how many points are you putting into it? Because it definitely should be affecting the character, only reason it might not is if you have the fat/muscle ratio all the way down or if you're using a skin.
I tested it twice and put 20 points into muscle; the scale menu also doesn’t seem to work for some reason
I don’t think I’m using a skin and I’m not really sure how the fat/muscle ratio works since there’s no indication of which side is more fat and which side is more muscle
oh you're going to have to put in more than 20 for it to show for muscle, you need to hit a certain threshold for it to switch over to the muscular body type and then you will start noticing it.