Review: Icebreaker SS Atlas base layer

The base layer is the first layer of clothing against your skin. A perfect base layer would help drive moisture away, maintain temperature constant and feel good. I’ve always been interested in the great properties of Merino wool used in this type of kit. On paper it seems to fit the bill like no synthetic fabric can, but how is it in real life?

The SS Atlas is a merino base layer made by Icebreaker, one of the biggest manufacturer of merino clothing for the outdoor sector.

When you buy new kit, the brand you buy it from is equally important as the product itself and here Icebreaker seem to do pretty well. They are committed to the environment, take care of their producers and show good transparency about where the wool is from. When we got in touch they were happy to send us a few tops for testing, and the SS Atlas is one of them.

The gear

You might have guessed it, but SS stands for short sleeve as the Atlas also comes in long sleeve (L/S). It’s part of the all season “active base layer” range and uses the lightest merino weight, 150g/m2 for “hot to cool” conditions. That’s good because here in Barcelona it’s pretty hot at the moment.

Testing conditions

I’ve had the SS Atlas for a month now. I’ve worn it in various conditions: day hiking in hot sunny weather on its own, evening running on its own, climbing indoors on its own and on a rainy day under a waterproof jacket (Gore-Tex membrane). This review will be updated when I get some cool/winter testing done.

First impressions

Out of the box you will first notice the great texture of the fabric. It’s made of 100% merino wool but is still stretchy, for a better slim fit. It comes with a unique code for tracing. For exemple mine is made from wool produced in 4 different location in New Zealand.

It’s also more itchy than I thought. I pulled off my cotton shirt and put it on and no, it’s not the same feeling. It’s lighter but not as comfortable. It looks also more fragile than synthetic or cotton fabrics. (Don’t run away just yet, this is the first impressions there is more to come).

The stitching is good and made in a way that leaves great freedom of movements. The neck is also a bit wider so you never feel it against your neck.

In use

I was not going to give up just on the first impressions though. There is more to merino than just the feeling on the skin. So I took it for a spin in a day walk in very hot weather ( > 30 C) at the Collserola park, just behind Barcelona. I wanted to see how it would manage sweat and heat.

The path I chose starts upward so you get right into the action. After half an hour or so I was in the right state to test the properties of the Merino. Sweat gets instantly absorbed by the wool and I didn’t have the clammy feeling of the wet shirt either, more like a neutral sensation.

I also forgot about the itchy feeling of the first impression. When a bit of air circulate it feels like a second, if slightly hairy, skin but it’s not itching. The SS Atlas combined with a ventilated backpack like my Osprey Exos made for a great walk.


All other times I had the base layer on were of the same output: get use to it for the first minutes then enjoy. It was a real pleasure to wear when bouldering at the local climbing center. It’s very light so you just forget about it.

Also, what everybody say about merino wool not stinking, well that’s actually true. Mine hasn’t been washed in three weeks (washed it on the first day before putting it on) and smells like the first day. So far nothing I did with it left any apparent damage so it might be more durable than it looks (I will update this review in a few months time if this changes).

Wrap up and final words

I still need to use the SS Atlas in the cold season but so far I am loving it. It’s a bit itchy but feels better during activities than any of the synthetic shirts I have. Merino is also a great fibre. It’s natural, almost care free, light but most importantly: biodegradable. That weights a lot in my balance.