Fit a little big for xs, but I likely need and xxs as I am extremely petite. I was looking for very thin long johns for everyday office worlk wear that I could use under leggings without being bulky. They are a little bulky because they are too big for me, but for a regular sized person, this should not be a problem. The fabric was quite thin, which is what I was looking for. I hope they will be durable. If you want warmer and thicker, I highly recommend merino wool instead. I would say that dueSee full review