steady state), the hypotensive activity was reduced, possibly due to compensatory tachycardia. Research indicates it is necessary to withhold grapefruit juice for as long as 3 days to avoid interactions with felodipine and nisoldipine.

Likelihood Likely Evidence B
Carbamazepine (Tegretol)

Grapefruit juice can increase blood levels of carbamazepine, potentially increasing the effects and adverse effects of carbamazepine.
Clinical research shows that grapefruit juice increases absorption and plasma concentrations of carbamazepine.

Likelihood Likely Evidence B
Carvedilol (Coreg)

Grapefruit juice can increase blood levels of carvedilol, potentially increasing the effects and adverse effects of carvedilol.
Clinical research shows that grapefruit juice increases the bioavailability of a single dose of carvedilol by 16%.

Likelihood Likely Evidence B
Celiprolol (Celicard)

Grapefruit juice can decrease blood levels of celiprolol, potentially decreasing the clinical effects of celiprolol.
In human research, taking grapefruit juice within two hours of celiprolol appears to decrease absorption and blood levels of celiprolol by approximately 85%. This interaction is due to grapefruit-induced inhibition of organic anion transporting polypeptide (OATP). Grapefruit juice is thought to affect OATP for only a short time. Therefore, separating drug administration and consumption of grapefruit by at least 4 hours is likely to prevent this interaction.

Likelihood Probable Evidence B
Cisapride (Propulsid)

Grapefruit juice can increase blood levels of cisapride, potentially increasing the effects and adverse effects of cisapride.
Clinical research shows that grapefruit juice increases the absorption and plasma concentrations of cisapride. According to the cisapride prescribing information, grapefruit juice is contraindicated in patients taking cisapride.

Likelihood Likely Evidence B
Clomipramine (Anafranil)

Theoretically, grapefruit juice might increase blood levels of clomipramine, potentially increasing the effects and adverse effects of clomipramine.
Case reports have shown that clomipramine trough levels increase significantly after the addition of grapefruit juice to the therapeutic regimen.

Likelihood Probable Evidence D
Clopidogrel (Plavix)

Grapefruit juice can decrease blood levels of the active metabolite of clopidogrel, thereby decreasing the antiplatelet effect of clopidogrel.
Clopidogrel is an antiplatelet prodrug that is metabolized primarily by cytochrome P450 2C19 (CYP2C19) to form the active metabolite. A small clinical study shows that taking grapefruit juice with clopidogrel decreases plasma levels of the active metabolite by more than 80% and impairs the antiplatelet effect of clopidogrel. This effect is possibly due to grapefruit-induced inhibition of CYP2C19.

Likelihood Probable Evidence B
Cyclosporine (Neoral, Sandimmune)

Grapefruit juice can increase blood levels of oral cyclosporine, potentially increasing the effects and adverse effects of cyclosporine.
Clinical research shows that grapefruit juice increases the absorption and plasma concentrations of cyclosporine. The mechanism of action is unclear. However, there is no effect on intravenous cyclosporine.

Likelihood Likely Evidence B
Cytochrome P450 3A4 (Cyp3A4) Substrates

Grapefruit juice can increase levels of drugs metabolized by CYP3A4.
Clinical research shows that grapefruit juice can inhibit CYP3A4 metabolism of drugs, causing increased drug levels and potentially increasing the risk of adverse effects. When taken orally, effects of grapefruit juice on CYP3A4 levels appear to last at least 48 hours. Grapefruit's ability to inhibit CYP3A4 has even been harnessed to intentionally increase levels of venetoclax, which is metabolized by CYP3A4, in an elderly patient with acute myeloid leukemia who could not afford full dose venetoclax. The lower dose of venetoclax in combination with grapefruit juice resulted in serum levels of venetoclax in the therapeutic reference range of full dose venetoclax and positive treatment outcomes for the patient.
Professional consensus recommends the consideration of patient age, existing medical conditions, additional medications, and the potential for additive adverse effects when evaluating the risks of concomitant use of grapefruit juice with any medication metabolized by CYP3A4. While all patients are at risk for interactions with grapefruit juice consumption, patients older than 70 years of age and those taking multiple medications are at the greatest risk for a serious or fatal interaction with grapefruit juice.

