Diindolylmethane (DIM)
Research reviewed: Up until 03/2026
Diindolylmethane (DIM) (3,3'-Diindolylmethane) is a dietary supplement with 11 published peer-reviewed studies involving 29,479 participants, researched for Oestrogen Metabolism, Prostate Health, Breast Cancer Prevention and 2 more areas.
Evidence at a Glance
Strength is scored by study design, sample size, study type, and outcomes
Oestrogen Metabolism
ModerateProstate Health
ModerateBreast Cancer Prevention
ModerateImmune Modulation & Reviews
WeakClinical trials
ModerateResearch Visualised
Visual breakdown of the clinical data.
Study Quality Breakdown
What types of studies were conducted
Participants Per Study
Larger samples = more reliable results
Research Timeline
When the studies were published
All Studies
Detailed breakdown of each trial. Click to expand.
Oestrogen Metabolism
To evaluate bioavailable DIM (BR-DIM) supplementation on oestrogen metabolites in healthy post-menopausal women.
Study Type
RCT
Purpose
To evaluate bioavailable DIM (BR-DIM) supplementation on oestrogen metabolites in healthy post-menopausal women.
Dose
108 mg BR-DIM daily
Participants
40 post-menopausal women
Duration
4 weeks
Results
BR-DIM significantly increased urinary 2-OHE1:16alpha-OHE1 ratio; favourable shift toward less genotoxic oestrogen pathway.
How They Measured It
Urinary 2-OHE1:16alpha-OHE1 ratio by LC-MS/MS
To determine the optimal DIM dose for modulating oestrogen metabolism in breast cancer patients on tamoxifen.
Study Type
Dose-finding RCT
Purpose
To determine the optimal DIM dose for modulating oestrogen metabolism in breast cancer patients on tamoxifen.
Dose
75, 150, or 225 mg DIM daily
Participants
60 post-menopausal women with oestrogen-receptor positive breast cancer
Duration
12 weeks
Results
150 mg/day produced the most favourable oestrogen metabolite profile; no adverse interaction with tamoxifen pharmacokinetics.
How They Measured It
Urinary oestrogen metabolite ratios; plasma DIM levels
Prostate Health
To evaluate BR-DIM supplementation in men with rising PSA after primary prostate cancer treatment.
Study Type
Phase II RCT
Purpose
To evaluate BR-DIM supplementation in men with rising PSA after primary prostate cancer treatment.
Dose
900 mg BR-DIM daily
Participants
90 men with biochemical recurrence after prostatectomy/radiation
Duration
12 months
Results
Significant stabilisation of PSA velocity in 74% of patients; PSA doubling time lengthened; well tolerated.
How They Measured It
PSA kinetics (PSA slope, PSA doubling time), serum DIM
To investigate DIM's anti-androgenic and pro-apoptotic effects in prostate cancer cells.
Study Type
Mechanistic in vitro study
Purpose
To investigate DIM's anti-androgenic and pro-apoptotic effects in prostate cancer cells.
Dose
10-50 µM DIM
Participants
LNCaP and DU145 prostate cancer cell lines
Duration
48 hours
Results
DIM inhibited androgen receptor activation, suppressed AR target gene expression, and induced apoptosis in both androgen-sensitive and resistant lines.
How They Measured It
Androgen receptor transcriptional activity; cell viability; caspase activation
Breast Cancer Prevention
To evaluate DIM supplementation in women with hormone receptor positive breast cancer on aromatase inhibitors.
Study Type
Phase II trial
Purpose
To evaluate DIM supplementation in women with hormone receptor positive breast cancer on aromatase inhibitors.
Dose
150 mg DIM daily
Participants
120 women with breast cancer on AI therapy
Duration
6 months
Results
DIM significantly improved urinary oestrogen metabolite profiles; no significant change in BMD; well tolerated.
How They Measured It
Urinary oestrogen metabolites, bone mineral density, quality of life
To assess DIM chemoprevention of mammary cancer in a carcinogen-induced model.
Study Type
Animal study
Purpose
To assess DIM chemoprevention of mammary cancer in a carcinogen-induced model.
