Drug & supplement interaction

Indole-3-carbinol + Simvastatin

Simvastatin brand name: Zocor.

No Known Interaction
Medically reviewed by · Updated July 2026 · Pair last verified Sep 20, 2026
The bottom line No known interaction

We found no known interaction between Indole-3-carbinol and Simvastatin in our sources. Absence of a documented interaction is not the same as proven safety, and does not guarantee one does not exist. Do not start, stop, or change a medication or supplement based on this page; confirm with your pharmacist or doctor first. Additionally, although there is no interaction, the two are separately associated with some of the same side effects, which would make a new symptom harder to attribute to one or the other.

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Interaction report

Indole-3-carbinol and Simvastatin

We checked these two against our interaction database. Here is what we found.

No Known Interaction Found

We did not find a documented interaction between Simvastatin and Indole-3-carbinol in our sources. This does not guarantee that the combination is completely free of risk — there is often limited research on supplements and herbal products, especially around drug interactions.

If you decide to take both, the practical routine is simple: add one new thing at a time and note the date you started it. If the combination is going to disagree with you, it usually shows in the first days to a couple of weeks — and a start date turns “I’ve been feeling off” into something a pharmacist can actually work with. Do not stop a prescribed medicine on your own.

Always talk with your pharmacist or doctor before making changes to your medications or supplements, particularly if you take several medications or have an ongoing health condition.

Indole-3-carbinol safety at a glance

Indole-3-carbinol overall Use caution Likely fine in food amounts, but supplement doses are less studied and should be used cautiously.
Pregnancy Avoid Not enough safety data and possible hormone effects, so concentrated supplements should be avoided.
Breastfeeding Avoid Safety has not been established, so supplement use is not recommended while breastfeeding.

Safety guidance is general; always confirm with your pharmacist or doctor for your situation.

Still wondering about combining Simvastatin and Indole-3-carbinol? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
How we checked

Why No Interaction Is Listed for Simvastatin

Interactions in our licensed database are recorded against drug classes, not just single drug names. Simvastatin is filed under 8 classifications — including hmg-coa reductase inhibitors ("statins"), organic anion-transporting polypeptide substrates (oatp), glucuronidated drugs. Indole-3-carbinol has documented interactions with 3 drug classes — the most serious being anticoagulant/antiplatelet drugs (moderate), cytochrome p450 1a2 (cyp1a2) substrates (moderate) and estrogens (moderate) — and none of Simvastatin’s classifications are among them.

Classification data comes from our licensed Natural Medicines dataset. A medication can belong to classes beyond those recorded there, so this describes how the check was run — it is not a safety guarantee.

Keep it in perspective

Indole-3-carbinol Does Interact With Other Medications

Indole-3-carbinol has 294 moderate known drug interactions in our database — Simvastatin isn’t one of them. If you take anything else, check it against the full list below.

Moderate 294 No known interaction 2,536 (incl. Simvastatin)
Taking anything else?

Check Another of Your Medications Against Indole-3-carbinol

Covers the 2,830 medications we’ve checked against Indole-3-carbinol. Pick one to open its full report.

What to actually watch for

No Interaction Found — But Data Suggests Indole-3-carbinol and Simvastatin May Share a Side Effect

This is not an interaction. Neither one changes how your body handles the other, and nothing here says they react together. What our sources do show is that each has separately been linked to the effects below — so taking both can make those effects more likely to turn up, and harder to pin on one or the other if they do.

  • Nausea reported in 5.3% of FDA reports for Simvastatin Additional detail

    Indole-3-carbinol

    “Indole-3-carbinol has been associated with reports of unsteadiness and imbalance, especially at higher doses. An adult male taking 400 mg twice daily for treatment of recurrent respiratory papillomatosis developed imbalance and tremor after 10 days of treatment. This resolved when the dose was halved.”

    Indole-3-carbinol · Natural Medicines adverse-effect record, reported in myasthenia gravis.

    2 sources cited
    1. 7172. 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. 93238. Anon. Indole-3-carbinol. Monograph. Alternative Medicine Review 2005;10(4):337-42.

