Evidence Level
I3C research spans estrogen metabolism, HPV-related conditions, and cancer prevention. Rosen et al. (1998) published a key study on recurrent respiratory papillomatosis showing that 200mg of I3C daily stopped papilloma growth in a third of patients. Bell et al. (2000) studied 30 women with CIN II-III and found that 200mg of I3C daily led to CIN regression in 50% of participants over 12 weeks. For estrogen metabolism, multiple studies confirm that I3C shifts the 2:16α-OHE1 ratio, though the effect is more variable than with DIM due to pH-dependent conversion kinetics. The 2017 consensus in the field has generally shifted to recommending DIM over I3C for estrogen modulation, as DIM bypasses the variable stomach conversion and provides a more consistent dose of the primary active metabolite.