Research

Indole-3-Carbinol (I3C)

20 peer-reviewed studies curated from PubMed and Semantic Scholar.

3
Meta-analyses
0
Systematic reviews
13
RCTs
4
Other studies
Meta-analyses (15%)
RCTs (65%)
Observational (10%)

Studies

Sorted by quality and recency

2025·Journal of lower genital tract disease·Ana Carolina Simões, Ayane Cristine Sarmento, Antonio Carlos Aquino, et al

Treatment Interventions for Usual-Type Vulvar Intraepithelial Neoplasia: A Systematic Review and Meta-analysis.

Meta-analysis

Systematic review and meta-analysis evaluating treatments for usual-type vulvar intraepithelial neoplasia (uVIN). Imiquimod 5% showed significant lesion resolution compared to placebo, and sinecatechins 10% showed lesion improvement. Indole-3-carbinol and Omiganan were ineffective.

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2022·Journal of complementary & integrative medicine·Tim Green, Janet See, Marita Schauch, et al

A randomized, double-blind, placebo-controlled, cross-over trial to evaluate the effect of EstroSenseon 2-hydroxyestrone:16α-hydroxyestrone ratio in premenopausal women.

RCTn = 148Womens Health

RCT of 148 premenopausal women evaluating the effect of EstroSense, containing indole-3-carbinol and green-tea catechins, on urinary 2-hydroxyestrone:16α-hydroxyestrone ratio. EstroSense use led to a significantly higher ratio, associated with a lower risk of breast cancer.

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2015·The Cochrane database of systematic reviews·Litha Pepas, Sonali Kaushik, Andy Nordin, et al

Medical interventions for high-grade vulval intraepithelial neoplasia.

Meta-analysisn = 297

This meta-analysis evaluated the effectiveness and safety of non-surgical interventions for high-grade vulval intraepithelial neoplasia (VIN). It included five trials with 297 women, assessing topical imiquimod, cidofovir, and indole-3-carbinol. Imiquimod showed a significant response compared to placebo, while cidofovir was comparable to imiquimod. Indole-3-carbinol data was limited. Longer-term data is needed to confirm sustained treatment effects.

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2011·The Cochrane database of systematic reviews·Litha Pepas, Sonali Kaushik, Andrew Bryant, et al

Medical interventions for high grade vulval intraepithelial neoplasia.

Meta-analysis

Meta-analysis of four RCTs evaluating medical interventions for high grade vulval intraepithelial neoplasia (VIN). Three trials assessed topical imiquimod versus placebo, showing higher response rates with imiquimod. One trial examined low versus high dose indole-3-carbinol. Imiquimod was effective but associated with more adverse events.

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2016·Cancer prevention research (Philadelphia, Pa.)·Naomi Fujioka, Benjamin W Ransom, Steven G Carmella, et al

Harnessing the Power of Cruciferous Vegetables: Developing a Biomarker for Brassica Vegetable Consumption Using Urinary 3,3'-Diindolylmethane.

RCTn = 45

Clinical trial examining the relationship between glucobrassicin exposure from Brassica vegetables and urinary 3,3'-diindolylmethane (DIM) levels in 45 subjects. Urinary DIM excretion increased with glucobrassicin dose and plateaued between 200 and 300 μmol, indicating DIM as a reliable biomarker of glucobrassicin exposure and I3C uptake.

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2013·Cancer epidemiology, biomarkers & prevention : a publication of the American Association for Cancer Research, cosponsored by the American Society of Preventive Oncology·Naomi Fujioka, Cheryl E Ainslie-Waldman, Pramod Upadhyaya, et al

Urinary 3,3'-diindolylmethane: a biomarker of glucobrassicin exposure and indole-3-carbinol uptake in humans.

RCTn = 25

Randomized crossover trial with 25 subjects to test urinary 3,3'-diindolylmethane (DIM) as a marker of indole-3-carbinol (I3C) uptake from Brassica vegetables. Urinary DIM was significantly higher after consuming Brussels sprouts compared to cabbage, indicating successful quantification of I3C uptake.

