Space underwear also doubles as sportswear for exercises aboard the station. They believed that it was made of lycra. This is a pure cotton, however. The manufacturing process of such cotton fabric has been refined over decades. Not everything is unisex Camelia A and Camelia SM are unisex.
Men wear it with no extra pieces of underwear.
For women, it's a different matter. For this reason all women will have a regular Earth-like lingerie. Women cosmonauts and astronauts on Mir are given the opportunity to select the undergarments they most prefer. The goal of this support is to make women on board feel like women, not just astronauts or cosmonauts. Shannon Lucid and Elena Kondakova liked their lingerie very much.