True to size. Material is stretchy. And the buttons do work! Lindsay is in a small. I fit a medium. I can also fit a small bit if you have a larger chest like me you’ll wanna stay true to size with medium. Holly is in the large. And Temeko is in the 3x. Hanna is wearing a 1X and feels that it runs true to size. If extra busty, you might want to consider sizing up to prevent pulling.