Diindolylmethane is formed when indole-3-carbinol (I3C) is digested in the stomach. It is thought that I3C affects the metabolism (breakdown) of estrogen hormones in the body, increasing the levels of certain "good" estrogen compounds while decreasing the levels of "bad" estrogens. Also, I3C may act as an anti-estrogen and may inhibit the growth of certain types of cancer cells. It is likely that I3C also works in several other ways that are not fully understood.
It is often claimed that diindolylmethane works just like I3C, although research suggests that there may be important differences between the two compounds. For instance, some studies have suggested that diindolylmethane may have different effects on estrogen metabolism compared to I3C and that diindolylmethane may have both anti-estrogen and estrogen-like activity. Currently, there is much debate (mostly among manufacturers and patent holders of various diindolylmethane and I3C products) about which compound is best and whether diindolylmethane provides the same benefits as I3C.
There is not enough evidence to know for sure if diindolylmethane really works for any use (see Does DIM Work? for more information).
A safe and effective dose for diindolylmethane has not yet been established.
(Click Diindolylmethane Dosage for more information.)
Diindolylmethane may potentially interact with some medications (see Drug Interactions With Diindolylmethane).