This is gonna sound weird but...

[Emo]

Shoulders. Do they get smaller on hrt?

[piglet smith]

The muscle you have on them should shrink a bit, but the skeletal structure won't. But if you're lucky, your hips may get enough fat on them to offset the appearance of wider shoulders.

[FalseHybridPrincess]

not much my dear

of course you cant change bones but muscle loss from the arms and the back should help for them to look a little bit smaller...

[EmmaD]

As the others have said, bones aren't going to change.  Muscle and fat will diminish. 

What surprised me is while muscle loss on my shoulders has made a visible difference when looking from the front, weight loss off my upper back has really changed the side profile and changed how clothes fit.

[Ms Grace]

Like others say, skeletal structure no. The rest will depend on how bulky you were up top and why, if it's musculature from sporting activity it will eventually diminish but it may take some time. If it's fat it might redistribute a bit. I was pretty scrawny to start with but even so the upper body area has still slimmed around my shoulders and back. I find that pulling the shoulders down and back as a natural part of posture helps to visually slim them.

[Emo]

Thanks girls. This really helps.

[Just Shelly]

IDK but what I do know is that more than just a few people have told me I am petite! I myself am shocked to her this, even though I can where most petites or x-small I still do not see myself as small. Mostly because I am still a little over 5'6".

I can say for sure though that I lost much in my shoulders....it wasn't bone since this is impossible....but I guess the little muscle I did have is fairly gone now. I just wish I could see what some of these other people see!

[Christine Eryn]

My shoulder muscles have gotten really "scrawny" after a few years of HRT. I never thought it was possible, but it happened.