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Indole-3-Carbinol (I3C) — Frequently Asked Questions

This content is for informational purposes only and does not constitute medical advice. Consult your healthcare provider before starting any supplement. Full disclaimer

Frequently Asked Questions

Should I take I3C or DIM for estrogen balance?

For most people, DIM is the better choice for estrogen metabolism support. I3C must be converted to DIM (and other metabolites) in the stomach, and this conversion is variable depending on stomach pH, meal composition, and individual factors. DIM supplements deliver the active metabolite directly, providing more predictable and consistent effects. The main exception is HPV-related conditions, where the clinical studies specifically used I3C, and other I3C metabolites (not just DIM) may contribute to the therapeutic effect.

How much broccoli would I need to eat to get a therapeutic dose of I3C?

You would need to eat approximately 300-500g (about 2-3 cups) of raw broccoli daily to approach the 200-400mg I3C dose used in clinical studies. Cooking reduces glucosinolate content by 30-60% depending on method. While regular cruciferous vegetable consumption is beneficial for health, achieving therapeutic I3C levels through diet alone is impractical for most people, which is why supplements exist.

Can I3C help with HPV?

I3C has shown specific promise for HPV-related conditions. Rosen et al. (1998) found that 200mg daily helped control recurrent respiratory papillomatosis (RRP). Bell et al. (2000) demonstrated CIN regression in women taking I3C. The mechanism likely involves both immune modulation and direct effects on HPV-infected cell proliferation. However, I3C is not a treatment for HPV infection itself — it may help manage HPV-related cellular changes. Always work with your healthcare provider for HPV-related conditions.

Full Indole-3-Carbinol (I3C) Guide

References

  1. (). Indole-3-carbinol for recurrent respiratory papillomatosis: long-term results. Journal of Voice.
  2. (). Placebo-controlled trial of indole-3-carbinol in the treatment of CIN. Gynecologic Oncology. DOI
  3. (). Single-dose and multiple-dose administration of indole-3-carbinol to women: pharmacokinetics based on 3,3'-diindolylmethane. Cancer Epidemiology, Biomarkers & Prevention. DOI