Ultimate Direction Jason Schlarb Merino Tee review: an ultra-running top that stays the distance

The Ultimate Direction Jason Schlarb Merino Tee has been designed by a top ultra runner for ultra runners

Ultimate Direction Jason Schlarb Merino Tee review main image size
(Image: © Pat Kinsella)

Advnture Verdict

Sublimely comfortable to wear, designed to promote freedom of movement, and constructed from a fabric mix that means it can be worn for many hours – several days even – out on the trails without smelling awful, the Ultimate Direction Jason Schlarb Merino Tee is ideal for ultra and long-distance running in all kinds of conditions. So long as you like the color onyx, and can stomach the price.


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    Great next-to-skin comfort

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    Wicks moisture

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    Natural odor-busting properties

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    Underarm gussets for free-feeling arm movement

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    Made with responsibly sourced and cruelty-free wool, and a partially plant-based fabric called Sorona


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    Heavy when wet, and not as quick to dry as synthetic tops

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    One color only (and it holds the heat)

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Ultimate Direction Jason Schlarb Merino Tee: first impressions

The Ultimate Direction Jason Schlarb Merino Tee is one of Advnture's best running tops, and part of a collaboration between Boulder-based running gear and apparel brand Ultimate Direction and Jason Schlarb, an endurance athlete and coach who has many ultra running achievements and accolades to his name (including a Hardrock 100 win, alongside Kilian Jornet, plus three Run Rabbit Run 100 victories and a top-five UTMB result, when he was the first American over the finish line). 


• List price: $79.95 (US)
• Sizes available: Small / Medium / Large / Extra Large
• Center Back Length: 72.39cm / 28.5in
• Weight (medium): 118g / 4.16oz
• Materials: Merino (50%) and polyester (50%)
• Colors: Onyx

The perfect accompanying top half to Jason Schlarb running shorts, this premium-priced running tee has been designed for long outings in all sorts of conditions and across varying terrain. To achieve that, it’s made with merino and Sorona mesh, body-mapped into high sweat zones for optimal breathability. 

Or, at least that’s the claim. I’ve been putting it to the test to see whether it’s worth its price tag and to assess its potential.

Ultimate Direction Jason Schlarb Merino Tee: on the trails

Ultimate Direction Jason Schlarb Merino Tee on grass

For big runs in tough conditions, the Ultimate Direction Jason Schlarb Merino Tee (Image credit: Pat Kinsella)

I’ve been wearing the Ultimate Direction Jason Schlarb Merino Tee on running adventures of varying lengths, across all sorts of terrain and in a wide range of temperatures and conditions. It accompanied me on several winter and spring trail escapades – both fastpacking forays and running ventures – where it performed well, supplying warmth when required, while proving extremely breathable. I also wore it for gorge runs amid an early summer heatwave, where it has been soaking up lots of my hard-spilt sweat.

So, what makes this tee good for big runs in tough conditions? Mostly the fact that it’s made half from merino wool and half from synthetic Sorona fabric. A magic material, the merino element wicks moisture, breathes well, provides warmth when required and keeps you cool when conditions are hot, and doesn’t stink up easily because of its natural antibacterial properties. Plus it feels absolutely lovely next to your skin.

Ultimate Direction Jason Schlarb Merino Tee closeup

A shirt with merino comfort, but with added longevity (Image credit: Past Kinsella)

Merino’s many qualities do not, however, extend to longevity, so this is where the Sorona fabric comes in, helping the tee last longer and keep its shape, so you can wear it for multiple marathon-plus escapades, or just for lots of training runs.

The flatlock seams, combined with the soft merino fabric, do make this a super comfortable tee for running in over extended amounts of time, even several days on the trot. The anti-bacterial properties mean it doesn’t get too stinky (I’ve worn it for three hot days in row before now, and while salt from my sweat visibly accumulated around my neck and underarms, the tee still didn’t pong). The underarm gussets help with free arm movement, too, and I haven’t experienced any rubbing or chafing issues.

But, there’s no denying that this is a very pricey t-shirt, and we would like to see it offered in some different, lighter colors (the onyx is very dark and attracts and holds heat in the sun). It also gets pretty heavy once it’s wet – either from sweat or rain – and takes a while to dry.

Pat Kinsella

Author of Caving, Canyoning, Coasteering…, a recently released book about all kinds of outdoor adventures around Britain, Pat has spent 20 years pursuing stories involving boots, bikes, boats, beers and bruises. En route he’s canoed Canada’s Yukon River, climbed Mont Blanc and Kilimanjaro, skied and mountain biked through the Norwegian Alps, run an ultra across the roof of Mauritius, and set short-lived records for trail-running Australia’s highest peaks and New Zealand’s Great Walks. He’s authored walking guides to Devon and Dorset, and once wrote a whole book about Toilets for Lonely Planet. Follow Pat’s escapades on Strava here and Instagram here.