Your frame is generally more reliant upon genetics than hormones. Hormones have an influence in women because they need to be able to give birth, but that's primarily around the hips. I've seen cis-women who have large frames and cis-men who have small frames, though generally it's the other way around.

My frame's not really been an issue for me and I've never taken hormones. It's not great, but it's not terrible either — and that's all up to genetics.

If someone under 18 needs treatment for non-transitional purposes that's entirely fine, btw. It's just when you want to counter your natural development when it needs to wait.