This undergarment was an amazing buy. Its true to size. I ordered a small and it fit perfectly! Nice and snug. I love these pajamas and wear them all the time during the winter when its chilly! Best thing about them that when its extra chilly I can easily just throw on clothes over these and not be bothered because of stretchy/flexible these undergarments are. I can go through the whole day nice and warm! Would highly recommend! Great material! Very soft!