Looking for a warm weather alternative to cotton? Flax is the oldest known fabric, and it’s comparable to cotton in all ways – some even better. Flax is eco-friendly and great for high moisture and humidity areas. Flax, otherwise known as linen, is less likely to mildew, keeps the body cool, and can cost less than cotton. Another bonus – flax is less likely to fade in the sun. Wondering why some shirts say flax while others say linen? Flax sounds more eco friendly than linen – but have no fear, they are the same great fabric.