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Dietary supplement

Indole-3-Carbinol Ingredients & Drug Interactions

by Nature's Sunshine

Indole-3-Carbinol label
See full label image
Capsule Category: Other Combinations
Most serious interaction: Moderate
Clinical methodology reviewed by · Updated Sep 9, 2026 · Label data from the NIH DSLD
What is this page for?

First and foremost: checking Indole-3-Carbinol 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: Moderate

Indole-3-Carbinol is a dietary supplement by Nature's Sunshine with 2 active ingredients. Its ingredients are commonly taken for estrogen and hormone balance support, breast and cervical health, prostate health.Based on those ingredients, 295 medications have a known interaction with it, the most serious rated moderate. The ingredients most likely to interact are Indole-3-Carbinol, Broccoli. Use the checker below to test your specific medication, or read the full HelloPharmacist Interaction Report.

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Check Your Meds Against Indole-3-Carbinol by Nature's Sunshine

Ask about any prescription or over-the-counter medication and we check it for interactions with Indole-3-Carbinol by Nature's Sunshine — and tell you which ingredient is responsible.

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HelloPharmacist Scorecard of Indole-3-Carbinol by Nature's Sunshine

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

Low disclosure
Ingredient Transparency · database check
Low

Most active ingredients don't disclose an individual amount — you can't tell how much of each you're getting.

Why this rating?
  • The label discloses an exact amount for 0 of its 2 active ingredients.
  • “Proprietary Blend” is a proprietary blend — the label gives one combined amount (960 mg) without saying how much of each component you get.

This product contains 2 active ingredients: indole-3-carbinol and broccoli, delivered in a proprietary blend. Indole-3-carbinol is a compound extracted from cruciferous vegetables like broccoli and cabbage; broccoli here appears as a concentrated ingredient as well.

The capsule itself and the other materials inside — vegetable magnesium stearate and silicon dioxide — are inactive ingredients that help hold the formula together.

Does it work?

Not established
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
Not established

The graded evidence we hold for these ingredients covers different conditions than the ones this product is marketed for, so there's no established rating for its stated use.

Why this rating?
  • The label markets this product for: female health and hormone balance support.
  • We looked for evidence on: Breast cancer, Cervical dysplasia, Ovarian cancer, Prostate cancer, estrogen metabolism, hormonal health.
  • The closest evidence on file: Indole-3-carbinol is rated "Insufficient Reliable Evidence To Rate" for Breast cancer (Natural Medicines).
  • Also on file: Indole-3-carbinol is rated "Insufficient Reliable Evidence To Rate" for Cervical dysplasia, Ovarian cancer.
  • Also on file: Broccoli is rated "Insufficient Reliable Evidence To Rate" for Breast cancer, Prostate cancer.

The evidence we hold doesn't establish that this product works for the conditions listed. For indole-3-carbinol, the data shows insufficient evidence to rate it for breast cancer, colorectal cancer, cervical dysplasia, liver disease, and fibromyalgia.

Broccoli has possibly effective evidence for colorectal cancer, but for breast cancer, bladder cancer, gastric cancer, and fibromyalgia, the evidence is also insufficient. In short, we don't have solid data showing this supplement prevents or treats any of these conditions.

The evidence, ingredient by ingredient Indole-3-carbinol Broccoli

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 2 of the 2 matched ingredients.
  • Pregnancy & breastfeeding safety ratings cover 2 of 2.
  • General safety write-ups exist for 2 of 2.
  • Remember: this measures how much safety information exists. Thin data is not the same as being safe.

Indole-3-carbinol is generally well tolerated when taken orally, though a small number of people have reported diarrhea, nausea, rash, tremor, and unsteadiness — especially at higher doses. One case showed that imbalance and tremor resolved when the dose was cut in half.

Broccoli as food is safe for most people, but the safety data on concentrated broccoli supplements is less established. The safety notes on file advise caution with concentrated supplements and recommend avoiding them unless your doctor approves.

Regarding pregnancy: there isn't enough data to know whether this product is safe in pregnancy — talk with your doctor or pharmacist for personalized advice. The data advises against using indole-3-carbinol in concentrated supplement form while breastfeeding.

