I've looked into it and got some. Dim seem to regulate oestrogen rather than increasing it. During perimenopause, symptoms can be due to the unbalance of oestrogen, ie. Flux of it followed by sudden drop rather than just the drop after the full on menopause, in which case DIM might help.
I ha e t taken it as ultimately, we don't know much about it. It is given to some women, especially in the States I believe after breast cancer where hormones have been a factor but that's a hump to thinking that it is safe for anyone.