Exerpt from article on mast…
DHT directly inhibits estrogenic activity on tissues. It is possible that it does this, possibly by acting as a competitive antagonist to the estrogen receptor or by decreasing estrogen receptor binding. Either way, it has multiple hypothesized mechanisms of action in some tissues. It has also been hypothesized that DHT actually suppresses estrogen’s effects not by inhibition of synthesis of estrogen receptor, but by (get ready…big words coming up) decreasing estrogen-induced RNA transcription at some point after the actual estrogen receptor binding has occurred. This means, in much simpler terms, that the estrogen gets to the receptor, but just doesn’t do its job…
Seems as if there isn’t a unified theory on the way mast works to block estrogen. However in past breast cancer treatment (original use for mast) studies had patients on mast n nolvadex. It would therefore lead me to believe it either has no negative affect on Ralox (being fairly similar to nolva) or it would in fact increase its effectivness.