    Simvastatin

    Listed in the ADVERSE REACTIONS section of the FDA label for Simvastatin, and in voluntary FDA adverse-event reports. Read the label on DailyMed ›

Reported for Indole-3-carbinol but not commonly for Simvastatin: unsteadiness, diarrhea, tremor or shakiness and a skin rash.

Effects for Simvastatin come from the ADVERSE REACTIONS section of its FDA label; effects for Indole-3-carbinol come from the Natural Medicines adverse-effect record, quoted above. Where a percentage is shown, it is the share of 261,345 voluntary FDA FAERS reports for Simvastatin that mention that effect — a reporting proportion, not an incidence rate and not evidence the drug caused it. Wording is matched across sources by our own clinical vocabulary, so treat this as a prompt to pay attention, not a diagnosis.

From our Q&A

Questions About Indole-3-carbinol or Simvastatin

These are real questions from readers, answered by the pharmacists at HelloPharmacist — written by a person, not generated from a database. Each one covers Indole-3-carbinol or Simvastatin, 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 Simvastatin

This page covers Indole-3-carbinol only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Simvastatin page lists 183 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Apple (major), Beer (major), Grapefruit (major) and Siberian Cocklebur (major).

By severity: 8 major · 139 moderate · 36 minor.

Open the Simvastatin interaction page

One more smart check

Taking Indole-3-carbinol as Part of a Dietary Supplement Product? Check It for Interactions

We hold 287 real supplement products containing Indole-3-carbinol, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Indole-3-carbinol. Even though Indole-3-carbinol itself has no known interaction with Simvastatin, another ingredient on your label might. Find your product and we’ll check every ingredient on its label:

How much people look this up

Where Indole-3-carbinol and Simvastatin 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 Indole-3-carbinol
Top 25%

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

29 days ago today
Medication Simvastatin
Top half

#786 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.

Where does our data come from?
  • Source: the Natural Medicines (TRC Healthcare) clinical database — the evidence-graded professional reference for herb & supplement interactions.
  • Citation library: 103,510 references behind our interaction content, 65,311 of them resolved to verified PubMed/DOI sources. See every Indole-3-carbinol reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 20, 2026. The Indole-3-carbinol and Simvastatin records this page draws on were last updated July 10, 2026.
  • What “no known interaction” means: no documented interaction in the sources above — not a guarantee of safety. Supplements are studied far less than prescription drugs, so we say exactly what the evidence supports, and nothing more.
Data structure & sourcing designed and verified by .
Supplement

About Indole-3-carbinol

What is Indole-3-carbinol?

  • Estrogen and hormone balance support
  • Breast and cervical health
  • Prostate health
  • Antioxidant and 'detox' support
  • General cancer-prevention interest

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 effects. Most human evidence is preliminary or comes from lab and animal studies, so it should not be relied on to prevent or treat any disease. Talk to your pharmacist or doctor before using it, and avoid it in pregnancy and breastfeeding.

Brassicaceae · Derived from glucosinolates found in cruciferous vegetables (broccoli, cabbage, Brussels sprouts, cauliflower) · Capsules, tablets, softgels; sometimes combined with or compared to diindolylmethane (DIM)

An interaction check asks whether these two react with each other — it does not ask whether Indole-3-carbinol is a good idea for someone in your situation. Here is what our Indole-3-carbinol record says about it on its own.

Indole-3-carbinol: dosing

There is no officially established or standardized dose for I3C. Different products and studies have used different amounts, and there is no agreed-upon 'best' dose.The safest approach is to follow the directions on the product label and not exceed them. They can help you decide whether I3C is appropriate for you.

From our Indole-3-carbinol monograph — the full record covers uses, side effects and every documented interaction.

Read the full Indole-3-carbinol monograph & all interactions
Medication

About Simvastatin

What Is Simvastatin Used For?

Brand name: Zocor

Simvastatin tablets are used alongside a cholesterol-lowering diet to treat high LDL cholesterol (bad cholesterol), high triglycerides, and certain inherited cholesterol disorders, including heterozygous familial hypercholesterolemia (HeFH) in adults and children aged 10 and older, and homozygous familial hypercholesterolemia (HoFH) in adults.

