Diindolylmethane
Useful mainly for people interested in shifting estrogen metabolite ratios; clinical benefits are not established.
Quick decision guide
May help most
People interested in shifting estrogen metabolite ratios; clinical benefits are not established
Common dosing range
100–200 mg/day, bioavailability-enhanced form
When to expect effects
Weeks to months for metabolite changes
Watch out for
Hormonal activity and CYP enzyme effects; avoid in pregnancy and with hormone-sensitive cancers without oncologist input
What is it
Diindolylmethane (3,3'-diindolylmethane, DIM) is a compound formed in the acidic environment of the stomach from indole-3-carbinol (I3C), which is present in cruciferous vegetables. It is marketed as a supplement targeting estrogen metabolism and hormonal balance.
Is it worth it for you?
Use this as a quick fit check, not a diagnosis.
Worth considering if…
Probably skip if…
Evidence at a glance
| Goal | Effect | Best fit | Time |
|---|---|---|---|
estrogen metabolism modulation Limited Evidence | Shift toward 2-hydroxyestrone | Adults wanting to alter urinary estrogen metabolite ratios | Weeks to months |
cervical dysplasia Mixed Evidence | No clear benefit | No clearly benefiting group established | Months |
estrogen metabolism modulation
- Effect
- Shift toward 2-hydroxyestrone
- Best fit
- Adults wanting to alter urinary estrogen metabolite ratios
- Time
- Weeks to months
cervical dysplasia
- Effect
- No clear benefit
- Best fit
- No clearly benefiting group established
- Time
- Months
Evidence for 2 uses
AI-assisted evidence assessment — talk to your doctor before relying on any single supplement.
estrogen metabolism modulation
Biomarker supportHuman studies show DIM increases 2-hydroxyestrone and shifts the urinary 2-hydroxyestrone to 16-alpha-hydroxyestrone ratio. This is a measurable metabolite change; it has not been shown to produce symptom relief or reduce disease risk.
Bottom line: Reliably shifts estrogen metabolite ratios, with no demonstrated clinical benefit.
cervical dysplasia
Disease adjunctSmall trials of DIM (and related indole-3-carbinol) for cervical dysplasia have produced inconsistent results, with controlled studies failing to show clear improvement in lesion regression. Evidence is insufficient to support this use.
Bottom line: Not shown to improve cervical dysplasia in controlled studies.
Evidence is mixed
Early uncontrolled reports were encouraging, but controlled trials did not confirm benefit.
How it works
How to take it
What to track
3 commercial forms
Compare the main delivery options and what they’re best suited for.
BR-DIM (BioResponse DIM)
The form used in most clinical research and the recommended option for measurable biological effects.
Phospholipid complex with significantly improved absorption compared to crystalline DIM.
Crystalline DIM
Less expensive but generally inefficient; enhanced formulations are preferable.
Very poor absorption; high doses needed for any biological effect.
DIM with absorption enhancers
Marketed for improved absorption with varying clinical evidence.
Various adjuncts like vitamin E, lecithin, or piperine added.
Safety
Know the common side effects, key cautions, and who should avoid it.
Common side effects
Who should avoid it
- Pregnant or breastfeeding people
- People with hormone-sensitive cancers (without oncologist input)
- People with liver disease (high doses)
Pregnancy & breastfeeding
Avoid in pregnancy and breastfeeding due to insufficient safety data and potential hormonal effects.
Interactions
May alter hormonal drug activity and estrogen handling
DIM can induce these enzymes and change drug levels
Protocols featuring Diindolylmethane
Evidence-backed routines where Diindolylmethane plays a role.
Food sources
| Food | Amount | %DV |
|---|---|---|
| Broccoli (1 cup cooked) | I3C precursor that converts to DIM in the stomach | — |
| Brussels sprouts (1 cup) | Among highest I3C content | — |
| Cabbage, raw (1 cup) | Significant I3C | — |
| Kale (1 cup cooked) | I3C source | — |
| Bok choy (1 cup) | I3C source | — |
Broccoli (1 cup cooked)
- Amount
- I3C precursor that converts to DIM in the stomach
- %DV
- —
Brussels sprouts (1 cup)
- Amount
- Among highest I3C content
- %DV
- —
Cabbage, raw (1 cup)
- Amount
- Significant I3C
- %DV
- —
Kale (1 cup cooked)
- Amount
- I3C source
- %DV
- —
Bok choy (1 cup)
- Amount
- I3C source
- %DV
- —
Choosing a product
What to look for on the label — and what to be skeptical of.
Look for…
Be skeptical of…
Frequently asked questions
Should I take DIM or I3C?⌄
DIM is more chemically stable and is the active form many seek. I3C converts to DIM in the stomach but also produces other compounds with variable effects. Most clinical research has shifted toward DIM.
How long until DIM affects my hormones?⌄
Measurable shifts in estrogen metabolite ratios appear within 4-8 weeks of consistent supplementation. Symptom changes, if any, may take longer.
Is bright orange urine on DIM normal?⌄
Yes, this is a common and harmless effect. It indicates the supplement is being absorbed and metabolized.
Can men take DIM?⌄
Yes. Men also benefit from healthy estrogen metabolism. DIM is sometimes used for men with hormonal concerns, though evidence is limited.
Does DIM interact with birth control?⌄
DIM may affect estrogen metabolism and CYP enzymes that metabolize hormonal contraceptives. Consult your clinician about potential interactions.
References by claim
Track Diindolylmethane with Pilora
Set up dose reminders, check interactions, and join the community in the Pilora iPhone app.
Coming to App StoreDisclaimer: These statements have not been evaluated by the FDA. This page is educational, not a substitute for personalized medical advice. Evidence grades are AI-assisted assessments — talk to your doctor before starting any new supplement, especially if you’re pregnant, breastfeeding, on medications, or managing a chronic condition.