Copying from megathread:
Looking at the estrogen thing, I can sort of believe that it's a joke.
They mention Louis taking a bunch of pills (ie, not being secretly drugged):
Then the bit about "fucking up his brain chemistry" comes out of nowhere, and may simply have to do with how much they fuck with him:
Then, only later do the two of them talk about putting estrogen in his drinks:
I think that Bella may have given him some estrogen pills and he may have taken them willingly (since he seems to do whatever she tells him to do). The drugging him in secret bit, however, I'm not sure about. They mention hiding it in his protein powder, then mention he doesn't work out anymore so they mention possibly putting it in his drink. No telling whether they actually did it or not.