In adults who already have coronary heart disease, cerebrovascular disease, peripheral vascular disease, or diabetes and are at high risk for heart events, simvastatin is also used to reduce the risk of death from heart disease, non-fatal heart attack, stroke, and the need for procedures to open blocked arteries. Zocor is one brand-name product containing simvastatin and carries these same indications.

Most-Reported Side Effects for Simvastatin

From FAERS, the FDA’s public side-effect reporting system (263,006 reports, all brands). Reports are voluntary and are not proof the drug caused the effect.

Fatigue 14,524 reports
Nausea 14,119 reports
Dyspnea 13,226 reports
Diarrhea 12,591 reports
Dizziness 11,830 reports
See full Simvastatin drug information
Keep checking

Other Drugs & Indole-3-carbinol

Browse every other medication we’ve checked against Indole-3-carbinol — both the ones with a known interaction and the ones without. Select any drug for the full detail.

0Major
294Moderate
0Minor
2,535No known interaction
294 Moderate 2,535 No interaction
Moderate

294 interactions

Showing 60 of 294 moderate interactions — see all 294 on the Indole-3-carbinol page.

No interaction 2,535 drugs checked — show the list

We also checked Indole-3-carbinol against these medications and found no known interaction in our sources. Open any page to confirm.

Showing the 60 most looked-up of 2,535 medications checked with no known interaction — see the full Indole-3-carbinol list.

See the full Indole-3-carbinol interactions page
See every supplement checked against Simvastatin, ranked by severity
Evidence & sources

Indole-3-carbinol References

The 9 references that drive our Indole-3-carbinol monograph and interaction data, from the evidence-graded Natural Medicines (TRC Healthcare) database. Citations with a link open the study on PubMed or the publisher’s site.

  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

Medication overviews come from MedlinePlus (NIH); supplement label data from the NIH Dietary Supplement Label Database. Content is written and reviewed by licensed HelloPharmacist pharmacists — see our data sources and editorial standards.

Pharmacist Counseling Corner

Taking Indole-3-carbinol and Simvastatin Together: Common Questions

Is it safe to take Indole-3-carbinol with Simvastatin?
We do not list a known interaction between Indole-3-carbinol and Simvastatin. That does not guarantee the combination is risk-free, so confirm with your pharmacist or doctor — especially if you take other medications or have a health condition.
Do Indole-3-carbinol and Simvastatin have any of the same side effects?
Yes — our sources link each of them separately to one of the same effects. That is not an interaction: neither changes how your body handles the other. It does mean that if one of those effects turns up, it can be harder to tell which one is behind it. They are listed on this page with the source behind each.
How was the Indole-3-carbinol and Simvastatin combination checked?
Interactions in our licensed database are recorded against drug classes. Simvastatin is filed under 8 classifications, and Indole-3-carbinol has documented interactions with 3 drug classes — none of Simvastatin's classifications are among them. A medication can belong to classes beyond those recorded in our dataset, so this describes how the check was run rather than guaranteeing safety.
Does Indole-3-carbinol interact with any other medications?
Yes. Indole-3-carbinol has 294 documented drug interactions in our database — Simvastatin is simply not one of them. If you take anything else, it is worth checking each one; they are all listed on this page.
Does Simvastatin interact with any supplements?
Yes. Simvastatin has documented interactions with 183 supplements in our database — Indole-3-carbinol is not one of them. The Simvastatin interaction page linked on this page lists every one, ranked by severity.

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

Where next

Keep Exploring

Indole-3-carbinol monograph Uses, safety profile, and every drug interaction in one place Simvastatin drug information The full plain-English guide to this medication Simvastatin supplement interactions Every supplement checked against Simvastatin, ranked by severity Supplement interaction checker Check any supplement or product against your medications Browse medications A–Z Every drug we’ve checked against herbs & supplements References The 9 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Simvastatin and Indole-3-carbinol?

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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.