NutriDex

The Supplement Research Compendium
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DIM (Diindolylmethane)

Broccoli-derived compound marketed to shift estrogen metabolism.

Mixed evidence ⏳Longevity✨Joint & Skin

✚ Updated · How we grade evidence

Evidence tier
Mixed
Research weight
Citations
7 verified / 7
Classification
Longevity
❝
What the evidence says. Graded mixed: DIM reliably nudges the 2/16-hydroxyestrone ratio, but trials testing whether that translates into clinical benefit are largely null — it did not change cervical cytology or HPV clearance, and the popular acne, weight and 'estrogen detox' claims have no controlled human evidence. (Mixed evidence: Conflicting results across studies; benefit uncertain.)

What is DIM (Diindolylmethane)?

DIM (Diindolylmethane) is a longevity supplement used for shift estrogen metabolite ratio. NutriDex grades the human evidence as Mixed. DIM is a compound your gut forms from indole-3-carbinol in broccoli and other cruciferous vegetables. Small human trials consistently show it raises the urinary 2-hydroxyestrone to 16-alpha-hydroxyestrone ratio and serum SHBG — a biomarker shift, not a proven health outcome. Where outcomes were measured, results disappoint: a 551-woman RCT found 150 mg/day did not improve low-grade cervical abnormalities or clear HPV, and a 1-year BRCA-carrier study found only a tiny drop in breast density. Cervical suppository and prostate trials were small and need replication. There are no controlled trials supporting the common marketing claims for acne, fat loss, menopause or 'hormone balancing'. In women on tamoxifen, DIM lowered active drug levels, which is a concern. Overall it is biologically active but clinically unproven for the things people buy it for.

Purported Benefits

✓Shift estrogen metabolite ratio
✓Hormonal acne (claimed)
✓Cruciferous-vegetable extract
✓Investigational cancer biomarker tool

Evidence by outcome

The same supplement can be well-proven for one use and unproven for another — here is the human evidence graded outcome by outcome.

OutcomeEvidenceEffectStudies
Shift estrogen metabolite ratio / raise SHBGTrials consistently raise 2/16-OHE1 ratio and SHBG, but this is a biomarker shift, not a proven health outcome. Moderate ↑ benefit · moderate 2
Improve/clear low-grade cervical abnormalities (HPV)Large RCT (n=551) of 150 mg/day for 6 mo did not improve cervical cytology or clear HPV. Moderate — no effect · negligible 1
Reduce breast density in BRCA carriers1-year trial (n=23) showed only a tiny drop in fibroglandular tissue score; clinically trivial. Preliminary ↔ mixed · negligible 1
Cervical/prostate intraepithelial neoplasia regressionSmall suppository (n=78) and prostate (n=21) trials suggest regression but are tiny interim analyses needing replication. Preliminary ↑ benefit 2
Hormonal acne / fat loss / 'hormone balancing'No controlled trials support these common marketing claims; entirely unproven. No Evidence — no effect
Lowers active tamoxifen (endoxifen) levelsRCT found DIM reduced active tamoxifen metabolite levels, a potential drug-interaction concern. Preliminary ⚠ risk · moderate 1

Dosing & Compounds

Typical Dose
Most trials used 100–150 mg/day of an absorption-enhanced formulation (BioResponse-DIM); cancer studies have gone up to 900 mg/day.
Active Compounds
3,3'-Diindolylmethane (DIM)Indole-3-carbinol (dietary precursor)

Safety & Cautions

Generally well tolerated short-term; the most common effect is harmless dark/amber urine, plus occasional nausea, headache or GI upset (more frequent above ~200 mg). DIM induces and competes for CYP450 enzymes, so it can lower levels of drugs cleared this way — notably it reduced active tamoxifen (endoxifen) metabolites in an RCT, and asymptomatic hyponatremia has been reported when high-dose DIM was combined with sodium-depleting diuretics. Because it alters estrogen and androgen signalling, avoid in pregnancy and breastfeeding and use caution with hormone therapy, hormone-sensitive cancers and any CYP-metabolised medication. Educational only — always check with your doctor or pharmacist before combining DIM (Diindolylmethane) with any medicine.

