Diindolylmethane (DIM) is produced when the substance ]]>indole-3-carbinol]]> (I3C) is digested. Indole-3-carbinol, found in broccoli and other vegetables, has shown considerable promise for ]]>cancer prevention]]> . Some of its benefits in this regard may occur after it is converted by the body to DIM.

DIM also has complex interactions with the hormone estrogen, which could lead to either positive or negative effects on cancer risk.



There is no dietary requirement for DIM. Good natural sources include broccoli, Brussels sprouts, cabbage, and cauliflower.

Therapeutic Dosages

Manufacturers selling DIM products typically recommend about 500 to 1,000 mg daily. The optimal dose (if there is any) is not known.

Therapeutic Uses

Numerous test-tube]]> and ]]>animal studies]]> hint that DIM is might help prevent various types of cancer, especially breast, cervical, prostate, and uterine cancer. ]]>1-16]]>

However, this evidence is far too preliminary to serve as the basis for recommending that anyone use DIM. As with many proposed cancer-preventing substances, there are also circumstances in which DIM might actually increase the risk of cancer. ]]>17-19]]>

Some of DIM’s apparent anticancer benefits appear to derive from its complex interactions with estrogen. ]]>20-27]]>

DIM appears to alter liver function in such a manner that an increased amount of estrogen becomes metabolized into inactive forms. In addition, DIN blocks certain effects of estrogen on cells; however, it may enhance other effects of estrogen. The overall effect is far too complex and poorly understood to be described as “balancing estrogen in the body,” which is what many websites say about DIM.

DIM also appears to have an anti-testosterone effect, which could make it helpful for preventing or treating breast cancer. ]]>28]]> Again, on some websites this effect has been over-optimistically termed “balancing testosterone levels.”

Highly preliminary evidence hints that DIM may offer benefit for diseases caused by human papilloma virus (HPV). These include ]]>cervical dysplasia]]> and respiratory papillomatosis. ]]>29,30]]>

According to some manufacturers, DIM can enhance ]]>sexual function]]> in men or ]]>women]]> , and also ]]>enhance sports performance]]> . However, there is no evidence that it actually works.


Safety Issues

DIM is thought to be a relatively nontoxic substance. However, comprehensive safety studies have not been completed. Due to DIM’s complex interactions with estrogen and testosterone, it has the potential for causing hormonal disturbances. Safety in young children, pregnant or nursing women, or people with severe liver or kidney disease has not been established.

Although there are no known drug interactions with DIM, the substance has shown considerable potential for interacting with many medications. 31-33]]>

For this reason, we recommend that if you use any medication that is critical for your health, do not use DIM except under a physician's supervision.