In the composition, not only the names of the fibers matter, but also the proportions: they are what determine how a garment behaves in wear.
Cotton
Breathable and pleasant to the skin, but wrinkles and stretches at points of flex. Pure cotton works well for T-shirts and loose-fit shirts.
Elastane at 3–5%
Gives the item the ability to recover its shape. That's why jeans with a small percentage of elastane don't stretch out at the knees.
Polyester
Holds its shape and dries quickly, but breathes less well. In a blend with cotton, it's a smart compromise for outerwear.
