Run in it, sweat in it, live in it — then biodegrade it! The first synthetic-blend running shirt that biodegrades like a 100% cotton tee, our Runterra Bio offers the enhanced moisture and odor control of specially-formulated 37.5® polyester with the comfort and versatility of cotton. This new, innovative fabric breaks down into organic compounds in under four years. Conventional polyester takes four hundred. Don’t sweat it — this tee will only start to biodegrade in anaerobic (oxygen-poor) environments. It breaks down in the landfill, not in your closet. Biodegradable Runterra Bio is powered by a specially formulated 37.5® polyester with enhanced biodegradation to break down into bio-based compounds in under 4 years in an oxygen-poor environment like a landfill Premium cotton Made from long staple, US-grown Supima® cotton for superior softness, strength + durability Active comfort Blended with 37.5® polyester, a special technology utilizing the natural benefits of microscopic volcanic ash to provide enhanced thermal, vapor + odor regulation to maintain body comfort during activity Wear more, wash less The natural odor resistance of cotton is boosted by the volcanic particles which "trap" odors so you can put this top through repeated wear Ergonomic comfort Shoulder seams are rolled back off the top of the shoulders for ergonomic comfort Shrinkage is natural This top is made from 70% natural fibers and is not pre-shrunk so some shrinkage may occur, up to half a size