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A DIM supplement contains diindolylmethane, a compound your body forms from indole-3-carbinol, which comes from cruciferous vegetables such as broccoli, cabbage and Brussels sprouts. DIM is marketed mainly around estrogen metabolism, but human research is limited: most studies are small and short, and many measure lab markers rather than health outcomes. DIM can also interact with some medicines and is not advised during pregnancy. This guide explains what DIM is, what studies have looked at, the safety and interaction facts from Memorial Sloan Kettering and the Linus Pauling Institute, who should avoid it and how to read the label.
Peptide Labs sells Biote Nutraceuticals DIM SGS+, which we describe from its label near the end. This article is general information, not medical advice.
Key Takeaways
- DIM forms in the stomach from indole-3-carbinol, released when cruciferous vegetables are chopped or chewed.
- Memorial Sloan Kettering (MSK) says clinical data on DIM are limited.
- Trials mostly measured a urinary estrogen metabolite ratio; a trial of 551 women found no effect on the cervical cell outcomes studied.
- DIM may affect liver enzymes that process drugs and lowered tamoxifen metabolite levels in one trial.
- MSK advises avoiding DIM during pregnancy, when planning pregnancy, while nursing or when using birth control pills.
What is a DIM supplement?
Cruciferous vegetables contain compounds called glucosinolates. According to the Linus Pauling Institute at Oregon State University, when raw vegetables are chopped or chewed, a plant enzyme called myrosinase converts one of them, glucobrassicin, into indole-3-carbinol (I3C). In the acid of the stomach, I3C molecules combine into several compounds, and 3,3′-diindolylmethane (DIM) is the one studied most. Researchers can even measure DIM in urine as a marker of how much of these vegetables someone ate.
DIM supplements skip that step by providing the compound directly, often in an absorption-enhanced form. Some products pair DIM with sulforaphane glucosinolate (SGS), also called glucoraphanin, a different broccoli compound that the same myrosinase enzyme, or gut bacteria, convert into sulforaphane.
DIM supplement research: what studies have looked at
MSK’s About Herbs database sums up the evidence plainly: lab studies are extensive but clinical data are limited. Human trials have been small, often short and frequently used the same branded ingredient. The main ones are summarized below.
| Study | Who and how many | What was measured | Result and limits |
|---|---|---|---|
| Thomson et al., 2017 | 130 women taking tamoxifen (98 finished), 12 months | Urinary estrogen metabolite ratio, SHBG, breast density, tamoxifen metabolites | Ratio and SHBG rose; breast density did not change; tamoxifen metabolites fell |
| Castanon et al., 2012 | 551 women with low-grade cervical cell changes, 6 months | Cervical cytology and HPV status | Well tolerated; authors said unlikely to have an effect |
| Godinez-Martinez et al., 2023 | 60 premenopausal women, 30 days | Urinary estrogen metabolite ratio | Ratio did not rise; small body fat difference was a secondary finding |
| Reed et al., 2008 | Healthy adults, single doses | Blood levels and tolerability | Mild nausea, headache and vomiting reported at the highest dose tested |
The estrogen metabolite marker
Many DIM studies track the ratio of two estrogen breakdown products in urine, 2-hydroxyestrone to 16-alpha-hydroxyestrone. A higher ratio is a change in a lab marker. It has not been shown in these trials to translate into a health outcome, and the 2023 trial in premenopausal women found no increase in the ratio at all. Its authors reported a small difference in body fat percentage as a secondary result and said more studies are needed, so it is not evidence that DIM affects weight.
What the evidence does not show
There is no reliable clinical evidence that DIM balances hormones, and MSK notes that detox claims lack scientific support. In the largest trial, 551 women with low-grade cervical cell abnormalities, the researchers concluded DIM was unlikely to affect the outcomes they measured. Words like hormone balance on a DIM label are marketing, not established findings.
Safety, side effects and interactions
In trials, DIM was generally reported as well tolerated, but side effects did appear. The Linus Pauling Institute lists gastrointestinal symptoms at high single doses, a skin rash and slight rises in the liver enzyme ALT. MSK also lists individual case reports of visual problems that resolved after stopping, a rash with a raised white blood cell count, an ischemic stroke and a blood clot in the lungs. Case reports cannot prove DIM caused these events, but they are why caution is advised.
