Interactions on record — worth a quick check against your medications. Check your meds →
Dietary supplement

I3C Plus Ingredients & Drug Interactions

by Health Products Distributors

I3C Plus label
See full label image
Capsule Category: Non-nutrient/non-botanical
Most serious interaction: Moderate
Clinical methodology reviewed by · Updated Sep 16, 2026 · Label data from the NIH DSLD
What is this page for?

First and foremost: checking I3C Plus 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

I3C Plus is a dietary supplement by Health Products Distributors with 4 active ingredients. Its ingredients are commonly taken for common cold and immune support, antioxidant support, skin health and collagen formation.Based on those ingredients, 446 medications have a known interaction with it, the most serious rated moderate. The ingredients most likely to interact are Indole-3-Carbinol, Diindolymethane, Vitamin C. Use the checker below to test your specific medication, or read the full HelloPharmacist Interaction Report.

Jump to a section

Check Your Meds Against I3C Plus by Health Products Distributors

Ask about any prescription or over-the-counter medication and we check it for interactions with I3C Plus by Health Products Distributors — and tell you which ingredient is responsible.

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HelloPharmacist Scorecard of I3C Plus by Health Products Distributors

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 Aug 6, 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 4 of its 4 active ingredients.
  • No proprietary blends here — you can verify the dose of every single component.

I3C Plus contains four active ingredients. Vitamin C is a well-known antioxidant and immune supporter.

Betaine HCl is a form of betaine bound to hydrochloric acid, intended to support stomach acid production. Indole-3-carbinol and diindolylmethane are both compounds derived from cruciferous vegetables like broccoli and cabbage, included for their potential effects on hormone metabolism and cell function.

The capsule also contains inactive ingredients: gelatin, microcrystalline cellulose, silica, and magnesium trisilicate, which are fillers and binders.

Does it work?

Strong 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

This product doesn't appear to be marketed for a specific use, so we graded its ingredients' overall clinical evidence instead.

Strong

Strong clinical evidence supports its ingredients for:

Why this rating?
  • We looked at the product name, claims, and label statements and couldn't find a stated purpose to grade.
  • Since the label doesn't commit to one use, we graded the ingredients' overall clinical evidence instead.
  • On file: Vitamin C deficiency — rated "Effective" (Vitamin C) (Natural Medicines).
  • On file: Hypercholesterolemia — rated "Possibly Effective" (Vitamin C) (Natural Medicines).
  • On file: Anemia of chronic disease — rated "Possibly Effective" (Vitamin C) (Natural Medicines).
  • On file: Atrial fibrillation — rated "Possibly Effective" (Vitamin C) (Natural Medicines).
  • On file: Laser skin resurfacing — rated "Possibly Effective" (Vitamin C) (Natural Medicines).

The evidence for this product's effectiveness is mixed and limited. Vitamin C is effective for vitamin C deficiency and possibly effective for anemia of chronic disease, atrial fibrillation, cataracts, and exercise-induced respiratory infections.

However, for the other three active ingredients—betaine HCl, indole-3-carbinol, and diindolylmethane—the data we hold shows insufficient reliable evidence to rate their effectiveness for the conditions they're studied for, including digestive issues, cancer prevention, and hormonal health. If you're considering this product for a specific health goal, talk with your doctor or pharmacist about whether the evidence supports it for your situation.

The evidence, ingredient by ingredient Vitamin C Betaine Hydrochloride Indole-3-carbinol Diindolylmethane

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 4 of the 4 matched ingredients.
  • Pregnancy & breastfeeding safety ratings cover 4 of 4.
  • General safety write-ups exist for 4 of 4.
  • Remember: this measures how much safety information exists. Thin data is not the same as being safe.

Vitamin C is generally well tolerated at normal dietary and supplement doses, though very high doses can cause abdominal cramps, heartburn, osmotic diarrhea, nausea, vomiting, and headache—especially above 2 grams daily. Rare serious effects from high-dose intravenous use include kidney problems.

Betaine HCl may irritate the stomach and is not appropriate for people with ulcers, gastritis, or acid reflux; it could cause heartburn. Indole-3-carbinol is well tolerated but has been associated with diarrhea, nausea, rash, and in some cases tremor and unsteadiness, especially at higher doses.

