I normally wear a size large shirt and t-shirt, but to get the desired compression effect, I went one size smaller to a medium. I would recommend the same to others. Also, you are charged for shipping for each unit, so there is no benefit to purchasing more than one at a time, although they will ship multiple sales in one package. Bummer. So, purchase one, then determine what works for you before buying another.
Rating: [4 of 5 Stars!]