Indole-3-carbinol: What It Is and Why People Use It
Indole-3-carbinol (I3C) is a plant compound you get when you eat cruciferous vegetables like broccoli, cabbage, and Brussels sprouts. In the body it changes into several active molecules that affect hormone breakdown, inflammation, and cell signaling. People take I3C supplements for hormone balance, to support liver detox, or because early studies suggest it may lower risk factors linked to some cancers.
If you want practical info, here it is: food gives small amounts of I3C, while supplements pack a much higher dose. That means you can get benefits from both diet and pills, but they act differently. Whole foods supply fiber, vitamins, and other nutrients; supplements give a concentrated, predictable amount of I3C.
What the evidence shows (short version)
Most research on I3C started in labs and animal studies. These show I3C can change how the body metabolizes estrogen and reduce certain cancer markers. A few small human trials looked at markers for breast and cervical health and reported promising changes, but large clinical trials are still missing. So I3C looks useful, but it’s not a proven treatment for disease.
How people use I3C and common doses
Common supplement doses range from about 200 to 400 mg per day, often split into two doses. Some practitioners use higher short-term doses under supervision. If you start a supplement, begin with the lower end and watch for side effects. Taking I3C with food can cut stomach upset.
Want more natural? Eat a cup or two of cooked cruciferous vegetables most days. Cooking reduces bitterness and still gives the precursors your body turns into I3C.
Safety matters. I3C can change hormone levels and may speed up or slow down how your liver breaks down some drugs. That means it can interact with medications like blood thinners or hormone therapies. If you’re pregnant, breastfeeding, on prescription drugs, or have hormone-sensitive cancer, check with your doctor before trying I3C.
Side effects are usually mild: stomach upset, headache, or a change in urine smell. Rare reports note liver enzyme changes or increased thyroid hormone breakdown, so routine use at high doses calls for medical monitoring.
Choosing a supplement: pick brands that show third-party testing (USP, NSF, or similar). Look for clear labeling of I3C amount per capsule, and avoid products that promise unrealistic cures. If you prefer a related option, diindolylmethane (DIM) is a more stable compound formed from I3C and often used for similar goals.
Quick checklist: eat cruciferous veggies regularly, consider a low-dose supplement if you have a clear reason, start low and watch for side effects, and always talk to your clinician if you take meds or have health conditions. That way you get the potential benefits without unnecessary risk.