Skip to main content
Supplement ScienceSupplementScience

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

Evidence:Moderate
·

This content is for informational purposes only and does not constitute medical advice. Statements about dietary supplements have not been evaluated by the FDA and are not intended to diagnose, treat, cure, or prevent any disease. Individual results may vary — consult your healthcare provider before starting any supplement. Full disclaimer

Forms Comparison

FormBioavailabilityBest For
I3C CapsulesModerate (variable stomach pH-dependent conversion)HPV-related conditions — most clinical studies used I3C directly; for estrogen modulation, DIM is often preferred
Cruciferous Vegetable ExtractLow-ModerateBroad cruciferous benefits — provides I3C alongside other glucosinolates (sulforaphane precursors)

I3C Capsules

Bioavailability: Moderate (variable stomach pH-dependent conversion). Best for: HPV-related conditions — most clinical studies used I3C directly; for estrogen modulation, DIM is often preferred.

Cruciferous Vegetable Extract

Bioavailability: Low-Moderate. Best for: Broad cruciferous benefits — provides I3C alongside other glucosinolates (sulforaphane precursors).

References

  1. ObservationalRosen CA, Bryson PC (1998). Indole-3-carbinol for recurrent respiratory papillomatosis: long-term results. Journal of Voice. DOI PubMed
  2. RCTBell MC, Crowley-Nowick P, Bradlow HL, et al. (2000). Placebo-controlled trial of indole-3-carbinol in the treatment of CIN. Gynecologic Oncology. DOI PubMed
  3. ObservationalReed GA, Arneson DW, Putnam WC, et al. (2006). Single-dose and multiple-dose administration of indole-3-carbinol to women: pharmacokinetics based on 3,3'-diindolylmethane. Cancer Epidemiology, Biomarkers & Prevention. DOI PubMed
  4. ReviewHigdon JV, Delage B, Williams DE, Dashwood RH (2007). Cruciferous vegetables and human cancer risk: epidemiologic evidence and mechanistic basis.. Pharmacological research. DOI PubMed