Diindolylmethane (DIM) is a compound created when you digest cruciferous vegetables, such as broccoli or Brussels sprouts (1, 2).

Research suggests that DIM affects estrogen levels in your body (1). 

As a result, DIM supplements have been gaining popularity as a potential treatment for a variety of hormone-related conditions, including acne, menopause symptoms, prostate issues, and certain forms of cancer. 

Still, you may wonder whether these uses are backed by scientific evidence.

This article provides a comprehensive overview of DIM supplements, including their benefits and side effects.

What are DIM supplements?

When you eat cruciferous vegetables, your stomach acid breaks down a compound called indole-3-carbinol to produce a new compound called DIM (3). 

Intriguingly, observational studies associate high cruciferous vegetable intake with a reduced risk of certain cancers, including breast and prostate cancer. While the exact mechanism is unknown, indole-3-carbinol is thought to be partly responsible (4, 5, 6). 

Although research on DIM is still quite limited, it’s thought to help balance estrogen levels in your body (1).

Specifically, DIM may stimulate the production of a less potent, more beneficial form of estrogen known as 2-hydroxyestrone (1). 

It may also help reduce the effects of a stronger form called 16 alpha-hydroxyestrone, which has been linked to weight gain and an increased risk of some cancers, including breast and uterine cancer (1, 7). 

Additionally, DIM has been shown to inhibit an enzyme called aromatase, which converts testosterone to estrogen (1). 

While cruciferous vegetables are the primary food source of DIM, you would need to eat several servings every day to reap this compound’s benefits (1). 

As a result, people looking to treat a specific condition like acne or prostate issues may seek a concentrated dose in the form of a DIM supplement. 

Summary

DIM is a compound your body makes from cruciferous vegetables. While more research is needed, it’s thought to help balance hormone levels via its effects on estrogen.

Uses and potential benefits of DIM supplements

DIM supplements are being studied for their protective effects against certain cancers. They’re also used to help prevent prostate enlargement, treat acne, aid weight loss, and reduce premenstrual syndrome (PMS) and menopause symptoms. 

While these benefits are promising, overall research on DIM’s effectiveness and long-term safety in humans is limited. 

May have anticancer effects

Test-tube and animal studies suggest that DIM supplements may help prevent the growth and spread of breast cancer cells. However, human studies are limited (1, 2).

A yearlong study gave 130 women with breast cancer on tamoxifen therapy either a placebo or 150 mg of DIM twice a day. DIM supplements resulted in a significantly improved ratio of two types of estrogen — 2-hydroxyestrone and 16-hydrozyestrone (8). 

Although research is ongoing, increasing the ratio of 2-hydrozyestrone to 16-hydrozyesterone may reduce breast cancer risk and cause anti-tumor effects (8).

A 30-day study in 19 post-menopausal women with early-stage breast cancer found that taking 108 mg of DIM per day also resulted in beneficial changes in estrogen levels (9).

Test-tube and animal studies indicate that DIM protects against ovarian, prostate, and colon cancers as well. All the same, human studies are needed (10, 11, 12).

Notably, a mouse study found that DIM helped prevent cervical cancer. However, in a 6-month study in 551 women with cervical abnormalities, taking 150 mg of DIM per day had no effect on cervical cell changes (3, 13).

May protect against prostate issues

DIM supplements may safeguard against prostate enlargement and prostate cancer. 

In fact, it may help combat prostatic intraepithelial neoplasia (PIN), a condition that’s characterized by prostate cell growth and considered to be a precursor to prostate cancer (14). 

In a 12-month study, 21 men with high-grade PIN were given either a placebo or 900 mg of DIM per day. Those given DIM experienced significant improvements in prostate health, as well as PIN (14). 

Test-tube and animal studies likewise suggest that DIM helps fight prostate cancer. Still, more human research is necessary (15).

May boost weight loss

Given that estrogen plays an important role in regulating fat accumulation, DIM supplements may aid weight loss — although no human research currently supports this effect.

All the same, studies link an imbalance of estrogen — either too much or too little — to an increased risk of weight gain in both men and women (16, 17, 18).

Furthermore, DIM supplements may stimulate fat breakdown and inhibit fat cell formation. 

In one study in mice on a high fat diet, 23 mg of DIM per pound (50 mg per kg) of body weight significantly reduced the formation of new fat cells (19).

Keep in mind that human studies are needed.

Other potential uses and benefits

DIM supplements are purported to aid other hormone-related conditions. Still, it’s important to remember that research is lacking on all of these effects.

  • May fight acne. DIM supplements are sometimes used to treat hormonal acne. However, no research currently supports this use (20, 21).
  • May reduce hot flashes. Hot flashes during menopause likely result from hormonal changes. While DIM supplements are used to reduce hot flashes, their effectiveness isn’t supported by research (22, 23).
  • May relieve PMS symptoms. PMS symptoms are thought to be due to monthly changes in estrogen levels. Again, some people use DIM supplements to reduce symptoms, but research hasn’t confirmed their effectiveness (24).
  • May correct estrogen imbalances in men. High levels of estrogen in men are linked to breast growth, erectile dysfunction, and infertility. DIM supplements may be effective but haven’t yet been studied in humans (25, 26).
Summary

Limited studies suggest that DIM supplements may help reduce prostate enlargement and protect against certain cancers. However, their effectiveness for other hormone-related conditions hasn’t been widely studied.  

Potential side effects and precautions

Due to a lack of research in humans, little is known about the long-term safety and side effects of DIM supplements. 

Current human research doesn’t show DIM supplements to be toxic or have serious side effects. The most common side effects include darkening of the urine, an increase in bowel movements, headaches, and gas (3, 8). 

Less common side effects include nausea, vomiting, diarrhea, and skin rash (3). 

As DIM supplements interact with estrogen levels, they may affect people with hormone-sensitive cancers or who are on hormone therapies. Such individuals should steer clear of DIM supplements unless under the supervision of a medical professional.

No matter your medical history, it’s important to consult your healthcare provider before taking these supplements. 

Summary

DIM supplements have not been shown to cause serious side effects, though more safety research is needed. People on hormone therapies or with certain hormone-related cancers should avoid these supplements. 

How much DIM should you take?

Due to limited research, proper dosages for DIM are unknown.

In human research, doses typically range from 108–900 mg per day — though these studies were only related to treatments for cancer and prostate enlargement (8, 9, 14).

However, a study in 24 healthy people found that although DIM doses of up to 200 mg were well tolerated and didn’t cause side effects, one person experienced nausea, headache, and vomiting after taking a 300-mg dose, suggesting that higher doses may be associated with adverse side effects (15).

Other uses of DIM supplements, such as weight loss and acne treatment, have not been studied in humans. 

Therefore, it’s best to talk to your healthcare provider to obtain personalized dosage recommendations based on your intended use. 

Summary

Due to insufficient evidence, dosage information for DIM is lacking. Before taking these supplements, get dosage guidance from your healthcare provider. 

The bottom line

DIM is a compound your body creates when you eat cruciferous vegetables. It’s also concentrated and sold as a supplement.

As it affects estrogen levels, DIM may help treat a variety of conditions, including hormone-sensitive cancers and prostate issues.

Nonetheless, further studies are needed — particularly for uses related to acne, weight loss, and PMS symptoms, which aren’t currently backed by human research.

Thus, you should talk to your healthcare provider before taking DIM supplements.

No matter DIM’s effectiveness, it’s always good to eat more cruciferous veggies. After all, vegetables like broccoli and kale are rich sources of important nutrients, including fiber, antioxidants, vitamins, and minerals.