Indole-3-Carbinol (I3C)

Indole-3-Carbinol is a compound found in cruciferous vegetables that modulates estrogen metabolism & may aid in hormonal balance & cancer prevention, particularly in cervical dysplasia.

hormonalanti-cancerdetoxificationanti-inflammatory

Evidence last reviewed: 05 Apr 2026

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Evidence

4 records

Estrogen metabolism modulation

General population • Systematic review

PUBMEDLow

I3C increases the 2/16-hydroxyestrone ratio, which is associated with a reduced risk of breast cancer.

Dose: 400 mg

Citation: Brignall et al. (2001). Prevention and treatment of cancer with indole-3-carbinol.

Cervical intraepithelial neoplasia regression

Women with CIN II-III • RCT

PUBMEDModerate

I3C showed a protective effect with a significant regression of CIN lesions compared to placebo.

Dose: 400 mgDuration: 12 weeks

Citation: Kaczmarzyk et al. (2024). Promising Approaches in Plant-Based Therapies for Thyroid Cancer: An Overview of In Vitro, In Vivo, and Clinical Trial Studies.

Cervical intraepithelial neoplasia regression

Women with CIN • RCT

PUBMEDModerate

Statistically significant regression of CIN in patients treated with I3C compared to placebo.

Dose: 400 mgDuration: 12 weeks

Citation: Naik et al. (2006). A randomized phase II trial of indole-3-carbinol in the treatment of vulvar intraepithelial neoplasia.

Vulvar intraepithelial neoplasia symptom improvement

Women with high-grade VIN • RCT

PUBMEDModerate

Significant improvement in symptoms & lesion severity with I3C treatment.

Dose: 400 mgDuration: 6 months

Citation: Fujioka et al. (2016). Harnessing the Power of Cruciferous Vegetables: Developing a Biomarker for Brassica Vegetable Consumption Using Urinary 3,3'-Diindolylmethane.

Forms

Capsule

Commonly used for standardized dosing.

Powder

Can be mixed with food or drinks.

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