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2006·Carcinogenesis·Jay H Fowke, Jason D Morrow, Saundra Motley, et al

Brassica vegetable consumption reduces urinary F2-isoprostane levels independent of micronutrient intake.

RCTn = 20Inflammation

This randomized crossover trial compared the effects of Brassica Vegetable intervention against Micronutrient and Fiber Supplementation on urinary F2-isoprostane levels, a biomarker of oxidative stress, in 20 participants. Brassica consumption significantly reduced F2-isoprostane levels by about 22% compared to baseline and the M+F intervention, suggesting reduced systemic oxidative stress independent of vitamin and mineral content.

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2006·Cancer epidemiology, biomarkers & prevention : a publication of the American Association for Cancer Research, cosponsored by the American Society of Preventive Oncology·Gregory A Reed, Dora W Arneson, William C Putnam, et al

Single-dose and multiple-dose administration of indole-3-carbinol to women: pharmacokinetics based on 3,3'-diindolylmethane.

RCTn = 14

Phase I trial in women studying the pharmacokinetics of indole-3-carbinol (I3C) and its condensation product 3,3'-diindolylmethane (DIM). Women received oral doses of I3C, and plasma samples were analyzed. DIM was the only detectable product, with Cmax increasing with dose up to 1,000 mg. Significant interindividual variation was observed in plasma DIM values.

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2006·International journal of gynecological cancer : official journal of the International Gynecological Cancer Society·R Naik, S Nixon, A Lopes, et al

A randomized phase II trial of indole-3-carbinol in the treatment of vulvar intraepithelial neoplasia.

RCTn = 12Womens Health

A randomized phase II trial assessed the therapeutic benefits of indole-3-carbinol (I3C) in women with high-grade vulvar intraepithelial neoplasia (VIN). Significant improvements were observed in symptomatology and vulvoscopic appearance, although no histologic improvement in VIN grade was noted. The study suggests clinical improvement with I3C therapy.

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2005·Cancer epidemiology, biomarkers & prevention : a publication of the American Association for Cancer Research, cosponsored by the American Society of Preventive Oncology·Gregory A Reed, Kirstin S Peterson, Holly J Smith, et al

A phase I study of indole-3-carbinol in women: tolerability and effects.

RCTn = 17

Phase I trial of indole-3-carbinol (I3C) in 17 women from a high-risk breast cancer cohort. Subjects ingested 400 mg I3C daily for 4 weeks followed by 800 mg daily for another 4 weeks. I3C was well tolerated, increased CYP1A2 activity, and altered hormone metabolite ratios, suggesting potential chemopreventive effects.

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2000·Gynecologic oncology·M C Bell, P Crowley-Nowick, H L Bradlow, et al

Placebo-controlled trial of indole-3-carbinol in the treatment of CIN.

RCTn = 30Womens Health

RCT of 30 patients with CIN II-III comparing placebo to 200 mg/day and 400 mg/day indole-3-carbinol (I-3-C) for 12 weeks. The I-3-C groups showed significant regression of CIN compared to placebo, with a dose-dependent change in the 2/16 alpha-hydroxyestrone ratio.

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1999·Cancer detection and prevention·E Taioli, H L Bradlow, S V Garbers, et al

Role of estradiol metabolism and CYP1A1 polymorphisms in breast cancer risk.

Case-controln = 369

The study investigates the role of estradiol metabolism and CYP1A1 polymorphisms in breast cancer risk. African-American women with the wild-type CYP1A1 gene showed a significant increase in the 2-OHE1/16-OHE1 ratio after treatment with indole-3-carbinol. The CYP1A1 Msp1 polymorphism was associated with increased breast cancer risk in African-American women.

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1997·Journal of cellular biochemistry. Supplement·G Y Wong, L Bradlow, D Sepkovic, et al

Dose-ranging study of indole-3-carbinol for breast cancer prevention.

RCTn = 60Womens Health

RCT involving 60 women at increased risk for breast cancer, testing indole-3-carbinol (I3C) for chemoprevention. The study found that a 300 mg daily dose of I3C significantly altered the urinary estrogen metabolite ratio, suggesting it as a promising chemopreventive agent for breast cancer.