Side effects, ingredient by ingredient Indole-3-carbinol Broccoli

Meds to double-check

Moderate interaction found
Known Interaction Concern · database check
Moderate identified

The most serious documented interaction for these ingredients is Moderate. Check your medications for a personalized result.

Why this rating?
  • 2 of the 2 matched ingredients can interact with medications — Indole-3-carbinol, Broccoli.
  • The most serious interaction on file is rated Moderate.
  • Some involve high-stakes drug classes: anticoagulant / antiplatelet drugs.
  • For scale: 295 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.

Before taking this product, check with your pharmacist if you're on blood thinners or antiplatelet drugs — indole-3-carbinol may increase bleeding risk. Also double-check any medications metabolized by your liver enzymes CYP1A2 or CYP2A6, as both ingredients in this product can lower their blood levels and reduce how well they work.

If you take estrogen therapy or hormonal birth control, indole-3-carbinol may interfere with its effectiveness.

Check your own medication Run your meds through the checker above

The bottom line

Scorecard at a glanceFormula with limited ingredient disclosure with no established evidence rating for its marketed use. Moderate medication interactions have been identified, and safety information is well characterized.

This product combines two ingredients that both speed up how your liver breaks down medications, which can make those drugs less effective — and one of them may also raise bleeding risk if you're on blood thinners or interfere with hormone therapy. If you take any prescription medication, run it through the checker below before you start.

A conversation with your pharmacist is especially important before taking this product.

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

Assessment coverage: 2 of 2 active ingredients matched to our full ingredient reviews (monographs). Based on the product label dated Oct 24, 2022.

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 Indole-3-Carbinol, straight from the product label.

Brand Nature's Sunshine
Barcode (UPC) 099904015067
Net contents 60 Capsule(s)
Market status On market
Date entered into DSLD Oct 24, 2022
DSLD ID 278127
Product type Other Combinations
Supplement form Capsule
Dietary claims / uses All Other, Structure/Function
Intended target group(s) Adult (18 - 50 Years)
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 Indole-3-Carbinol by Nature's Sunshine, 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
30
UPC/BARCODE
099904015067
IngredientAmount% DV
Proprietary Blend960 mg--
Indole-3-Carbinol0 NP--
Broccoli0 NP--

Other ingredients: Capsule, Vegetable 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.
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.

General Statements

Bottle made from 100% post consumer recycled material. We are committed to you and our planet. Scan to learn more.

New look! Same great product

Formula

This formula supplies indole-3-carbinol in a proprietary blend of broccoli flowers, a cruciferous vegetable. Indole-3-carbinol is an active compound in cruciferous vegetables, which supports cell health by supporting immune health, balancing hormone metabolism and inducing detoxifying enzymes.

Female health formula

Precautions

This bottle was sealed for your protection. Do not use if inner seal is missing or damaged.

Formulation

Promotes optimal hormone balance

Guaranteed pure

FDA Statement of Identity

Dietary Supplement

Brand IP Statement(s)

Natures Sunshine Herbal experts since 1972

Suggested/Recommended/Usage/Directions

Recommended Use: Take 2 capsules daily with a meal.

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

See for yourself

Indole-3-Carbinol by Nature's Sunshine label

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

Indole-3-Carbinol 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 Indole-3-Carbinol by Nature's Sunshine

These are the 2 active ingredients this product is made of. Select any to open its full monograph.

Serving size2 Capsule(s) Dosage formCapsule Servings per container30 Amounts shown are per serving.

Most supplement products combine several ingredients, and a medication can interact with the product through any one of them. Each ingredient below shows whether it has known drug interactions.

Proprietary Blend

960 mg per serving

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

Interaction report

Indole-3-Carbinol by Nature's Sunshine Drug Interactions

Want to check YOUR meds against Indole-3-Carbinol?

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
295Drugs
295 Moderate

Ingredients driving the most interactions

Indole-3-Carbinol 294
Broccoli 187

Individual Drug Interactions

The ingredients in Indole-3-Carbinol interact with 295 drugs. Click any drug to see the details.