Dose
10 mg/kg DIM orally
Participants
Rodent DMBA-induced mammary cancer model
Duration
16 weeks
Results
DIM significantly reduced mammary tumour incidence (−60%) and multiplicity; anti-oestrogenic and anti-proliferative mechanisms confirmed.
How They Measured It
Tumour incidence, multiplicity, oestrogen receptor expression
Immune Modulation & Reviews
To investigate DIM's effects on immune cell activation and cytokine production.
Study Type
In vitro immune study
Purpose
To investigate DIM's effects on immune cell activation and cytokine production.
Dose
1-20 µM DIM
Participants
Human PBMC and dendritic cell cultures
Duration
48-72 hours
Results
DIM modulated dendritic cell function, promoted Th1-skewing, and suppressed NF-kB-mediated pro-inflammatory cytokine release.
How They Measured It
Dendritic cell maturation markers, Th1/Th2 cytokine balance, NF-kB activity
To assess safety, tolerability and pharmacokinetics of oral DIM in healthy volunteers.
Study Type
Phase I safety study
Purpose
To assess safety, tolerability and pharmacokinetics of oral DIM in healthy volunteers.
Dose
100-400 mg DIM daily
Participants
24 healthy volunteers
Duration
4 weeks
Results
DIM was well tolerated at all doses; peak plasma levels achieved at 2-4 hours; t1/2 ~8 hours; no significant safety concerns.
How They Measured It
Serial plasma DIM levels by HPLC; adverse events; liver function tests
To comprehensively review the clinical and pre-clinical evidence for DIM in cancer prevention.
Study Type
Systematic review
Purpose
To comprehensively review the clinical and pre-clinical evidence for DIM in cancer prevention.
Dose
Various doses reviewed
Participants
Multiple studies reviewed
Duration
Review
Results
DIM has consistent in vitro anti-cancer activity; clinical trials show favourable oestrogen metabolism effects and prostate cancer PSA stabilisation; safety is well established.
How They Measured It
Systematic literature review
To explore intake of DIM precursors (crucifer vegetables) and prostate cancer risk.
Study Type
Observational study
Purpose
To explore intake of DIM precursors (crucifer vegetables) and prostate cancer risk.
Dose
Dietary crucifer intake (observational)
Participants
29,000 men in prospective cohort
Duration
10 years follow-up
Results
High cruciferous vegetable intake associated with 11% reduced prostate cancer risk; strongest effect for advanced stage disease.
How They Measured It
FFQ dietary assessment; prostate cancer incidence from registry
Clinical trials
To examine the effect of DIM supplementation on benzo[a]pyrene toxicokinetics in humans.
Study Type
Randomized, open-label, crossover
Purpose
To examine the effect of DIM supplementation on benzo[a]pyrene toxicokinetics in humans.
Dose
300 mg/day BR-DIM for 7 days
Participants
Healthy adults (small n)
Duration
7 days supplementation prior to micro-dose challenge
Results
DIM markedly increased Tmax and reduced Cmax for BaP, reduced total [14C] recovered from plasma by 56-67%, suggesting slower absorption and altered detoxification of the carcinogen.
How They Measured It
UPLC-accelerator mass spectrometry of [14C]-BaP and metabolites in plasma
Frequently Asked Questions
Common questions about Diindolylmethane (DIM) research
There are currently 11 peer-reviewed studies on Diindolylmethane (DIM) (3,3'-Diindolylmethane), involving 29,479 total participants. Research covers Cancer prevention, Oestrogen balance, Prostate health and 1 more areas. The overall evidence strength is rated as Moderate.
The evidence is currently rated as "Moderate Evidence". This rating is based on study design quality (randomisation, blinding, placebo controls), sample sizes, study types (7 human studies), and reported outcomes.
Diindolylmethane (DIM) has been researched for: Cancer prevention, Oestrogen balance, Prostate health, Immune support. Each area has its own body of evidence which you can explore in the study breakdowns above.
Yes, 7 out of 11 studies are human trials. Human trials carry more weight in our evidence scoring system.
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