Likelihood Likely Evidence B
Dextromethorphan (Robitussin Dm, Others)

Grapefruit juice can increase blood levels of dextromethorphan, potentially increasing the effects and adverse effects of dextromethorphan.
Clinical research shows that grapefruit juice can inhibit cytochrome P450 3A4 (CYP3A4) metabolism, causing increased dextromethorphan levels.

Likelihood Probable Evidence B
Estrogens

Grapefruit juice can increase blood levels of estrogens, potentially increasing the effects and adverse effects of estrogens.
Clinical research shows that grapefruit increases the levels of endogenous and exogenous estrogens by inhibiting cytochrome P450 3A4 (CYP3A4) enzymes. Grapefruit juice increases exogenously administered 17-beta-estradiol by about 20% in females without ovaries and ethinyl-estradiol in healthy females.

Likelihood Probable Evidence B
Etoposide (Vepesid)

Grapefruit juice can decrease blood levels of etoposide, potentially decreasing the clinical effects of etoposide.
Clinical research shows that grapefruit juice decreases the absorption and plasma concentrations of etoposide. There is some evidence that grapefruit juice co-administered with oral etoposide can reduce levels of etoposide by about 26%. Grapefruit juice seems to inhibit organic anion transporting polypeptide (OATP), which is a drug transporter in the gut, liver, and kidney. Grapefruit juice is thought to affect OATP for only a short time. Therefore, separating drug administration and consumption of grapefruit by at least 4 hours is likely to prevent this interaction.

Likelihood Probable Evidence B
Halofantrine

Grapefruit juice can increase blood levels of halofantrine, potentially increasing the effects and adverse effects of halofantrine.
Clinical research shows that grapefruit juice inhibits cytochrome P450 3A4 (CYP3A4) metabolism, which increases halofantrine levels and peak concentration, as well as a marker of ventricular tachyarrhythmia potential.

Likelihood Probable Evidence B
Hmg-Coa Reductase Inhibitors ("Statins")

Grapefruit juice can increase blood levels of statins that are metabolized by cytochrome P450 3A4 (CYP3A4), potentially increasing the effects and adverse effects of these statins. Additionally, grapefruit juice might interfere with the bioavailability of statins that are substrates of organic anion transporting polypeptides (OATP).
Clinical research shows that grapefruit juice inhibits metabolism and increases absorption and plasma concentrations of statins that are metabolized by CYP3A4. These include lovastatin, simvastatin, and atorvastatin. Keep in mind that there is considerable variability in the effect of grapefruit juice on drug metabolism, so individual patient response is difficult to predict.
Some statins, including pravastatin, fluvastatin, pitavastatin, and rosuvastatin, are not metabolized by CYP3A4. However, grapefruit juice might still affect the bioavailability of these statins. These statins are substrates of OATP. Grapefruit juice can inhibit OATP. Therefore, grapefruit juice may reduce the bioavailability or increase drug levels of these statins depending on the type of OATP. However, grapefruit juice affects OATP for only a short time. Therefore, separating drug administration by at least 4 hours is likely to avoid this interaction.

Likelihood Likely Evidence B
Methadone (Dolophine)

Grapefruit juice can increase blood levels of methadone, potentially increasing the effects and adverse effects of methadone.
Clinical research shows that grapefruit juice inhibits the metabolism of methadone, increasing methadone levels and peak concentrations. In one case, a 51-year-old male taking methadone 90 mg daily and no other medications was found unresponsive. The patient reported drinking grapefruit juice 500 mL daily for 3 days prior to the event. Methadone is a substrate of cytochrome P450 3A4 (CYP3A4), and grapefruit juice-induced inhibition of CYP3A4 is the likely cause of this interaction.

Likelihood Probable Evidence B
Methylprednisolone

Grapefruit juice can increase blood levels of methylprednisolone, potentially increasing the effects and adverse effects of methylprednisolone.
Clinical research shows that grapefruit juice can increase the plasma concentration of orally administered methylprednisolone. Grapefruit juice 200 mL three times daily given with methylprednisolone 16 mg increased methylprednisolone half-life by 35%, peak plasma concentration by 27%, and total area under the curve by 75%.