- Drug-processing enzymes. MSK says DIM modulates several cytochrome P450 (CYP) enzymes and advises avoiding it with drugs processed by CYP450 or the MDR1 transporter, because DIM may reduce their effectiveness. The Linus Pauling Institute notes it may raise CYP1A2 activity.
- Tamoxifen. In the 2017 trial, women taking DIM had lower blood levels of endoxifen and other tamoxifen metabolites. The authors called for research on whether this weakens tamoxifen.
- Hormonal contraceptives. MSK advises people using birth control pills to avoid DIM because of its possible effects on hormone levels.
- Acid-reducing medicines. These would likely stop I3C from turning into DIM in the stomach; this matters for I3C products more than for DIM itself.
Who should avoid DIM or ask a clinician first
MSK advises avoiding DIM if you are pregnant, planning a pregnancy, nursing or using birth control pills, and the Linus Pauling Institute notes its safety in pregnancy and breastfeeding has not been established. Talk to a clinician before using DIM if you:
- Have, or have had, a hormone-sensitive condition, including hormone-sensitive cancers
- Take tamoxifen, hormone therapy or other prescription medicines
- Have liver disease or a history of blood clots, given the liver enzyme rises and case reports above
Eating cruciferous vegetables is a different matter from taking a concentrated supplement, and the safety cautions above apply to supplements.
How to read a DIM supplement label
- Milligrams of DIM per capsule. Products vary widely; compare the listed amount, not the bottle count.
- Other active ingredients. Many products add SGS, pomegranate, calcium D-glucarate, black pepper extract or vitamins. Each adds its own questions.
- Form. Crystalline or absorption-enhanced DIM describes how the ingredient is processed, not proof of effect.
- Warnings. Check pregnancy, medication and age statements.
- Claims. Promises about hormones, cancer or detox go beyond what a supplement may legally claim.
Biote Nutraceuticals DIM SGS+ label
Biote Nutraceuticals DIM SGS+ is a three-ingredient capsule from a practitioner brand. Per its label, each capsule contains:
| Ingredient | Amount per capsule |
|---|---|
| Diindolylmethane (DIM), crystalline | 150 mg |
| Pomegranate whole fruit extract | 100 mg |
| Sulforaphane glucosinolate (SGS), from broccoli seed extract | 25 mg |
The bottle holds 60 capsules and the label states it is free from soy, dairy and gluten. It advises consulting a healthcare practitioner before use if you are pregnant, nursing or trying to conceive, or if you take medication or have a medical condition. Follow the label and ask your clinician whether it is appropriate for you. It sits in our detox and cleanse category; for why cleanse claims deserve skepticism, see our liver cleanse supplements guide.
Frequently Asked Questions
What is DIM?
DIM, or diindolylmethane, is a compound formed in the stomach from indole-3-carbinol, which is released when cruciferous vegetables such as broccoli and cabbage are chopped or chewed.
What is a DIM supplement used for?
It is marketed mainly for estrogen metabolism. Small trials show it can change a urinary estrogen metabolite ratio, but clinical evidence of health benefits is limited.
Does DIM balance hormones?
That has not been shown. Studies measure changes in lab markers, and Memorial Sloan Kettering describes clinical data on DIM as limited.
What are the side effects of DIM?
Studies and case reports include nausea, headache, other digestive symptoms, rash and slight liver enzyme rises. Rare case reports describe more serious events.
Does DIM interact with medications?
It can. DIM affects enzymes that process many drugs and lowered tamoxifen metabolite levels in a trial. Ask your clinician or pharmacist before combining it with any medicine.
Can I take DIM while pregnant or on birth control?
Memorial Sloan Kettering advises avoiding DIM during pregnancy, when planning pregnancy, while nursing and when using birth control pills.
Questions about a label? Contact us or read our Buyer’s Guide. These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.
Last reviewed September 2026.
Related guides: Liver Cleanse Supplements: What Is Inside, What Research Measured and Safety Risks, Digestive Health Supplements: Fiber, Probiotics, Prebiotics and Enzymes Explained.