This s a good quality shirt and very soft. I sized up to a medium after reading reviews. It was still a little tight thru the bust and I am pretty small busted (size 36B). It was fine to wear underneath something which was my plan for it. But I would probably never wear this alone due to the tightness thru the chest area.
Addendum: This company contacted me less than 24 hours after my review posted wanted to offer me another product or way to fix my being not totally satisfied with the product. Wow! They take their customer service seriously and want their customers satisfied! As I told them, I am satisfied with the product as it was good quality and served the purpose I had for it. In fact I will probably order more. Just appreciated honest reviews of the product running on the small side and that helped me to "size up". I would recommend anyone else doing that too.