I3C (Indole-3-Carbinol) Research & Evidence

SupplementScience.ai Editorial Team·Evidence-Based Supplement Research

Published Mar 11, 2026

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Evidence Level

Moderate

I3C has been studied for estrogen metabolism modulation since the early 1990s. Bradlow et al. first demonstrated its ability to shift estrogen metabolism toward 2-hydroxylation. A notable pilot study by Bell et al. (2000) in Gynecologic Oncology showed 50% regression of CIN 2-3 at 200-400mg daily over 12 weeks. However, the variable metabolite profile created during gastric acid conversion has led many practitioners to recommend DIM as a more predictable alternative.

Evidence by Condition

Condition	Studied Dose	Evidence
Estrogen metabolism	200-400mg daily	Moderate
Cervical dysplasia support	200-400mg daily	Emerging
General detoxification	200mg daily	Preliminary

Full I3C (Indole-3-Carbinol) Guide

References

Bell MC, Crowley-Nowick P, Bradlow HL, Sepkovic DW, Schmidt-Grimminger D, Howell P, Mayeaux EJ, Tucker A, Turbat-Herrera EA, Mathis JM (2000). Placebo-controlled trial of indole-3-carbinol in the treatment of CIN. Gynecologic Oncology. DOI PubMed
Reed GA, Arneson DW, Putnam WC, Smith HJ, Gray JC, Sullivan DK, Mayo MS, Crowell JA, Hurwitz A (2005). Single-dose and multiple-dose administration of indole-3-carbinol to women: pharmacokinetics based on 3,3'-diindolylmethane. Cancer Epidemiology, Biomarkers & Prevention. DOI PubMed