Diindolylmethane is generally well tolerated short-term but may cause diarrhea, gas, headache, nausea, rash, and vomiting; one rare case of a rash with eosinophilia and systemic symptoms (DRESS) has been reported.

Side effects, ingredient by ingredient Vitamin C Betaine Hydrochloride Indole-3-carbinol Diindolylmethane

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?
  • 4 of the 4 matched ingredients can interact with medications — Betaine Hydrochloride, Vitamin C, Indole-3-carbinol, Diindolylmethane.
  • The most serious interaction on file is rated Moderate.
  • Some involve high-stakes drug classes: anticoagulant / antiplatelet drugs; cancer treatments.
  • For scale: 446 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 I3C Plus, check with your doctor or pharmacist if you take: estrogens or hormone replacement therapy (moderate risk from vitamin C, indole-3-carbinol, and diindolylmethane); blood thinners or antiplatelet drugs (moderate risk from indole-3-carbinol and diindolylmethane); chemotherapy or alkylating agents (moderate risk from vitamin C); warfarin or other blood thinners (moderate risk from vitamin C); levothyroxine or other thyroid medications (moderate risk from vitamin C); diuretics, especially sodium-depleting ones (moderate risk from diindolylmethane); or acid-blocking medications like H2-blockers, antacids, or PPIs (minor risk from betaine HCl). These are the most important categories—use the medication checker for a full review of your current drugs.

Check your own medication Run your meds through the checker above

The bottom line

Scorecard at a glanceFully disclosed formula with strong clinical evidence behind its ingredients' uses. Moderate medication interactions have been identified, and safety information is well characterized.

I3C Plus is a four-ingredient supplement with limited effectiveness evidence for most of its components and significant documented interactions, particularly with estrogen therapies, blood thinners, and chemotherapy. If you take any prescription medications, especially hormonal contraceptives, anticoagulants, or chemotherapy drugs, check this product against your specific medications before starting.

Talk with your doctor or pharmacist about whether it's right for you.

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

Assessment coverage: 4 of 4 active ingredients matched to our full ingredient reviews (monographs). Based on the product label dated Jun 25, 2014.

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 I3C Plus, straight from the product label.

Brand Health Products Distributors
Net contents 120 Capsule(s)
Market status On market
Date entered into DSLD Jun 25, 2014
DSLD ID 34044
Product type Non-nutrient/non-botanical
Supplement form Capsule
Dietary claims / uses Nutrient, All Other, Qualified Health
Intended target group(s) Adult (18 - 50 Years), Gluten Free, Dairy Free, Sugar 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 I3C Plus by Health Products Distributors, 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:
4 Capsule(s)
IngredientAmount% DV
Vitamin C30 mg50%
Betaine HCl60 mg--
Indole-3-Carbinol60 mg--
Diindolymethane60 mg--

Other ingredients: Gelatin Capsule, Microcrystalline Cellulose, Silica, Magnesium Trisilicate

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.
Storage

STORE IN A COOL, DRY PLACE

Precautions

KEEP OUT OF REACH OF CHILDREN

Seals/Symbols

pdi

Formula

Indole-3-Carbinol (I3C) Diindolylmethane (DIM) plus Betaine HCl and Ascorbic Acid

FDA Statement of Identity

A Dietary Supplement

Suggested/Recommended/Usage/Directions

DIRECTIONS: As a dietary supplement take 2-4 capsules daily with food, or as directed by a health professional.

General Statements

Indole-3-Carbinol (I3C) and Diindolylmethane (DIM) are substances found in cruciferous vegetables such as broccoli, cauliflower, cabbage, and brussels sprouts. Research studies indicate that daily consumption of these substances in appropriate amounts may provide significant health benefits.

Formulation

I3C Plus Does Not Contain: wheat, rye, oats, corn, barley, gluten, soy, egg, dairy, citrus, yeast, sugar, wax, preservatives, colorings, or artificial flavorings.

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

See for yourself

I3C Plus by Health Products Distributors label

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

I3C Plus 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 I3C Plus by Health Products Distributors

These are the 4 active ingredients this product is made of. Select any to open its full monograph.

Serving size2 Capsule(s) Dosage formCapsule 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.

