I buy 2 or 3 of these every year, usually in the sale as a bit pricey at full price. I am a 10-12 but the regular XS is a perfect fit, with good sleeve length. The crew neck version is a much better fit than the scoop neck. They give a smooth outline and are perfect under fine knitwear or blouses for a extra warmth. I note that these and the short sleeve version are not available for the current season. I do hope that you will continue to sell these, as I struggle to find great fitting base layers. The cotton tops are always too baggy, even in the XS size, and the modal content makes laundering these tops a doddle .