The shirt has a nicely tailored shape for a thin torso. Medium fits a 6'1" 160 pound frame well. The size guide suggests a Medium has a 40 inch chest, and I have a 41 inch chest, so I almost got the large, but was glad I got the medium -- there is still enough room in the chest to move comfortably.The fabric is very thin, which works for me because I am wearing it to an event in Miami in July. But, yes, you can see my pink skin tone through the shirt in bright light. Don't expect this shirt to obscure any embarrassing tattoos. Fabric feels quite breathable and the tag says 70% cotton, 25% nylon and 5% elastan. Fabric does not feel stretchy.My son asked me, "why does my skin look so pink through this shirt?" The truth is that it is paper thin. He told me, "This shirt is way too flimsy. It's like paper or something."Odd that this level of quality should be a Calvin Klein product. We are used to much higher quality than this from CK; we'd thought we could safely order online based on the brand. We have five males in this household; we haven't come across as thin a shirt fabric as this in anyone's wardrobe.Fit was rather nice, though. My sons like athletic slim fit, and it is.Returned.