Little thicker than most long underware bottoms but these should not be considered cold weather baselayers. At 12% spandex these are comfortable with great freedom of movement for working out or cool/moderately cold outdoor activity. For slight compression fit size chart is right on. I'm 5ft-8in, 160lbs, 32 in waist size small was perfect fit - a little unusual compared to other under clothes garments. good value.