Vitamin C

Interacts with
207 drugs
30 mg per serving Form: Ascorbic Acid

Vitamin C (ascorbic acid) is an essential nutrient your body needs but cannot make, so you must get it from food or supplements. It's important for im...

Vitamin C monograph & interactions

Betaine HCl

Interacts with
36 drugs
60 mg per serving

Betaine hydrochloride is a supplement used to temporarily increase stomach acid in people who may have low acid levels. Evidence for its benefits is l...

Betaine HCl monograph & interactions

Indole-3-Carbinol

Interacts with
294 drugs
60 mg per serving

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...

Indole-3-Carbinol monograph & interactions

Diindolymethane

Interacts with
269 drugs
60 mg per serving

Diindolylmethane (DIM) is a compound made when your body digests cruciferous vegetables, and it is sold as a supplement mainly for hormone balance and...

Diindolymethane monograph & interactions

Other (inactive) ingredients: Gelatin Capsule, Microcrystalline Cellulose, Silica, Magnesium Trisilicate. These complete the product’s ingredient list but are not active constituents.

Interaction report

I3C Plus by Health Products Distributors Drug Interactions

Want to check YOUR meds against I3C Plus?

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
446Drugs
417 Moderate 29 Minor

Ingredients driving the most interactions

Indole-3-Carbinol 294
Diindolymethane 269
Vitamin C 207
Betaine HCl 36

Individual Drug Interactions

The ingredients in I3C Plus interact with 446 drugs. Click any drug to see the details.

4 of the 4 ingredients in I3C Plus interact with drugs. Each result below shows which ingredient is responsible. Indole-3-Carbinol Diindolymethane Vitamin C Betaine HCl

Each ingredient & the kinds of drugs it affects

For each ingredient in I3C Plus 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

Diindolymethane3 drug types · 269 drugs

Diuretic Drugs

Theoretically, diindolylmethane might increase the risk of hyponatremia if used with sodium-depleting diuretics.
Large doses of diindolylmethane (600 mg daily) have been associated with two cases of asymptomatic hyponatremia in clinical research.

Likelihood Possible Evidence B
Estrogens

Theoretically, diindolylmethane might increase or decrease the effects of estrogens.
Diindolylmethane might have mild estrogenic or antiestrogenic effects. Theoretically, large amounts of diindolylmethane might interfere with hormone replacement therapy.

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

Theoretically, diindolylmethane might lower serum levels of CYP1A2 substrates.
In vitro evidence suggests that diindolylmethane can induce CYP1A2. Theoretically, it might increase metabolism of CYP1A2 substrates and lower serum concentrations. This interaction has not been reported in humans.

Likelihood Unlikely Evidence D
Diindolymethane full monograph & interactions

Vitamin C13 drug types · 207 drugs

Alkylating Agents

Theoretically, antioxidant effects of vitamin C might reduce the effectiveness of alkylating agents.
The use of antioxidants like vitamin C during chemotherapy is controversial. There is concern that antioxidants could reduce the activity of chemotherapy drugs that generate free radicals, such as cyclophosphamide, chlorambucil, carmustine, busulfan, and thiotepa. In contrast, some researchers theorize that antioxidants might make chemotherapy more effective by reducing oxidative stress that could interfere with apoptosis (cell death) of cancer cells. More evidence is needed to determine what effect, if any, antioxidants such as vitamin C have on chemotherapy.

Likelihood Possible Evidence D
Aluminum

Vitamin C can increase the amount of aluminum absorbed from aluminum compounds.
Research in animals and humans shows that vitamin C increases aluminum absorption, theoretically by chelating aluminum and keeping it in solution where it is available for absorption. In people with normal renal function, urinary excretion of aluminum will likely increase, making aluminum retention and toxicity unlikely. Patients with renal failure who take aluminum-containing compounds such as phosphate binders should avoid vitamin C supplements in doses above the recommended dietary allowances.

Likelihood Probable Evidence B
Antitumor Antibiotics

Theoretically, the antioxidant effects of vitamin C might reduce the effectiveness of antitumor antibiotics.
The use of antioxidants like vitamin C during chemotherapy is controversial. There is concern that antioxidants could reduce the activity of chemotherapy drugs which generate free radicals, such as doxorubicin. In contrast, some researchers theorize that antioxidants might make chemotherapy more effective by reducing oxidative stress that could interfere with apoptosis (cell death) of cancer cells. More evidence is needed to determine what effects, if any, antioxidants such as vitamin C have on chemotherapy.