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1994·Cancer epidemiology, biomarkers & prevention : a publication of the American Association for Cancer Research, cosponsored by the American Society of Preventive Oncology·H L Bradlow, J J Michnovicz, M Halper, et al

Long-term responses of women to indole-3-carbinol or a high fiber diet.

RCTn = 60Womens Health

RCT with 60 women testing the effect of 400 mg/day indole-3-carbinol (I3C) or 20 g/day alpha-cellulose on estrogen metabolite ratio over 3 months. I3C increased the 2-OH-estrone:estriol ratio, sustained over the period, while no changes were observed in the control and fiber groups.

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2024·Diseases·Kakarla Ramakrishna, Praditha Karuturi, Queen Siakabinga, et al

Indole-3 Carbinol and Diindolylmethane Mitigated β-Amyloid-Induced Neurotoxicity and Acetylcholinesterase Enzyme Activity: In Silico, In Vitro, and Network Pharmacology Study

In vitroBrain Health

The study investigated the anti-Alzheimer's disease effects of indole-3 carbinol (I3C) and diindolylmethane (DIM) using in silico, in vitro, and network pharmacology methods. I3C and DIM inhibited acetylcholinesterase activity and beta-amyloid aggregation, enhanced cell viability, and reduced ROS in SH-S5Y5 cells exposed to beta-amyloid, showing neuroprotective effects comparable to donepezil.

Semantic ScholarRead on Semantic Scholar
1999·Biochemical pharmacology·J R Cashman, Y Xiong, J Lin, et al

In vitro and in vivo inhibition of human flavin-containing monooxygenase form 3 (FMO3) in the presence of dietary indoles.

RCTn = 10

The study investigated the effect of Brussels sprouts consumption on flavin-containing monooxygenase activity in 10 healthy male volunteers. The sprouts group showed a significant increase in trimethylamine to trimethylamine N-oxide ratios, indicating decreased enzyme activity. In vitro studies suggested that indole-3-carbinol derivatives from Brussels sprouts are potent inhibitors of the enzyme.

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1998·Otolaryngology--head and neck surgery : official journal of American Academy of Otolaryngology-Head and Neck Surgery·C A Rosen, G E Woodson, J W Thompson, et al

Preliminary results of the use of indole-3-carbinol for recurrent respiratory papillomatosis.

RCTn = 18

Phase I trial of indole-3-carbinol for recurrent respiratory papillomatosis in 18 patients. 33% had cessation of papilloma growth, 33% had reduced growth rate, and 33% showed no response. Indole-3-carbinol was safe and well tolerated, with changes in estradiol hydroxylation ratios correlating with clinical response.

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1998·International journal of obesity and related metabolic disorders : journal of the International Association for the Study of Obesity·J J Michnovicz

Increased estrogen 2-hydroxylation in obese women using oral indole-3-carbinol.

RCTn = 5Womens Health

Clinical intervention study with 5 obese premenopausal women ingesting 400 mg of indole-3-carbinol for two months. The study found a significant increase in the ratio of urinary estrogens, indicating increased estrogen 2-hydroxylation, which may help reduce estrogen-dependent cancer risk.

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2004·Journal of voice : official journal of the Voice Foundation·Clark A Rosen, Paul C Bryson

Indole-3-carbinol for recurrent respiratory papillomatosis: long-term results.

Studyn = 33

Prospective, open-label study of Indole-3-Carbinol (I3C) for recurrent respiratory papillomatosis (RRP) treatment. Thirty-three patients were followed long-term, with 33% experiencing remission and 30% having reduced papillomatous growth. No worsening of RRP or side effects were reported. I3C shows promise as a treatment option for RRP.

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2001·Lupus·T E McAlindon, J Gulin, T Chen, et al

Indole-3-carbinol in women with SLE: effect on estrogen metabolism and disease activity.

Observationaln = 17Womens Health

Open-label metabolic study of 375 mg/day indole-3-carbinol (I3C) in women with SLE, followed by a 3-month observational period. The study found an increase in the 2:16alpha hydroxyestrone ratio, suggesting a shift towards less estrogenic metabolites. No significant effects on SLE disease activity were observed during the 3-month period.

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