Supplement
I3C (Indole-3-Carbinol)
SaveA compound derived from cruciferous vegetables that modulates estrogen metabolism. Converted in the stomach to DIM and other metabolites that shift estrogen toward less potent forms.
Quick verdict
Reasonable evidence for modulating estrogen metabolism; studied for cancer prevention but not yet proven. DIM may be a more consistent choice due to I3C's variable conversion.
Evidence score
A rough internal score reflecting quantity, quality, and consistency of human evidence. Not a clinical recommendation.
What the research shows
I3C upregulates CYP1A1 and shifts estrogen metabolism toward 2-hydroxyestrone (less proliferative) over 16-alpha-hydroxyestrone. Clinical studies show changes in urinary estrogen metabolite ratios. Being investigated for cervical dysplasia and breast cancer prevention. Conversion to DIM and other products is pH-dependent and variable.
Benefits
- Modulates estrogen metabolism toward less potent forms
- May support healthy estrogen balance
- Under investigation for cervical and breast health
Dosage notes
Typical doses range from 200-400 mg daily. Best taken with food to facilitate gastric acid conversion to DIM.
Side effects
- GI discomfort
- Skin rash in some individuals
- May alter hormone levels
Who should be cautious
May interact with medications metabolized by CYP enzymes. Long-term safety at high doses not established. Theoretical concern about tumor promotion at very high doses in some animal models.
What this page cannot tell you
Conversion to active metabolites is variable and pH-dependent. DIM supplementation may provide more consistent effects. Cancer prevention data is preliminary.
Leaderboard scores
- Longevity35
- Immunity30
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