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Isolated phytochemicals & plant compounds

3,3'-Diindolylmethane

3,3'-Diindolylmethane

3,3'-Diindolylmethane (DIM) is an indole compound formed from indole-3-carbinol in cruciferous vegetables and sold as a supplement. Human research has found changes in hormone-metabolism biomarkers, not established health outcomes; compare the exact formulation and labeled DIM amount, and note the documented tamoxifen interaction.

Isolated CompoundFood DerivedClinical ResearchMixed EvidenceForm Dependent EvidenceLow Risk ProfileMedication Interaction Risk
Updated August 2026/4 min read/7 citations
Reviewed by the NootropicsIndex editorial team.Method: prioritize cited human research and official safety or regulatory sources; compare retailer-listed prices without endorsing products.Affiliate disclosure
Extra caution

Who should avoid this or get expert review first

This is not a recommendation to use. These groups should treat the profile as a reason to slow down and verify safety, rules, and personal context.

  • People taking tamoxifen3Do not assume DIM can be combined with tamoxifen: a 12-month randomized trial found lower endoxifen and other tamoxifen metabolites in the DIM group. Medication decisions should be evaluated by the clinician or pharmacist overseeing tamoxifen.
01

What is it?

What DIM is

3

DIM is an indole compound related to indole-3-carbinol from cruciferous vegetables. In human trials it changed hormone-metabolism biomarkers; those changes do not establish a health outcome.

Evidence in context4
A six-month randomized trial did not show a clear benefit on the clinical outcomes it assessed. DIM should not be presented as having an established outcome benefit on the basis of biomarker or laboratory findings.
02

Names, aliases and forms

AbbreviationDIM
Chemical NameDiindolylmethane
Cas Number1968-05-4
03

Mechanisms of action

Metabolism and mechanism research

5

Human pharmacokinetic work found parent DIM plus hydroxylated, sulfate, and glucuronide metabolites after oral use. Mechanistic activity of DIM or its metabolites does not by itself establish a supplement benefit.

04

Potential effects and evidence map

Human trials report hormone-metabolism biomarker changes, while controlled clinical-outcome evidence remains limited or negative. Results from absorption-enhanced DIM formulations may not transfer to every powder or capsule.

Effect domainMagnitudeGrade
Libido / vitality3
UnknownConfidence: High

No established libido or vitality benefit from human DIM trials.

Note Human DIM research has focused on hormone-metabolism biomarkers rather than this consumer-facing outcome.

0/5
C
05

Typical dosages and timing

Typical
150-300 mg/day
Not a recommendation
Lower bound
150 mg/day
Profile value
Upper bound
300 mg/day
Profile value
Human trial range3150-300 mg/day

The cited controlled trials used absorption-enhanced BioResponse DIM for six months or twelve months. These trial designs inform the dose range above, not personal use.

06

Timing & effect horizon

Effect horizonUnknown
Unknown
Peak5Acute
2.7 h
Half-life5Acute
4.3 h
Study window4Cumulative
6 months
Study window3Cumulative
12 months
Pharmacokinetic context5

In a small study using an absorption-enhanced product, mean peak parent DIM concentration was about 2.7 hours and mean parent The time for blood levels to fall by half during the final elimination phase.Source about 4.3 hours after one week of use. Concentrations and metabolism varied substantially; these data do not establish subjective effect duration.

07

Safety, side effects and risk profile

GI discomfort2
Confidence: Medium

Nausea, headache, and vomiting occurred in a small single-dose study at 300 mg of an absorption-enhanced product.

Note The evidence is small and formulation-specific; most single doses up to 200 mg were reported as well tolerated.

1/5
B
Interaction risk3
Confidence: High

DIM reduced plasma tamoxifen metabolites, including endoxifen, in a 12-month randomized trial.

Note This is a material medication-specific concern; it does not quantify interactions with every medicine.

3/5
B
Evidence uncertainty4
Confidence: High

Long-term safety and clinically meaningful benefit are not established across ordinary retail formulations.

Note Available human trials use selected populations and absorption-enhanced products.

2/5
C
Tolerability2

In a small single-dose study of absorption-enhanced DIM, no product-related adverse effects were reported through 200 mg. At 300 mg, mild nausea and headache were reported and one participant also reported vomiting considered probably related.

08

Interactions and cautions

Other medication interactions6

Cell studies indicate DIM can induce PXR-regulated CYP3A4 and MDR1 expression. This is a mechanistic signal, not a quantified human interaction for every medicine; interaction potential outside tamoxifen remains uncertain.

09

Legal and regulatory status

United States dietary-supplement context7

As of 2026, FDA does not approve dietary supplements for safety and effectiveness before marketing. DIM product claims and legal compliance are product- and manufacturer-specific in the United States.

10

Practical buying and quality notes

  • Compare the labeled DIM amount per serving and the formulation before comparing normalized price. The human pharmacokinetic and controlled-trial evidence on this page used absorption-enhanced BioResponse DIM, so milligram labels on generic powders or capsules are not automatically equivalent.2
11

FAQ

What DIM amount has been studied?

3

The cited controlled trials used absorption-enhanced DIM. Compare this formulation-specific research context with the amount and form printed on a product label; it is not a universal use instruction.

Does a study length establish a DIM cycle?

4

No. Six- and twelve-month periods describe the trial windows cited here, not an established effect duration or a recommended cycle.

12

References

  1. FDA Global Substance Registration System (GSRS): 3,3'-Diindolylmethane (UNII SSZ9HQT61Z).
  2. Reed GA, et al. Single-dose pharmacokinetics and tolerability of absorption-enhanced 3,3'-diindolylmethane in healthy subjects. Cancer Epidemiol Biomarkers Prev. 2008;17(10):2619-2624.
  3. Thomson CA, et al. A randomized, placebo-controlled trial of diindolylmethane for breast cancer biomarker modulation in patients taking tamoxifen. Breast Cancer Res Treat. 2017;165(1):97-107.
  4. Castañon A, et al. Effect of diindolylmethane supplementation on low-grade cervical cytological abnormalities: double-blind, randomised, controlled trial. Br J Cancer. 2012;106(1):45-52.
  5. Vermillion Maier ML, et al. 3,3'-Diindolylmethane Exhibits Significant Metabolism after Oral Dosing in Humans. Drug Metab Dispos. 2021;49(8):694-705.
  6. Pondugula SR, et al. Diindolylmethane, a naturally occurring compound, induces CYP3A4 and MDR1 gene expression by activating human PXR. Toxicol Lett. 2015.
  7. U.S. Food and Drug Administration. Is It Really 'FDA Approved'? Dietary supplements section.
Note

This page is informational and summarizes available evidence. It is not medical advice, a recommendation, or a substitute for guidance from a qualified clinician.