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.
Evidence last reviewed: 05 Apr 2026
The evidence for I3C shows moderate support for its role in improving symptoms of cervical dysplasia and enhancing estrogen metabolism. However, the overall strength of the evidence is mixed, with some studies showing significant benefits while others are less conclusive.
Estrogen metabolism modulationGeneral population · Systematic reviewLow
I3C increases the 2/16-hydroxyestrone ratio, which is associated with a reduced risk of breast cancer.
Cervical intraepithelial neoplasia regressionWomen with CIN II-III · RCTModerate
I3C showed a protective effect with a significant regression of CIN lesions compared to placebo.
Cervical intraepithelial neoplasia regressionWomen with CIN · RCTModerate
Statistically significant regression of CIN in patients treated with I3C compared to placebo.
Vulvar intraepithelial neoplasia symptom improvementWomen with high-grade VIN · RCTModerate
Significant improvement in symptoms & lesion severity with I3C treatment.
Forms & usage▾
Take 200-400 mg daily, preferably with meals.