Guaranteed Delivery by 12/24

Free shipping on all orders $50+

Free Exchanges + No-fuss Returns

Explore our Staff Picks

run everywhere
free shipping on
orders over $50
free 60 day exchanges
+ no-fuss returns
men'S tops

Runterra Bio Long Sleeve

Runterra Bio Long Sleeve

M's Runterra Bio Long Sleeve

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


Join now to unlock access


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.
Read more

Explore more


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.


Already a Janji Collective member? Log in to unlock access now.

Customer Reviews

Based on 30 reviews
Bobby Bretz
Wear it for: Running, Hiking, Camping
Product Fit: Spot-on
Height: 5'10" to 6'0"
Usual Size: M
Size Purchased: M
So good I ordered another

The material is very comfortable and perfect for both lounging around and running. I was surprised to find that the odor resistance is as good if not better than a lot of the wool-blend running shirts and base layers I own. The fit is spot on, not too tight nor too loose. I like to wear it all day and then keep it on for my next run so I get to use it both as a daily and a running shirt on a single wash. It could even be worn on multiple runs with just a rinse in between, and not stink up your house. After a couple of weeks of owning it, I bought another one even though I don’t need more shirts. I bought a lot of long sleeve fitness shirts this season and wish I could go back and replace them all with more of these.

Raimond Galicia
Wear it for: Running, Hiking, Cycling, Mountain Biking
Product Fit: Runs large
Height: 5'4" to 5'6"
Usual Size: M
Size Purchased: M

M's Runterra Bio Long Sleeve

Jordan J
Wear it for: Running
Product Fit: Spot-on
Height: 5'10" to 6'0"
Usual Size: S
Size Purchased: S
anti-odor, great for runs

perfect fit for me here. absolutely obsessed with this shirt, from the run to the bars. nice work Janji... I get lots of compliments.

Gray Adkins
Wear it for: Running, Hiking
Product Fit: Runs large
Height: 5'7" to 5'9"
Usual Size: S
Size Purchased: S
So soft.

Love this tee. Super, super soft and feels much drier than my other cotton blend performance tees. Absolutely perfect for fall runs. Only wish it came in an xs as it fits looser in the small than I normally wear my tees.

Shawn Ingram
Wear it for: Running
Product Fit: Runs large
Height: 6'0" to 6'2"
Size Purchased: L

M's Runterra Bio Long Sleeve

Jacob Neumann
Wear it for: Running, Hiking, Camping, Climbing
Product Fit: Spot-on
Height: 5'10" to 6'0"
Usual Size: M
Size Purchased: M
This is a new staple for me.

This shirt is becoming a staple in my everyday life as well as running. From waking up early and tossing it on to make my coffee, or running on a chilly day. This shirt can do it all. It is a relaxed fit that keeps you warm but truly keeps it fresh to wear all day. The odor resistance is REAL. I can smell after my runs... I wash it, air it out, and you can't tell I ran a long run in it (oh yeah, its comfortable enough for a long run too.) you should buy this shirt.

Juan J. Arrieta
Wear it for: Running
Product Fit: Spot-on
Height: 5'7" to 5'9"
Usual Size: M
Size Purchased: M
Extremely comfortable

Love this long sleeve. Have used it a couple of times already and it is ultra comfortable whether to run or just hang out. Will be quite useful with cooler fall temps and in winter as well. Will likely order another one on a different color soon.

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!