I bought a few of these to use after undergoing a biopsyand have to sleep in a bra for awhile, which is something that I never do because bras irritate me while sleeping.  I have been sleeping in these for over two weeks and am very pleasantly surprised at how comfortable they are. I barely notice that I am wearing it and now I can't imagine NOT sleeping in one!  I will definitely be ordering several more of these to sleep in as well as wear casually during the day.