There are botanical books that discuss the constituents. On a Sloan Kettering website it was written as “ No single botanical or chemical extract appears responsible for the overall effects of this product. Laboratory tests have analyzed the makeup of PC-SPES and have identified estrogen-like compounds that suppress growth and proliferation of human tumor cell lines on contact, including breast, colon, and hormone-dependent and -independent prostate cancers. PC-SPES appears to interfere with the process of tumor cell division and also causes tumor cell death “
I do not see it prescribed a lot any longer due to website like ‘ quakwatch’ and others. I feel some of the ingredients are useful against cancer as Reishi and saw palmetto. Some of my patients take the ingredients of PC Spes separately and have good results. I have never seen it harm a patient .
The National Cancer Institute has this on their website “ There is evidence from both laboratory and animal studies to suggest that PC-SPES had some effect in inhibiting prostate cancer cell growth and prostate-specific antigen (PSA) expression, but it is not known whether these results were caused by adulterants such as diethylstilbestrol, which is an estrogenic compound, the herbs in PC-SPES, or their combination.There is some evidence to suggest that PC-SPES has some anticancer effects that are not related to estrogen-like activity.
Yet it is no longer made . Why ? The manufacturer is no longer in operation, and PC-SPES is no longer being made. Although there are products that claim to be substitutes for PC-SPES, they are not the patented original formulation.