LaurenZz - 6 months ago, Verified purchaser
I bought one and since then I've bought two other colors - they are so soft it's hard to take off! I know this is technically a 'sleep t-shirt' but I wear these as workout tops as well. I'm 130lbs 5'6, I typically wear smalls but I got a XS and it still had a little room. So I would say from my experience to go a size down, and it will still be plenty loose for sleeping.