Likelihood Possible Evidence D
Estrogens

Vitamin C might increase blood levels of estrogens.
Increases in plasma estrogen levels of up to 55% occur under some circumstances when vitamin C is taken concurrently with oral contraceptives or hormone replacement therapy, including topical products. It is suggested that vitamin C prevents oxidation of estrogen in the tissues, regenerates oxidized estrogen, and reduces sulfate conjugation of estrogen in the gut wall. When tissue levels of vitamin C are high, these processes are already maximized and supplemental vitamin C does not have any effect on estrogen levels. Increases in plasma estrogen levels may occur when patients who are deficient in vitamin C take supplements. Monitor these patients for estrogen-related side effects.

Likelihood Probable Evidence B
Fluphenazine (Prolixin)

Theoretically, vitamin C might decrease levels of fluphenazine.
In one patient there was a clinically significant decrease in fluphenazine levels when vitamin C (500 mg twice daily) was started. The mechanism is not known, and there is no further data to confirm this interaction.

Likelihood Possible Evidence D
Indinavir (Crixivan)

Vitamin C can modestly reduce indinavir levels.
One pharmacokinetic study shows that taking vitamin C 1 gram orally once daily along with indinavir 800 mg orally three times daily reduces the area under the concentration-time curve of indinavir by 14%. The mechanism of this interaction is unknown, but it is unlikely to be clinically significant in most patients. The effect of higher doses of vitamin C on indinavir levels is unknown.

Likelihood Probable Evidence B
Levothyroxine (Synthroid, Others)

Vitamin C can increase levothyroxine absorption.
Two clinical studies in adults with poorly controlled hypothyroidism show that swallowing levothyroxine with a glass of water containing vitamin C 500-1000 mg in solution reduces thyroid stimulating hormone (TSH) levels and increases thyroxine (T4) levels when compared with taking levothyroxine alone. This suggests that vitamin C increases the oral absorption of levothyroxine, possibly due to a reduction in pH.

Likelihood Probable Evidence B
Warfarin (Coumadin)

High-dose vitamin C might reduce the levels and effectiveness of warfarin.
Vitamin C in high doses may cause diarrhea and possibly reduce warfarin absorption. There are reports of two people who took up to 16 grams daily of vitamin C and had a reduction in prothrombin time. Lower doses of 5-10 grams daily can also reduce warfarin absorption. In many cases, this does not seem to be clinically significant. However, a case of warfarin resistance has been reported for a patient who took vitamin C 500 mg twice daily. Cessation of vitamin C supplementation resulted in a rapid increase in international normalized ratio (INR). Tell patients taking warfarin to avoid taking vitamin C in excessively high doses (greater than 10 grams daily). Lower doses may be safe, but the anticoagulation activity of warfarin should be monitored. Patients who are stabilized on warfarin while taking vitamin C should avoid adjusting vitamin C dosage to prevent the possibility of warfarin resistance.

Likelihood Possible Evidence D
Acetaminophen (Tylenol, Others)

High-dose vitamin C might slightly prolong the clearance of acetaminophen.
A small pharmacokinetic study in healthy volunteers shows that taking high-dose vitamin C (3 grams) 1.5 hours after taking acetaminophen 1 gram slightly increases the apparent half-life of acetaminophen from around 2.3 hours to 3.1 hours. Ascorbic acid competitively inhibits sulfate conjugation of acetaminophen. However, to compensate, elimination of acetaminophen glucuronide and unconjugated acetaminophen increases. This effect is not likely to be clinically significant.

Likelihood Probable Evidence B
Aspirin

Acidification of the urine by vitamin C might increase aspirin levels.
It has been suggested that acidification of the urine by vitamin C could increase reabsorption of salicylates by the renal tubules, and increase plasma salicylate levels. However, short-term use of up to 6 grams daily of vitamin C does not seem to affect urinary pH or salicylate excretion, suggesting this interaction is not clinically significant.

