Are there medicines/creams that target specific areas of the body in transition? For example, a cream to slow down breast growth when taking oestrogen?

Unfortunately, we are unaware of any medicine with such characteristics. All human cells contain hormone receptors accounting for the ‘full body’ response people have when taking hormones. The effectiveness of hormones varies from person to person due to a variety of factors including genetics and even the environment in which you live.

We know that some patients find the change in breast size distressing. If it is of concern, once your hormone levels are constant and your body transition has stabilized, you may wish to consider plastic surgery to shape your breasts in the way that makes you most comfortable.