From the time I started HRT until reaching my lowest weight I lost about 90 lbs, and at least half of that was muscle, maybe even 60%. I was a formidable person before HRT, though my bones were always light for a 'male', they are medium-light for a woman. I can't do even a fraction of the work I used to be able to do without tiring and possibly straining my remaining muscles. I have to constantly remind myself that my body cannot do what my old memories believe it can, lol.
I have been oh HRT over 5 years, and I continue to 'down-size', even now..
For me, this is a good thing.
Missy