I ordered this shirt two sizes bigger than what I normally buy and it was so tight that I needed a pair of scissors to cut it off ! Albeit strong construction, it would have been very unpleasant to wear. I am 6'2" and 190 lbs. I needed a base layer to help keep my back in alignment for running.I ordered an XXL and I'm not sure that a XXXXl (max size listed) would work.