Good question. Cotton is a natural fibre, with natural features such as moisture management and softness. (Isn't it wonderful what the world produces all by itself?) Polyamide is a synthetic fibre that is already used in clothing that we are familiar with, including sportswear and swimwear.
Polyamide is what makes our period pants so durable, fast-drying and contributes to the lack of odour when used. If natural is what you prefer, the body fabric in our Essentials range is made from 100% sustainably sourced organic cotton.