ByDr. Brennan Commerford, Chiropractic Physician·Last reviewed: April 2026
All Ingredients
Specialty1 form

Indole-3-Carbinol (I3C)

Evidence Level
Moderate Evidence

Quick Answer

What is the best form of Indole-3-Carbinol (I3C)?

We compared 1 forms of Indole-3-Carbinol (I3C) in our formulary. Browse the comparison table below to find the best form for your goals.

1forms compared

All Forms of Indole-3-Carbinol (I3C)

FormTierBioavailabilityDose RangeUnit
I3CT2 SpecialistS2

Bioavailability by Form

S2 — Good
I3C

What is Indole-3-Carbinol (I3C)?

Indole-3-Carbinol (I3C) is a Specialty supplement available in 1 form.

Not all forms of Indole-3-Carbinol (I3C) are equal. The form you choose determines how much Indole-3-Carbinol (I3C) actually reaches your tissues, and the difference between the best and worst forms can be substantial. Indole-3-carbinol (I3C) is the natural cruciferous vegetable compound that converts to DIM and other acid condensation products in the stomach, providing a broader spectrum of indole metabolites than DIM alone. Research supports I3C for promoting healthy estrogen metabolism, Nrf2 pathway activation, and cellular health.

Forms of Indole-3-Carbinol (I3C) Compared

Indole-3-Carbinol (I3C) (T2 Specialist) has a bioavailability rating of good (S2). Typical dose range: not yet documented in our database.

What the Research Shows

Indole-3-Carbinol (I3C) is a glucosinolate breakdown product from cruciferous vegetables that supports Phase I estrogen metabolism. In the stomach, I3C converts to DIM and other metabolites. Research supports I3C for estrogen balance, with studies demonstrating shifts toward favorable 2-hydroxy estrogen metabolites. It complements DIM supplementation by providing upstream pathway support.

How to Choose the Right Form

Multiple forms of Indole-3-Carbinol (I3C) are available. Start by comparing formulary tiers — T1 Preferred forms reflect the strongest bioavailability evidence, and S1-rated forms deliver the most active compound per dose unit.

The appropriate form depends on your individual goals and your healthcare provider’s recommendations. Consult a qualified professional before selecting a supplement form.

Dosing & Safety

For Indole-3-Carbinol (I3C), the typical dosing range is not yet documented in our database. Individual dose requirements vary based on health goals, body weight, and existing nutrient intake.

Side Effects: Specific side effect data for these forms is not yet documented in our database. In general, consult your healthcare provider regarding tolerability at higher doses.

These statements are based on structure/function research and have not been evaluated by the FDA. This information is not intended to diagnose, treat, cure, or prevent any disease. Always consult a qualified healthcare provider before starting or changing a supplement regimen.

Dosing Guidance

Dosing information not yet available for this ingredient.

Frequently Asked Questions

What is the best form of Indole-3-Carbinol (I3C)?
Multiple forms of Indole-3-Carbinol (I3C) are available, each with different absorption characteristics. Our formulary classification data for Indole-3-Carbinol (I3C) is being compiled. Always consult a qualified healthcare provider before starting, stopping, or adjusting any supplement regimen.
How much Indole-3-Carbinol (I3C) should I take daily?
Dosing information for Indole-3-Carbinol (I3C) is being compiled in our database. Individual dose requirements vary based on health goals and existing nutrient intake. Always consult a qualified healthcare provider before starting, stopping, or adjusting any supplement regimen. These statements are based on structure/function research and have not been evaluated by the FDA. This information is not intended to diagnose, treat, cure, or prevent any disease.
What are the benefits of Indole-3-Carbinol (I3C)?
Indole-3-Carbinol (I3C) has been studied for its role in supporting: Supports healthy estrogen metabolism and Phase I detoxification, Supports cellular health via aryl hydrocarbon receptor modulation, Supports immune system balance, Supports antioxidant defense. Indole-3-Carbinol (I3C) is a glucosinolate breakdown product from cruciferous vegetables that supports Phase I estrogen metabolism. In the stomach, I3C converts to DIM and other metabolites. Research supports I3C for estrogen balance, with studies demonstrating shifts toward favorable 2-hydroxy estrogen metabolites. It complements DIM supplementation by providing upstream pathway support. These statements are based on structure/function research and have not been evaluated by the FDA. This information is not intended to diagnose, treat, cure, or prevent any disease.
When is the best time to take Indole-3-Carbinol (I3C)?
Optimal timing for Indole-3-Carbinol (I3C) supplementation depends on the specific form, dosage, and individual factors. Some forms may be better absorbed with food; others may not require food. Always consult a qualified healthcare provider before starting, stopping, or adjusting any supplement regimen.
Are there side effects of taking Indole-3-Carbinol (I3C)?
Tolerability of this Specialty supplement varies by individual, dose, and specific form. Some individuals may experience gastrointestinal discomfort at higher doses. Specific side effect profiles for each form of Indole-3-Carbinol (I3C) are documented in our formulary where available. Always consult a qualified healthcare provider before starting, stopping, or adjusting any supplement regimen. These statements are based on structure/function research and have not been evaluated by the FDA. This information is not intended to diagnose, treat, cure, or prevent any disease.
What forms of Indole-3-Carbinol (I3C) are available?
There are 1 form of Indole-3-Carbinol (I3C) in our formulary: Indole-3-Carbinol (I3C) (T2 Specialist, bioavailability: good (S2)). Forms differ in chemical structure, bioavailability, and typical dose range. FormulaForge classifies forms by tier based on published bioavailability evidence.

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FormulaForge formulates and sells supplements containing the ingredients discussed on this page. Our formulary recommendations are based on peer-reviewed bioavailability research. All cited studies are independently verifiable.