Likelihood Likely Evidence B
Organic Anion-Transporting Polypeptide Substrates (Oatp)

Grapefruit juice can decrease levels of drugs that are substrates of OATP.
In vitro and clinical research show that consuming grapefruit juice inhibits OATP, which reduces the bioavailability of oral drugs that are substrates of OATP. Various clinical studies have shown reduced absorption of OATP substrates when taken with grapefruit, including fexofenadine, acebutolol, aliskiren, celiprolol, levothyroxine, nadolol, and pitavastatin. Grapefruit juice is thought to affect OATP for only a short time. Therefore, separating drug administration and consumption of grapefruit by at least 4 hours is likely to prevent this interaction.

Likelihood Likely Evidence B
Praziquantel (Biltricide)

Grapefruit juice can increase blood levels of praziquantel, potentially increasing the effects and adverse effects of praziquantel.
Clinical research shows that grapefruit juice can inhibit cytochrome P450 3A4 (CYP3A4) metabolism of praziquantel. Plasma concentrations of praziquantel can increase by as much as 160% when administered with 250 mL of commercially available grapefruit juice.

Likelihood Probable Evidence B
Qt Interval-Prolonging Drugs

Grapefruit or grapefruit juice, especially if consumed in large amounts, can cause additive QT interval prolongation when taken with QT interval-prolonging drugs, potentially increasing the risk of ventricular arrhythmias.
Clinical research in healthy volunteers shows that drinking 6 liters of grapefruit juice over 6 hours prolonged the QTc by a peak amount of 14 milliseconds (ms). This prolongation was similar to the QT prolongation caused by the drug moxifloxacin. In individuals with long QT syndrome, a smaller dose of grapefruit juice, 1.5 liters, resulted in a greater peak QTc prolongation of about 30 ms. The effect of smaller quantities of grapefruit juice on the QT interval is unclear.

Likelihood Probable Evidence B
Quetiapine (Seroquel)

Grapefruit juice may increase blood levels of quetiapine, increasing the effects and adverse effects of quetiapine.
Quetiapine is metabolized by cytochrome P450 3A4 (CYP3A4). Grapefruit can inhibit CYP3A4. In one case report, a healthy 28-year-old female with bipolar disorder stabilized on quetiapine 800 mg daily presented with quetiapine toxicity considered to be related to consuming a gallon of grapefruit juice over the past 24 hours.

Likelihood Probable Evidence B
Quinidine

Grapefruit juice can alter blood levels of quinidine, potentially increasing or decreasing the clinical effects of quinidine.
Clinical research shows that grapefruit juice decreases quinidine absorption, clearance, and metabolism, and prolongs the half-life by about 20%.

Likelihood Probable Evidence B
Grapefruit, Powder full monograph & all 62 interactions
The maker

Brand information

Manufacturer and brand details for Grapefruit Seed 500 mg, from the product label.

Bronson

Name
Bronson Laboratories
Street Address
70 Commerce Drive
City
Hauppauge
State
NY
ZipCode
11788
Phone Number
1-800-235-3200
Web Address
BronsonVitamins.com
Pharmacist Counseling Corner

Grapefruit Seed 500 mg by Bronson: Common Questions

Does Grapefruit Seed 500 mg by Bronson interact with any medications?
Yes. Based on its ingredients, Grapefruit Seed 500 mg has a known interaction with 990 medications, including 776 rated major. Use the checker to see how it interacts with a specific drug.
How can one product interact with so many drugs?
Grapefruit Seed 500 mg contains a single active ingredient, and that one ingredient can interact with many different medications on its own. We check it against each medication and show the mechanism responsible.
Where does this information come from?
The product label data comes from the NIH Dietary Supplement Label Database (DSLD); the interaction data is built on the Natural Medicines database and reviewed by HelloPharmacist pharmacists.
Is grapefruit seed extract safe to take with my medicines?
Not without checking first. This supplement interacts with hundreds of medications — it can raise or lower drug levels in your blood, which may cause side effects or make your medicine less effective. Use the search tool on this page to look up your exact medications before starting it.
Does this work for anything?
We don't have reliable evidence that grapefruit seed extract is effective for acne, asthma, atherosclerosis, headache, upper respiratory infections, or depression. If you're thinking about it for one of those reasons, talk with your pharmacist about what's actually been proven to help.
Is grapefruit seed extract the same as eating grapefruit?
Not quite. Eating grapefruit as food is generally fine. But this is a concentrated extract, which hasn't been studied as thoroughly for safety. The interaction risks are real with both, though — if you take any medications, your pharmacist should know if you're consuming grapefruit or grapefruit products regularly.
What side effects should I watch for?
Serious side effects are rare, but allergic reactions can happen in people who are sensitive. At higher doses, heart rhythm changes (arrhythmias) and electrolyte imbalances have been reported. If you notice heart palpitations, shortness of breath, or difficulty breathing, stop and call your doctor.
Is it safe if I'm pregnant or breastfeeding?
We don't have safety data on file for grapefruit seed extract in pregnancy or lactation. Talk with your doctor or pharmacist before using it if you're pregnant, planning to become pregnant, or breastfeeding — they can give you personalized advice.

