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men'S tops

Runterra Bio Long Sleeve

Regular price $64
Unit price  per 

Runterra Bio Long Sleeve

M's Runterra Bio Long Sleeve

Heads up, this gear will ship in 6-10 weeks. Learn more about pre-orders.


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run everywhere guarantee
free shipping over $50
free 60 day exchanges
Aron wears size M and is 5'11" Athletic 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 significantly faster than conventional polyester which takes over four hundred years.

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 significantly faster than conventional synthetics 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

147g / 5.2oz (M's Medium)

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 20 reviews
conor may
Wear it for: Running, Hiking, Camping, Climbing
Product Fit: Spot-on
Height: 6'3" or taller
Usual Size: XL
Size Purchased: XL

M's Runterra Bio Long Sleeve

william m mullings

great shirt--i like the fit and color options. the sleeves are way, way too long, however.

Kiernon Murray
È un camicia formidabile!


Tony Ramirez
Super soft shirt

Love the shirt for everyday casual wear. Super soft and comfortable. I received my first Runterra LS as a gift. Sleeves ran a bit long, but I liked the material so I bought a second one (a size down) for myself and the fit is great! I’m looking a Runterra SS now that the weather is warming up.

love this longsleeve

I ordered this in size medium and was stoked with the fitting. I've taken it out for long runs on the road and on the trail with without a layer underneath and it fit well untucked. I mention untucked because I found that when it was tucked in, the large graphics on the back sticked more to my skin when sweating or in the rain. I wonder if it has to do with the amount of ink or the ways the graphics were screened on the shirt that it creates this feeling. If worn normally, I found that this occurred less so when not tucked in. Other than that little detail, the shirt feels great!

Miguel Millan
Amazing fit and feel

This is my first Janji piece. Totally loved it. The feel of natural fibers is unbeatable.

Dhara Balaji

M's Runterra LS Tee in Sage

Great fit long sleeve

Lightweight long sleeve t-shirt great for the cooler NC morning in the winter.

James Nee
New LS Convert

I've never liked running in LS before. In the past, I would just rather take a light jacket. But this fabric makes me think differently. Very breathable and soft. Yes the sleeves are very long, but I just tuck my hands in them when I'm cold and scrunch them up when I'm too hot. Perfect piece for those transition weathers, and a great layer to add to your colder runs.

First spin

Hey all, just got off my spin bike and what can I say?!? This new Runterra is fantastic. Fit was great, felt comfortable even when sprinting. Can’t wait to take it out on the road for my next run! Well worth it, and awesome color a d design!