Key Studies

Systematic review Amare 2020 ✓ Full text
Systematic review of 22 human trials: DIM consistently alters estrogen metabolism and hormone biomarkers, but clinical anti-cancer efficacy remains unproven.
RCT Yerushalmi 2020 ✓ PubMed
Prospective trial (n=23 BRCA carriers): 100mg/day for 1yr produced a small decrease in mammographic fibroglandular tissue score (2.8 to 2.65, p=0.031).
RCT Thomson 2017 ✓ PubMed
RCT (n=130) of 150mg BID for 12mo raised 2/16-OHE1 ratio and SHBG but lowered tamoxifen metabolite (endoxifen) levels.
RCT Ashrafian 2015 ✓ PubMed
Phase IIa RCT (n=78): DIM vaginal suppositories (100–200mg/day) gave higher complete CIN regression vs placebo (~90–100% vs 61%).
RCT Paltsev 2016 ✓ PubMed
Small RCT (n=21): 900mg/day DIM gave complete prostatic intraepithelial neoplasia regression in 45.5% vs 0% placebo (interim analysis).
RCT Castañon 2012 ✓ PubMed
RCT (n=551): 150mg/day for 6mo did not improve low-grade cervical cytology or clear HPV (CIN2+ 8.8% DIM vs 12.4% placebo, NS).
Safety Reed 2008 ✓ PubMed
Single-dose PK/safety study: absorption-enhanced DIM tolerated up to 200mg; nausea/headache/vomiting reported at 300mg.
7 sources cited · 7 verified Search all studies on PubMed ↗

Common questions about DIM (Diindolylmethane)

What is DIM (Diindolylmethane) used for?

DIM (Diindolylmethane) is most often taken for Shift estrogen metabolite ratio, Hormonal acne (claimed), Cruciferous-vegetable extract, Investigational cancer biomarker tool. Broccoli-derived compound marketed to shift estrogen metabolism.

Does DIM (Diindolylmethane) work — what does the evidence say?

Mixed evidence. Conflicting results across studies; benefit uncertain. DIM is a compound your gut forms from indole-3-carbinol in broccoli and other cruciferous vegetables. Small human trials consistently show it raises the urinary 2-hydroxyestrone to 16-alpha-hydroxyestrone ratio and serum SHBG — a biomarker shift, not a proven health outcome. Where outcomes were measured, results disappoint: a 551-woman RCT found 150 mg/day did not improve low-grade cervical abnormalities or clear HPV, and a 1-year BRCA-carrier study found only a tiny drop in breast density. Cervical suppository and prostate trials were small and need replication. There are no controlled trials supporting the common marketing claims for acne, fat loss, menopause or 'hormone balancing'. In women on tamoxifen, DIM lowered active drug levels, which is a concern. Overall it is biologically active but clinically unproven for the things people buy it for.

What is the typical dose of DIM (Diindolylmethane)?

Most trials used 100–150 mg/day of an absorption-enhanced formulation (BioResponse-DIM); cancer studies have gone up to 900 mg/day.

Is DIM (Diindolylmethane) safe? Any cautions or side effects?

Generally well tolerated short-term; the most common effect is harmless dark/amber urine, plus occasional nausea, headache or GI upset (more frequent above ~200 mg). DIM induces and competes for CYP450 enzymes, so it can lower levels of drugs cleared this way — notably it reduced active tamoxifen (endoxifen) metabolites in an RCT, and asymptomatic hyponatremia has been reported when high-dose DIM was combined with sodium-depleting diuretics. Because it alters estrogen and androgen signalling, avoid in pregnancy and breastfeeding and use caution with hormone therapy, hormone-sensitive cancers and any CYP-metabolised medication.

How many studies support DIM (Diindolylmethane)?

NutriDex cites 7 sources for DIM (Diindolylmethane), graded "Mixed".

Cite this page
APA

Peh, D. (2026). DIM (Diindolylmethane): Benefits, Dosage, Side Effects & Evidence. NutriDex — The Supplement Research Compendium. Retrieved 26 Jun 2026, from https://nutridex.info/s/dim

BibTeX
@misc{nutridex_dim,
  author       = {Peh, Daryl},
  title        = {DIM (Diindolylmethane): Benefits, Dosage, Side Effects \& Evidence},
  year         = {2026},
  howpublished = {NutriDex --- The Supplement Research Compendium},
  url          = {https://nutridex.info/s/dim},
  note         = {Reviewed by Dr Daryl Peh, MBBS Singapore, MMed FM. Accessed 2026-06-26}
}

For medical claims, citing the underlying primary studies linked above is preferred. NutriDex is an educational reference, not medical advice.

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