Likelihood Possible Evidence B
Choline Magnesium Trisalicylate (Trilisate)

Acidification of the urine by vitamin C might increase choline magnesium trisalicylate levels.
It has been suggested that acidification of the urine by vitamin C could increase reabsorption of salicylates by the renal tubules, and increase plasma salicylate levels. However, short-term use of up to 6 grams daily of vitamin C does not seem to affect urinary pH or salicylate excretion, suggesting this interaction probably is not clinically significant.

Likelihood Possible Evidence B
Niacin

Vitamin C might decrease the beneficial effects of niacin on high-density lipoprotein (HDL) cholesterol levels.
A combination of niacin and simvastatin (Zocor) effectively raises HDL cholesterol levels in patients with coronary disease and low HDL levels. Clinical research shows that taking a combination of antioxidants (vitamin C, vitamin E, beta-carotene, and selenium) along with niacin and simvastatin (Zocor) attenuates this rise in HDL, specifically the HDL-2 and apolipoprotein A1 fractions, by more than 50% in patients with coronary disease. It is not known whether this adverse effect is due to a single antioxidant such as vitamin C, or to the combination. It also is not known whether it will occur in other patient populations.

Likelihood Possible Evidence A
Salsalate (Disalcid)

Acidification of the urine by vitamin C might increase salsalate levels.
It has been suggested that acidification of the urine by vitamin C could increase reabsorption of salicylates by the renal tubules, and increase plasma salicylate levels. However, short-term use of up to 6 grams/day vitamin C does not seem to affect urinary pH or salicylate excretion, suggesting this interaction probably is not clinically significant.

Likelihood Possible Evidence B
Vitamin C full monograph & interactions

Betaine HCl3 drug types · 36 drugs

Antacids

Betaine hydrochloride increases stomach acidity and could decrease the effects of antacids.
In human research, betaine hydrochloride increases stomach acidity. Antacids are taken to decrease stomach acidity. Theoretically, taking betaine hydrochloride along with antacids might decrease the effects of the antacids.

Likelihood Possible Evidence D
H2-Blockers

Betaine hydrochloride increases stomach acidity and could decrease the effects of H2-blockers.
In human research, betaine hydrochloride increases stomach acidity. H2-blockers are used to decrease stomach acidity. Theoretically, taking betaine hydrochloride along with H2-blockers might decrease the effects of H2-blockers.

Likelihood Possible Evidence D
Proton Pump Inhibitors (Ppis)

Betaine hydrochloride increases stomach acidity and could decrease the effects of PPIs.
In human research, betaine hydrochloride increases stomach acidity. PPIs are used to decrease stomach acidity. Theoretically, taking betaine hydrochloride along with PPIs might decrease the effects of PPIs

Likelihood Possible Evidence D
Betaine HCl full monograph & interactions
The maker

Brand information

Manufacturer and brand details for I3C Plus, from the product label.

Health Products Distributors

See all Health Products Distributors products
Name
Health Products Distributors, Inc.
Street Address
PO Box 5600
City
Oracle
State
AZ
ZipCode
85623
Pharmacist Counseling Corner

I3C Plus by Health Products Distributors: Common Questions

Does I3C Plus by Health Products Distributors interact with any medications?
Yes. Based on its ingredients, I3C Plus has a known interaction with 446 medications. Use the checker to see how it interacts with a specific drug.
How can one product interact with so many drugs?
I3C Plus contains 4 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.
Is I3C Plus safe to take while pregnant?
Vitamin C at normal dietary amounts and prenatal vitamin doses is considered likely safe in pregnancy; the data advises avoiding high-dose supplements unless your doctor recommends them. For indole-3-carbinol and diindolylmethane, there isn't enough safety data—the facts advise against these supplements in pregnancy. Since this product combines all four, talk with your obstetrician or pharmacist before taking it while pregnant.
Is it safe to breastfeed while taking I3C Plus?
Safety information during breastfeeding is limited for most ingredients. Betaine HCl and indole-3-carbinol are best avoided while nursing because safety hasn't been established. Diindolylmethane is rated likely safe, but the overall safety of the combined product while breastfeeding hasn't been studied. Check with your doctor or pharmacist before taking it.
What does indole-3-carbinol (I3C) actually do?
Indole-3-carbinol is a compound from cruciferous vegetables like broccoli and cabbage, included for its potential effects on how your body handles estrogen and on cell health. However, the evidence we hold shows insufficient reliable evidence to rate its effectiveness for conditions like cancer prevention or hormone-related issues.
Can I take I3C Plus with my birth control or hormone replacement?
No—this product contains three ingredients (vitamin C, indole-3-carbinol, and diindolylmethane) that interact moderately with estrogens. Vitamin C alone can increase blood estrogen levels by up to 55%, and the others may interfere with how your hormones work. Talk with your prescriber before combining it with hormonal medications.
Does this product have side effects?
Vitamin C at high doses can cause stomach cramps, diarrhea, nausea, and heartburn. Betaine HCl may irritate the stomach and cause heartburn. Indole-3-carbinol and diindolylmethane are generally well tolerated but may cause diarrhea, nausea, gas, rash, and headache. At the doses in this product, most people tolerate it, but talk with your pharmacist if you have a sensitive stomach or stomach ulcers.
What does betaine HCl do?
Betaine HCl is a form of betaine bound to hydrochloric acid, intended to support your stomach's natural acid production. It's included for digestive support, but the evidence we hold shows insufficient reliable evidence to rate its effectiveness for digestive issues like dyspepsia.

