Calcium D Glucarate

Is anyone taking Calcium D Glucarate with milk thistle?  Was suggested Thorne brand but can't get without milk thistle in Canada. My ND encourages me to take at least 1000 mg a day, claims it helps bind and decrease estrogen.  Concerned about the milk thistle as the pharmacy at the cancer clinic said to stay away from milk thistle as has estrogenic qualities - ND said it is safe????  Am taking only 10 mg of tamoxifen, cannot handle the 20 mg - side effects too nasty, so hoping the calcium d glucarate would be beneficial.  Any bit of knowledge or opinions would be appreciated.

Thanks ladies....