Just throwing this comment up in case this drop comes up again - these run very small. I am a medium in every casual brand of shirt I own (Uniqlo, Gustin, JCrew, etc.) and the medium in this shirt is like a sausage sleeve on me. I'd estimate that it runs 1/2 to 1 full size smaller than most brands.
I'd recommend measuring yourself before buying if you haven't and if you're planning on layering or anything then definitely size up.
I'd recommend measuring yourself before buying if you haven't and if you're planning on layering or anything then definitely size up.