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.

I3C Plus label
Go deeper

The Full Monographs Behind I3C Plus’s Ingredients

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

Herb & supplement monograph

Vitamin C

Interacts with 207 drugs

Vitamin C (ascorbic acid) is an essential nutrient your body needs but cannot make, so you must get it from food or supplements. It's important for immune function, collagen, and acts as an...

Read the full Vitamin C monograph → Herb & supplement monograph

Betaine Hydrochloride

Interacts with 36 drugs

Betaine hydrochloride is a supplement used to temporarily increase stomach acid in people who may have low acid levels. Evidence for its benefits is limited and mostly based on tradition rat...

Read the full Betaine Hydrochloride monograph → 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

Diindolylmethane

Interacts with 269 drugs

Diindolylmethane (DIM) is a compound made when your body digests cruciferous vegetables, and it is sold as a supplement mainly for hormone balance and cancer prevention. Although early lab s...

Read the full Diindolylmethane monograph →
Sources

Sources & How We Checked

I3C Plus'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 76 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.

Vitamin C 51 references
  1. McEvoy GK, ed. AHFS Drug Information. Bethesda, MD: American Society of Health-System Pharmacists, 1998.
  2. Back DJ, Breckenridge AM, MacIver M, et al. Interaction of ethinyloestradiol with ascorbic acid in man. Br Med J (Clin Res Ed) 1981;282:1516.
  3. Morris JC, Beeley L, Ballantine N. Interaction of ethinyloestradiol with ascorbic acid in man [letter]. Br Med J (Clin Res Ed) 1981;283:503.
  4. Labriola D, Livingston R. Possible interactions between dietary antioxidants and chemotherapy. Oncology 1999;13:1003-8.
  5. Dwyer JH, Merz NB, Shirocre AM, et al. Progression of early atherosclerosis and intake of vitamin C and vitamin E from supplements and food. The Los Angeles Atherosclerosis Study. 41st Annual Conference on Cardiovascular Disease Epidemiology and Prevent
  6. Levine M, Rumsey SC, Daruwala R, et al. Criteria and recommendations for vitamin C intake. JAMA 1999;281:1415-23. PubMed
  7. Hansten PD, Horn JR. Drug Interactions Analysis and Management. Vancouver, WA: Applied Therapeutics Inc., 1997 and updates.
  8. Segal S, Kaminski S. Drug-nutrient interactions. American Druggist 1996 Jul;42-8.
  9. Food and Nutrition Board, Institute of Medicine. Dietary Reference Intakes for Vitamin C, Vitamin E, Selenium, and Carotenoids. Washington, DC: National Academy Press, 2000. Available at: http://www.nap.edu/books/0309069351/html/.
  10. Houston JB, Levy G. Drug biotransformation interactions in man VI: Acetaminophen and ascorbic acid. J Pharm Sci 1976;65:1218-21. PubMed
  11. Brown BG, Zhao XQ, Chait A, et al. Simvastatin and niacin, antioxidant vitamins, or the combination for the prevention of coronary disease. N Engl J Med 2001;345:1583-93. DOI
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Betaine Hydrochloride 2 references
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Diindolylmethane 14 references
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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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