It takes time but it happens. If you are already heavily muscled it may take some particularly specific exercise to burn the muscle off (I think people refer to cardio, hopefully someone who knows more will respond) and a change in diet to less red meat protein (most people eat too much anyway). I was pretty scrawny to begin with so didn't have much muscle to lose in the first place, except maybe my upper arms a bit and despite being on HRT over a year now that hasn't changed an awful lot.