2 of the 2 ingredients in Indole-3-Carbinol interact with drugs. Each result below shows which ingredient is responsible. Indole-3-Carbinol Broccoli

Each ingredient & the kinds of drugs it affects

For each ingredient in Indole-3-Carbinol with known interactions, here are the types of medications they can affect. Open any type for the detail — or search your exact drug in the checker above.

Indole-3-Carbinol3 drug types · 294 drugs

Anticoagulant/Antiplatelet Drugs

Theoretically, indole-3-carbinol might increase the risk of bleeding when used with antiplatelet or anticoagulant drugs.
In vitro research shows that indole-3-carbinol inhibits platelet aggregation.

Likelihood Possible Evidence D
Cytochrome P450 1A2 (Cyp1A2) Substrates

Theoretically, indole-3-carbinol might increase the metabolism of CYP1A2 substrates and lower serum concentrations.
Animal research shows that indole-3-carbinol induces CYP1A2 enzymes.

Likelihood Possible Evidence D
Estrogens

Indole-3-carbinol might interfere with the effects of estrogen therapy.
Preliminary clinical and in vitro evidence shows that indole-3-carbinol has antiestrogenic activity.

Likelihood Possible Evidence D
Indole-3-Carbinol full monograph & interactions

Broccoli2 drug types · 187 drugs

Cytochrome P450 1A2 (Cyp1A2) Substrates

Theoretically, broccoli might reduce the levels and effects of drugs metabolized by CYP1A2.
Pharmacokinetic research in humans shows that eating 500 grams of fresh broccoli daily for 6-12 days can increase CYP1A2 activity by 10% to 200%. Induction of CYP1A2 activity by broccoli is attributed to its glucosinolate constituents.

Likelihood Possible Evidence B
Cytochrome P450 2A6 (Cyp2A6) Substrates

Theoretically, broccoli might reduce the levels and effects of drugs metabolized by CYP2A6.
Pharmacokinetic research in humans shows that eating 500 grams of broccoli daily for 6 days increases CYP2A6 activity by 135% to 550%. Induction of CYP2A6 activity is attributed to its glucosinolate constituents.

Likelihood Possible Evidence B
Broccoli full monograph & interactions
The maker

Brand information

Manufacturer and brand details for Indole-3-Carbinol, from the product label.

Nature's Sunshine

See all Nature's Sunshine products
Name
Nature's Sunshine Products, Inc.
City
Spanish Fork
State
UT
ZipCode
84660
Phone Number
1-800-223-8225
Web Address
www.naturessunshine.com
Pharmacist Counseling Corner

Indole-3-Carbinol by Nature's Sunshine: Common Questions

Does Indole-3-Carbinol by Nature's Sunshine interact with any medications?
Yes. Based on its ingredients, Indole-3-Carbinol has a known interaction with 295 medications. Use the checker to see how it interacts with a specific drug.
How can one product interact with so many drugs?
Indole-3-Carbinol contains 2 active ingredients, and an interaction can come from any of them. We check every ingredient, combine the results into one list per medication, and show which ingredient and mechanism is 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.
What is indole-3-carbinol and where does it come from?
Indole-3-carbinol is a compound naturally found in cruciferous vegetables like broccoli, cabbage, and cauliflower. This product extracts and concentrates it into supplement form, which means you're getting a much higher dose than you'd eat in food.
Could this affect my birth control or hormone replacement therapy?
Yes — indole-3-carbinol may interfere with how well estrogen therapy works, including hormonal birth control. Talk with your doctor or pharmacist before adding this product if you're on hormone-based medications.
What side effects might I experience?
Most common are diarrhea, nausea, rash, tremor, and unsteadiness. Higher doses are more likely to cause problems, especially balance issues. If you notice tremor or imbalance, stop and talk with your pharmacist right away.
Is it safe to use while breastfeeding?
No — the safety data advises against taking concentrated indole-3-carbinol supplements while breastfeeding. Talk with your doctor or pharmacist before considering this product.
Is there proof this product prevents or treats cancer?
The evidence we hold doesn't establish that it works for breast, colorectal, or cervical cancer or for any of the other conditions listed on the label. The data is insufficient to rate it for these uses.
Is it safe if I eat broccoli in my diet?
Broccoli as food in normal amounts is safe for most people. This supplement, though, is a concentrated extract — the safety of that form is less well studied, and the safety notes recommend caution or doctor approval before use.

