I order a size up because I wanted a looser fit to workout in. It’s not that loose if I order a medium it just would have been slightly fitted. But the design and quality of these shirts are really good I bought green red and white. White and green are my most worn though. They can be perfectly paired with a racer back sports bra. I don’t see any sweat stains on them either after I work out. If you want slightly more room size up or if you like a fitted look order your normal size. I’m 5’2” and curvy. I will go back and buy more of these it’s a closet essential.