The most common materials for the men's briefs in this category are cotton and polyester. Cotton also has a breathable function which makes them very comfortable to wear. Polyester, another widely used material in men's underwear, is slightly less breathable than cotton and therefore feels less warm. Cotton briefs may shrink slightly after the first wash . So keep this in mind! However, to enjoy your briefs as long as possible, we recommend that you wash the underwear by hand .