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.

Indole-3-Carbinol label
Go deeper

The Full Monographs Behind Indole-3-Carbinol’s Ingredients

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

Herb & supplement monograph

Indole-3-carbinol

Interacts with 294 drugs

Indole-3-carbinol (I3C) is a compound formed when you eat cruciferous vegetables like broccoli and cabbage, and it is sold as a supplement mainly for hormone-related and cell-protective effe...

Read the full Indole-3-carbinol monograph → Herb & supplement monograph

Broccoli

Interacts with 187 drugs

Broccoli is a nutritious cruciferous vegetable rich in fiber, vitamins, and plant compounds like sulforaphane that have drawn scientific interest for health benefits. Eating broccoli as food...

Read the full Broccoli monograph →
Sources

Sources & How We Checked

Indole-3-Carbinol'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 14 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.

Indole-3-carbinol 9 references
  1. Rosen CA, Woodson GE, Thompson JW, et al. Preliminary results of the use of indole-3-carbinol for recurrent respiratory papillomatosis. Otolaryngol Head Neck Surg 1998;118:810-5. PubMed
  2. Bell MC, Crowley-Nowick P, Bradlow HL, et al. Placebo-controlled trial of indole-3-carbinol in the treatment of CIN. Gynecol Oncol 2000;78:123-9. PubMed
  3. He YH, Friesen MD, Ruch RJ, Schut HA. Indole-3-carbinol as a chemopreventive agent in 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) carcinogenesis: inhibition of PhIP-DNA adduct formation, acceleration of PhIP metabolism, and induction of cytoch
  4. Kim, Y. S. and Milner, J. A. Targets for indole-3-carbinol in cancer prevention. J.Nutr.Biochem. 2005;16(2):65-73. PubMed
  5. Anon. Indole-3-carbinol. Monograph. Alternative Medicine Review 2005;10(4):337-42.
  6. McAlindon TE, Gulin J, Chen T, et al. Indole-3-carbinol in women with SLE: effect on estrogen metabolism and disease activity. Lupus 2001;10:779-83. PubMed
  7. Reed GA, Peterson KS, Smith HJ, et al. A phase I study of indole-3-carbinol in women: tolerability and effects. Cancer Epidemiol Biomarkers Prev 2005;14:1953-60. PubMed
  8. Bradlow HL, Michnovicz JJ, Halper M, et al. Long-term responses of women to indole-3-carbinol or a high fiber diet. Cancer Epidemiol Biomarkers Prev 1994;3:591-5.
  9. Paliwal P, Chauhan G, Gautam D, Dash D, Patne SCU, Krishnamurthy S. Indole-3-carbinol improves neurobehavioral symptoms in a cerebral ischemic stroke model. Naunyn Schmiedebergs Arch Pharmacol. 2018;391(6):613-625. PubMed

See these in context on the Indole-3-carbinol monograph →

Broccoli 5 references
  1. Kristal AR, Lampe JW. Brassica vegetables and prostate cancer risk: a review of the epidemiological evidence. Nutr Cancer 2002;42:1-9. PubMed
  2. Chakrabarti A, Prais L, Foulds IS. Allergic contact dermatitis to broccoli. Br J Dermatol 2003;148:172-3. PubMed
  3. Hakooz, N. and Hamdan, I. Effects of dietary broccoli on human in vivo caffeine metabolism: a pilot study on a group of Jordanian volunteers. Curr Drug Metab 2007;8(1):9-15. PubMed
  4. Kall MA, Vang O, Clausen J. Effects of dietary broccoli on human drug metabolising activity. Cancer Lett. 1997;114(1-2):169-70. PubMed
  5. Bauman JE, Hsu CH, Centuori S, et al. Randomized Crossover Trial Evaluating Detoxification of Tobacco Carcinogens by Broccoli Seed and Sprout Extract in Current Smokers. Cancers (Basel). 2022;14(9):2129. Published 2022 Apr 24. PubMed

See these in context on the Broccoli monograph →

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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