I cannot say enough good things about these pants as a base layer! They fit comfortably under my running tights and have been able to wear just that on multiple hikes in 30 weather in the Rockies. They have been through the wash and dryer twice now and never shrank/stretched out. I am a size 12-14 and the large are just a little bit loose. I've even started wearing them to bed on cold nights, they are that comfortable.