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

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Label information is sourced from the NIH Dietary Supplement Label Database and reflects the product version on file; always read your actual product label. This page is for education only and is not a substitute for professional medical advice. Confirm with your pharmacist or doctor before combining supplements and medications.

Grapefruit Seed 500 mg label
Go deeper

The Full Monographs Behind Grapefruit Seed 500 mg’s Ingredients

Every ingredient we hold a full HelloPharmacist monograph for — uses, evidence, safety, and the complete interaction list.

Herb & supplement monograph

Grapefruit

Interacts with 990 drugs

Grapefruit is a nutritious citrus fruit rich in vitamin C and other nutrients, and it is generally safe to eat. However, grapefruit is famous for serious interactions with many prescription...

Read the full Grapefruit monograph →
Sources

Sources & How We Checked

Grapefruit Seed 500 mg's label data comes from the NIH Dietary Supplement Label Database; the ingredient interaction data is from the Natural Medicines database, reviewed by our pharmacists.

Content is written and reviewed by licensed HelloPharmacist pharmacists. See our data sources and editorial standards for how this information is built and checked.

The 157 references behind this product’s interaction data

Every citation that drives the interaction findings for this product’s ingredients, from the evidence-graded Natural Medicines (TRC Healthcare) database. Open an ingredient to browse its citations — links open the study on PubMed or the publisher’s site.

Grapefruit 157 references
  1. Penzak SR, Gubbins PO, Gurley BJ, et al. Grapefruit juice decreases the systemic availability of itraconazole capsules in healthy volunteers. Ther Drug Monit 1999;21:304-9. PubMed
  2. Ioannides-Demos LL, Christophidis N, et al. Dosing implications of a clinical interaction between grapefruit juice and cyclosporine and metabolite concentrations in patients with autoimmune diseases. J Rheumatol 1997;24:49-54.
  3. Josefsson M, Zackrisson AL, Ahlner J. Effect of grapefruit juice on the pharmacokinetics of amlodipine in healthy volunteers. Eur J Clin Pharmacol 1996;51:189-93. PubMed
  4. Garg SK, Kumar N, Bhargava VK, Prabhakar SK. Effect of grapefruit juice on carbamazepine bioavailability in patients with epilepsy. Clin Pharmacol Ther 1998;64:286-8. PubMed
  5. Weber A, Jager R, Borner A, et al. Can grapefruit juice influence ethinylestradiol bioavailability? Contraception 1996;53:41-7.
  6. Schubert W, Cullberg G, Edgar B, Hedner T. Inhibition of 17 beta-estradiol metabolism by grapefruit juice in ovariectomized women. Maturitas 1994;20:155-63.
  7. Kantola T, Kivisto KT, Neuvonen PJ, et al. Grapefruit juice greatly increases serum concentrations of lovastatin and lovastatin acid. Clin Pharmacol Ther 1998 63:397-402. PubMed
  8. Bailey DG, Spence JD, Munoz C, Arnold JM. Interaction of citrus juices with felodipine and nifedipine. Lancet 1991;337:268-9. PubMed
  9. Bailey DG, Arnold JM, Strong HA, et al. Effect of grapefruit juice and naringin on nisoldipine pharmacokinetics. Clin Pharmacol Ther 1993;54:589-94. PubMed
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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

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