Fenugreek:
http://www.ncbi.nlm.nih.gov/pubmed/?term...unregulate
Shatavari:
http://www.ncbi.nlm.nih.gov/pubmed/?term...ypertrophy (does not happen in other studies to rats that aren't hormonal)
Like fenugreek, WY also has saponins and the main one in both is diosgenin. There were some GR studies too but I'd have to do some digging to find them again. And because they affect estrogen, progesterone, luteinizing hormone prolactin, insulin and testosterone in various studies, but only when already present. They might increase your own production too via increased response to luteinizing hormone. There are a lot of diabetes studies too, and anything that merely imitated insulin rather than increasing sensitivity to insulin would only cause insulin desensitivity. And all have a history of use in both genders, or I know at least FG, GR and Sv do. And unlike phytoestrogens, people tend to say that FG and PM work well together and results are even better. I also saw fewer studies on WY, so Sv, FG or (in limited amounts) GR might be a safer bet.
I think they unregulate response to hormones, so that rather than the hormone having X effect and then stopping, it has some multiple of X effect before stopping. Or they might increase your own production. Or both. All I know is in the various studies and anecdotally they seem to affect whatever you already have.
It might be related to the fact that all hormones have a similar molecular structure to each other and the saponins also have a similar molecular structure to all of them. Not enough to make a good fit into receptors that are specific to one hormone, but maybe it affects the regulation somehow. I could only guess because the studies and stories I've read don't say how, they only say what happens in the end.