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Women's Janji Runterra Bio Boxy Tee



The Janji Runterra Bio Boxy Tee is a sustainable t-shirt that you can comfortably run and sweat in.

This synthetic-blend running shirt breaks down in a landfill, not your closet. The Runterra Bio Tee biodegrades like a 100% cotton tee thanks to the specifically-formulated 37.5® polyester that can break down in four years (but only in an anaerobic or oxygen-poor environment). Conventional polyester, on the other hand, takes over 400 years to break down.

Not only is this shirt environmentally friendly, but it is super soft and comfortable thanks to its premium cotton blend. The 37.5® polyester also has microscopic volcanic ash that gives you enhanced thermal, vapor and odor regulation, so you stay comfortable all run long and won’t need to wash it as often.

The shoulder seams are rolled back off the top of the shoulders for ergonomic comfort, while the slightly cropped silhouette hits above the hip for a stylish look. The top is made from 70% natural fibers, so some shrinkage may occur.

Look great, feel comfortable and help the environment with the Janji Runterra Bio Boxy Tee.


Size S M L XL
Bust (in) 34"-36" 37"-39" 39"-41" 41"-43"
Waist (in) 25"-27" 27"-29" 30"-32" 32"-34"
Hip (in) 34"-36" 37"-39" 40"-42" 43"-45"


70% Supima® cotton, 30% 37.5® tech polyester

Why do biodegradable synthetics matter?

Janji gear is designed to last and hold up to the demand of years of running, but no tee or running shorts should last forever. With this in mind, Janji is researching innovative ways to improve end-of-life cycle management of their apparel. While we look into longer-term solutions and circular methods — recycle, repurpose and reuse programs — we also know that most textiles are thrown out and end up in landfills. Conventional synthetics, used heavily in active apparel for their high-performance functionality, do not biodegrade in typical landfill conditions. This includes synthetics made from recycled materials, and is why most plastic seemingly lasts forever.

Janji is seeking solutions to fix this as a performance apparel company that relies on synthetics, including the use of non-ecotoxic biodegradability within our textiles like this new Runterra Bio. This is the first step on a better path forward.


The biggest sustainable aspect of the Runterra apparel is that the 37.5® tech polyester is biodegradable.

Runterra is also made from premium, long-staple Supima® cotton which is 50% longer and up to 45% stronger than other cottons (and softer, too). The stronger the fiber, the more durable the garment, and therefore the more it can be worn. Supima® cotton is grown by a select few family farms that utilize advanced water and soil management techniques to reduce consumption and ensure the health of the land for optimal renewability.

Runterra fabric is also OEKO-TEX® certified, meaning it is free from harmful chemicals and is fabricated in a way that meets a high environmental standard.

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