Types of I3C (Indole-3-Carbinol): Forms & Bioavailability

SupplementScience.ai Editorial Team·Evidence-Based Supplement Research

Published Mar 11, 2026

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Forms Comparison

Form	Bioavailability	Best For
I3C Capsules	Moderate (pH-dependent conversion)	General hormonal support — most common supplemental form
I3C + DIM Combination	Moderate-High	Comprehensive estrogen metabolism support — covers both precursor and active metabolite

I3C Capsules

Bioavailability: Moderate (pH-dependent conversion). Best for: General hormonal support — most common supplemental form.

I3C + DIM Combination

Bioavailability: Moderate-High. Best for: Comprehensive estrogen metabolism support — covers both precursor and active metabolite.

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