Are these things like skin tight anyone know?
https://store.liverpoolfc.com/lfc-mens-red-marl-midlayer-18-19/
This is not much to go on, I know, but I saw that in the club shop yesterday. On the dummy in the window it looked a pretty tight fit. It didn't look to be designed as a loose fit.
As JasonF said, it's not as tight as a base layer, though.
I tried on the red marl t-shirt in the range and it was quite tight for my size. Mind you, these things look great on athletes and sculptured dummies in shops, but the middle-aged and/or unfit body doesn't quite fit in them the same.
When I'm in decent shape I'm in a Large. Not in decent shape and it's an XL, but for the red marl tee to look ok I would have needed an XXL.
Not sure if any of this helps, but there you go.