{"entity":{"id":"indole-3-carbinol","kind":"technology","name":"Indole-3-carbinol (I3C)","aka":["I3C","Indole-3-methanol"],"tldr":"Indole-3-carbinol comes from broccoli, cabbage and other cruciferous vegetables, and diets rich in these vegetables are linked to lower cancer risk. Capsules have shown activity in early trials for precancerous changes of the cervix and vulva, but some laboratory models show it can also promote cancer growth, and the benefit of vegetables may not need high-dose supplements.","summary":"Indole-3-carbinol forms when glucosinolates in cruciferous vegetables are broken down. Memorial Sloan Kettering's About Herbs entry notes that diets high in these vegetables are associated with lower cancer risk and that laboratory studies show activity against many cancer cell types and possible enhancement of drugs such as tamoxifen, doxorubicin and bortezomib; however, these effects have not been confirmed in people and some models suggest I3C may promote tumour growth. Early phase trials suggested effects on cervical dysplasia and vulval intraepithelial neoplasia, and supplements shift urinary oestrogen metabolite ratios, a biomarker rather than an outcome. MSK concludes it is unclear whether supplements benefit humans given the mixed preliminary results and I3C's ability to induce cytochrome P450 enzymes (CYP1A2 in laboratory studies), which could cause drug interactions, and notes a study suggesting the protective effect of eating cruciferous vegetables may plateau without large quantities or supplements. It is generally well tolerated; skin rash and rare small rises in liver enzymes are reported.","status":"phase-2","asOf":"2026-11-04","links":[{"label":"MSK About Herbs: Indole-3-carbinol (page last updated 2 August 2023)","url":"https://www.mskcc.org/cancer-care/integrative-medicine/herbs/indole-3-carbinol"}],"tags":["complementary","supportive-care","evidence:insufficient"],"related":["diindolylmethane-dim","resveratrol-supplements"],"cancers":[],"sections":["supportive-care","prevention","nutrition-lifestyle"],"technologies":["integrative-oncology","dietary-supplements-treatment-interactions","mediterranean-plant-forward-diet"],"targets":[],"drugs":[],"companies":[],"institutions":[],"pathways":[],"terms":["unproven-diet-claims"],"trials":[],"people":[],"bottlenecks":["b-misinformation"],"keyPapers":[],"journals":[],"dependsOn":[],"notes":[],"principle":"In the acid of the stomach I3C condenses into diindolylmethane and other compounds that bind the aryl hydrocarbon receptor, change oestrogen metabolism and induce drug-metabolising enzymes.","strengths":["Early trials in cervical and vulval precancers","Eating the vegetables it comes from is safe and sensible"],"limitations":["No proof that supplements prevent cancer","Some models show tumour promotion","Induces drug-metabolising enzymes"]},"route":"/technologies/indole-3-carbinol/","neighbours":{"technology":[{"id":"dietary-supplements-treatment-interactions","kind":"technology","name":"Dietary supplements during cancer treatment: interactions and harms","route":"/technologies/dietary-supplements-treatment-interactions/"},{"id":"diindolylmethane-dim","kind":"technology","name":"Diindolylmethane (DIM)","route":"/technologies/diindolylmethane-dim/"},{"id":"integrative-oncology","kind":"technology","name":"Evidence-based integrative oncology","route":"/technologies/integrative-oncology/"},{"id":"mediterranean-plant-forward-diet","kind":"technology","name":"Mediterranean and plant-forward dietary patterns","route":"/technologies/mediterranean-plant-forward-diet/"},{"id":"resveratrol-supplements","kind":"technology","name":"Resveratrol supplements","route":"/technologies/resveratrol-supplements/"}],"section":[{"id":"nutrition-lifestyle","kind":"section","name":"Diet, Exercise & Lifestyle","route":"/fronts/nutrition-lifestyle/"},{"id":"prevention","kind":"section","name":"Prevention & Risk","route":"/fronts/prevention/"},{"id":"supportive-care","kind":"section","name":"Supportive Care & Survivorship","route":"/fronts/supportive-care/"}],"term":[{"id":"unproven-diet-claims","kind":"term","name":"Unproven diet claims (alkaline, juice, 'anti-cancer' diets)","route":"/terms/unproven-diet-claims/"}],"bottleneck":[{"id":"b-misinformation","kind":"bottleneck","name":"Misinformation and unproven therapies","route":"/bottlenecks/b-misinformation/"}]}}