Unlike 100% cotton garments, our performance t-shirts are designed to keep wearers cool and dry. Cotton absorbs liquids, including sweat, very efficiently. This can result in wet cotton clinging to the body and causing discomfort. Performance garments made with polyester content or 100% polyester have moisture-wicking properties that can help keep wearers dry. Polyester does not retain moisture well and the layers of fibers in these shirts will help move sweat to the outside of the garment where it can evaporate without clinging to the body.