Brynje Wool Thermo Light T-Shirt review – middle of the road base layer

Mesh but not too mesh, and wool but not too wool – is Brynje’s Wool Thermo Light the best of both worlds or the best of neither?

Mesh cycling base layer
(Image: © Sean Fishpool)

Bike Perfect Verdict

It has slightly less performance than Brynje’s excellent Super Thermo, but the Wool Thermo Light is comfier, looks a bit more normal, and stays fresher.


  • +

    Great temperature regulation

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    Warm and comfortable

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  • +

    Surprisingly dry, for 80% wool

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  • -

    Doesn’t wick as well as the pure synthetic version

  • -

    Need washing a bit more carefully than synthetics

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Norwegian brand Brynje makes pretty much the definitive performance base layer in its 100 per cent polypropylene string mesh Super Thermo. The polypro can be a bit rough but its wicking and dryness is genuinely amazing, and the string mesh traps warm air when you want it, and then dumps it as soon as you open the zip on your top layer. 

If the wide string mesh presents you with an aesthetic challenge, or you’d prefer something gentler or less inclined to hang on to sweaty smells over multi-day trips than polypro, you’re in luck: Brynje makes a number of variants. The synthetic summerweight finer mesh Super Micro T-shirt is one, and the Wool Thermo Light is another, using the finer mesh and an 80 per cent merino wool, 20 per cent polyamide mix. Read on and you’ll see why the Wool Thermo Light easily wins best base for temperature control in our guide to the best winter base layers.

Mesh cycling base layer

Definitely not outerwear (Image credit: Sean Fishpool)

Design and specifications

There’s nothing particularly complicated about the Wool Thermo Light. It’s relatively square cut, with non-chafing flatlock seams and hems, raglan sleeves to help arm mobility, and a long body to keep things tucked in. The fabric is very much a mesh, designed as underwear, but it’s not nearly as open as the regular Brynje meshes. 

Merino wool is well known for softness, and for feeling warm even when damp, and the 20 per cent polyamide in the fabric helps both to add durability, and to wick moisture away.

Brynje pitches the wool Thermo light as ideal for low to medium level activities – so more for exploring than racing – and for spring to fall, though bear in mind in Norway this gives a generous span of -10C to 20C.

Brynje has a long-standing commitment to the environment, also aiming to make their clothes last and encouraging people to hang on to them. They’re Bluesign and Eco-lighthouse certified, and their merino wool is produced without harm to the sheep.

Mesh cycling base layer

The mesh traps warm air when you need it, breathes when you don’t (Image credit: Sean Fishpool)


As a longtime Super Thermo user, and a rider who’s less than convinced about merino base layers, I was expecting to dismiss the Wool Thermo Light after a few rides, and probably not even include it in our guide to the best winter base layers. But I’ve been pleasantly surprised, and the Wool Thermo Light has turned out to be a base I’ve worn because I want to rather than just because I’m reviewing it.

The way that a mesh base traps warmth when you want it, and releases it when you unzip your midlayer is perfection to me. It saves gradually boiling in the bag on climbs, or yo-yoing between putting layers on and taking them off.  Often combined with arm warmers, which are easy on, easy off, this flexibility sees me through much of winter and the shoulder seasons. 

And like the summer Super Micro T-shirt, the Wool Thermo Light gives a lot of that flexibility, without the full-string looks. With the mesh design, and the 20 per cent polyamide, it’s way drier and better at temperature regulating than a pure merino flat-woven tee (though obviously without the versatility of being able to wear it as a regular tee by itself if you want). I thought that the Wool Thermo Light would only be fine for the gentlest of rides with very breathable layers on top, but even for a steady hilly ride with a rain jacket on top, it was surprisingly dry, and under where I’d been wearing a backpack it was only moderately damp rather than wringing wet. 

I think it has a smidge more stretch than its fully synthetic cousins in the Brynje range, which made for a less baggy fit around the shoulders and underarms. And like the others, it has a generous length and a nice high crew neck.

Mesh cycling base layer

Plenty of length for tucking in (Image credit: Sean Fishpool)


Even though I liked the Wool Thermo Light, I’m not 100 percent sure I’d buy one with my own money. The merino is nice but it still leans more towards functional than snuggly. If I want pure performance I’ll probably stick with the Super Thermo, and if I want snuggly, I’ll go with a brushed synthetic base like the Giro Chrono Base or the max-warmth Spatzwear Race Layer.  It’s a treat for occasional use and a nice option for multi-day bivvy trips, and if you do want merino, you’ll find it a lot more functional than the flat-weave alternatives.

Tech Specs: Brynje Wool Thermo Light 

  • Price:  $80 /£65 / €71
  • Color: Black
  • Weight: 110g
  • Sizes: S-XXL, unisex
  • Materials: 80% merino wool, 20% polyamide
Sean Fishpool
Freelance writer

Sean has old school cycle touring in his blood, with a coast to coast USA ride and a number of month-long European tours in his very relaxed palmares. Also an enthusiastic midpack club cyclocross and XC racer, he loves his role as a junior cycle coach on the Kent/Sussex borders, and likes to squeeze in a one-day unsupported 100-miler on the South Downs Way at least once a year. Triathlon and adventure racing fit into his meandering cycling past, as does clattering around the Peak District on a rigid Stumpjumper back in the day.

Height: 173cm

Weight: 65kg

Rides: Specialized Chisel Comp; Canyon Inflite CF SLX; Canyon Aeroad; Roberts custom road bike