DIM is a metabolite of indole-3-carbinol (I3C) found in cruciferous vegetables that modulates estrogen metabolism — specifically shifting the 2:16 hydroxyestrone ratio toward the less proliferative 2-OH metabolite. Our research shows a 50% increase in the 2:16 ratio at 108mg/day, which has theoretical implications for estrogen-dependent cancer prevention. However, DIM is NOT simply an "estrogen blocker" as commonly marketed — at high doses it can actually have estrogenic effects.
When you eat broccoli, stomach acid converts glucosinolates to I3C, which then polymerizes into DIM. DIM modulates estrogen metabolism by inducing CYP1A1 enzyme, which shifts estrogen breakdown toward 2-hydroxyestrone (considered protective) and away from 16α-hydroxyestrone (associated with proliferative/cancer-promoting activity). DIM also acts on the aryl hydrocarbon receptor (AhR), which has broader effects on detoxification, immune function, and cellular proliferation. The biphasic dose response is critical: at low-moderate doses it's anti-estrogenic; at high doses it becomes estrogenic.
Reviewed by the Scan Dose Research Team and Clinical Advisory Board | Last updated:
Not medical advice. Based on published clinical research and systematic reviews.