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Runterra Bio Long Sleeve

Runterra Bio Long Sleeve

W's Runterra Bio Long Sleeve

Heads up, this gear will ship in 3-5 weeks. Learn more about pre-orders.


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run everywhere guarantee
free shipping over $50
free 60 day exchanges
Gabby wears size S and is 5'08" Regular fit, Size Chart

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.
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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
37.5® polyester with embedded volcanic ash provides enhanced heat + moisture regulation as well as odor-resistance

New sport raglan
Signature raglan sleeve design keeps seams off the top of the shoulders for comfort

Hang it up
An elastic locker loop is integrated into the back neck tape

materials + specs

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

Garment made in Vietnam

Fabric Callout


Lightweight, resilient, and versatile, Runterra wears like your softest cotton tee with the added benefits of active odor-resistance and thermoregulation — thanks to volcanic particles embedded within the fabric.


care instructions

Wash cold with like colors

Machine dry low or hang dry for best results and lifespan of the garment

Heads up — Runterra is not pre-shrunk

We have relaxed the body and slightly lengthened the sleeves of this top to accommodate for some shrinkage which may occur in the wash cycle since Runterra is made from a majority natural fiber.

Avoid washing and drying with high heat.


Why do biodegradable synthetics matter? 

While we design Janji gear to last and hold up to the demand of years of running, no tee or running shorts should last forever. With this in mind, we are researching innovative ways to improve end-of-life cycle management of our 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.

We are 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.

Runterra is 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.

Learn more about our sustainable initiatives here.


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Customer Reviews

Based on 24 reviews
Kristi Rose
Wear it for: Running
Product Fit: Spot-on
Height: 5'10" to 6'0"
Usual Size: M
Size Purchased: M

Doesn't stink after running....which is so great compared to so many other synthetic material shirts. I'm really happy I made this purchase, will likely be getting more.

Wear it for: Running, Hiking, Camping, Climbing, Cycling, Mountain Biking
Product Fit: Spot-on
Height: 5'7" to 5'9"
Usual Size: S
Size Purchased: M
The only outdoor long sleeve you need!

The thickness of this shirt is perfect- not to heavy but certainly holds some warmth, and dries quickly when getting your sweat on. I love the neckline and fun pattern too :)

Wear it for: Running
Product Fit: Spot-on
Height: 5'1" to 5'3"
Usual Size: S
Size Purchased: S
Soft running shirt!

I like this shirt for running and for casual wear! So soft. Does shrink a little when washed. I ordered the obsidian color and it is really pretty!

J. Su
Comfortable shirt

Got this shirt for running but it’s so soft and nice I have been wearing it daily, good quality doesn’t get itchy on the seam which is great!

Comfy cute workout shirt

Super soft and fits great - loose enough to feel not all bound up - but fitted enough to be attractive- more stock in other colors please!

Danielle Castaldi
Great technical base layer

Love this shirt for hiking and camping on chilly days/nights. Want to buy it in every color! Love this shirt so much the antiodor and quick dry is amazing!

Technical & fun running shirt

I don't think I've run in another long sleeve running shirt that I love more than this. It dries easily & is warm but lightweight. I need more colors because I love wearing this shirt casually as well!

Susan Tamasi
Win-Win long sleeve running shirt👍

Comfortable & very cool print design & color. I love all Janji & thank my friend & owner Charlotte Walsh-Charles River Running in Norwood MA for introducing me to this top notch running apparel!

ann snowden johnson
Happy Runner indeed!

Another win from Janji! Great top -- easily layered and fantastic on its own!

Anna P
Comfy, yet technical!

Love this shirt for many reasons. 1. It looks cool and the art is rad. 2. It’s comfy to wear around the house/run errands 3. Technical enough for a run and layering piece. I want all of them!