These briefs are made of 95% Modal ( a type of rayon) and 5% Spandex. Even though modal is semi-synthetic, it is breathable and does not retain humidity. They are not cotton, but feel very soft and comfortable. I ordered them XL even though I am MED because Asian sizes run smaller. They fit perfectly. The seams are unnoticeable to the skin. They may be a little overpriced, but hopefully this higher price translates into more durability. Time will tell if they are worth it. So far I like them.