Indole-3-carbinol

Also known as I3C, indole 3 carbinol.

Last reviewed October 9, 2026 · Jump to references

What is Indole-3-carbinol?

In plain words

Indole-3-carbinol is a substance formed when vegetables such as broccoli and cabbage are chopped or chewed. Stomach acid changes it into other compounds that can affect how the body processes estrogen. Researchers study it for these hormone effects and its possible role in cancer prevention. Human studies have not established that I3C supplements prevent cancer.

Technical definition

Indole-3-carbinol (I3C) is an indole phytochemical formed when the glucosinolate glucobrassicin in cruciferous vegetables is broken down by the enzyme myrosinase. In stomach acid, I3C forms condensation products, including 3,3′-diindolylmethane (DIM), which influence aryl hydrocarbon receptor signaling and enzymes involved in estrogen metabolism. I3C is marketed as a dietary supplement in the United States but is not FDA-approved to prevent or treat disease.

Educational information only. This page does not provide medical advice or determine whether a supplement is appropriate for you. Review supplements with a qualified healthcare professional, especially if you take medication, are pregnant, have surgery scheduled, or have a chronic medical condition.

Evidence by use

Each use is rated on its own. There is no single overall effectiveness score.