Testing Icebreaker's 100% Merino Wool Garments

Our equipment experts put the Icebreaker merino wool base layers to the test in order to see how they compare to synthetics.

Merino sheep, the inspiration behind the brand
By now, most outdoor athletes are familiar with the New Zealand brand Icebreaker and how it has pioneered the use of merino wool to create high-quality layers for outdoors, performance sports, and urban use. Starting in 1994, they have successfully marketed a wide range of merino wool garments, from accessories such as gloves and hats to jackets. However, where Icebreaker really excels is with its line of base layers, which it markets as high-quality, natural fibre alternatives to the synthetics that are so popular now.

The merino is one of the world’s most ancient breeds of sheep. They are different from regular sheep that roam the lowlands in that they can survive in extreme weather conditions. While the origins of the merino are disputed, they currently make their home in New Zealand's rugged Southern Alps mountain range, enduring scorching summers and freezing winters. In the summer, the merino’s thin, light, breathable coat keeps him cool in temperatures that hit 35+ °C. During the winter, they grow an extra layer of wool over their base coat as protection against temperatures that plummet to -20 °C. Nature provided the merino with this adaptable wool, which Icebreaker then turned into a lightweight system of all-season garments that are ideal for outdoor athletes.


Fibre Structure

Merino wool is built from a natural protein named Keratin that protects cells from damage and is the key structural material that makes up the outer layer of skin. Icebreaker merino fibres are typically between 17-19 microns (half that of standard wool) and not made of plastic like in synthetics. This means that merino fibres are much finer and smaller, allowing them to flex when in contact with the skin, leading to increased comfort for the user.

Comparison of diameter: polyester fibres, merino wool and conventional wool
Moisture Management

Merino wool combines its natural breathability and capacity to absorb moisture to keep you dry. Although it is not as breathable or quick drying as a synthetic wool, it is still relatively fast drying for a natural fibre (much more so than cotton, for example). And unlike synthetic fibres, it can absorb up to 30% of its own weight in moisture before you start to notice any dampness, meaning you won't be suffering from the clamminess that occurs with synthetics when their drying capacity has been exceeded.

Temperature Regulation

Merino wool is thermostatic, which means it will keep you comfortable in a wide range of temperatures. In cold weather, merino wool acts as a great insulator from the cold. Its fibres contain millions of air pockets that lock in body heat to help keep you warm. At the same time, in hot temperatures or during intense aerobic activity, you won't overheat or get clammy skin as with traditional wool or synthetics. As a breathable fibre, merino wool wicks away sweat and allows it to evaporate, keeping you cool.

Odour Resistance

If you have ever worn technical synthetic base layers made of polyester or Lycra, you will already know that after a few hours of activity, they will not smell like roses. Being an outdoor enthusiast, you could potentially find yourself in situations where you might need to wear the same clothing for an extended period of time, which can become an embarrassing position to be in among your party.

Luckily, as a natural animal fibre, Icebreaker merino has anti-microbial properties that inhibit the growth of bacteria. They resist odour naturally, and can be worn for days – even weeks – without washing, which cannot be said of synthetic fibres. This is noticeable in the long term as well, since bacteria eventually build up on synthetics no matter how many times you wash them. However, this is not the case with merino wool garments. They are more resistant to bacteria and last longer before you have to throw them out.

Now that we have a better understanding of merino wool's composition and how it works, let's find out how it performs in the real world. Our gear expert Timothée from the Peignée Verticale blog tested the Oasis Icebreaker Men's Long Sleeve Half Zip and The Icebreaker Oasis Leggings 200 base layers in a variety of different activities (ski touring, mountain biking, skiing and trail running).


When Timothée tested the Oasis Icebreaker Men's Long Sleeve Half Zip shirt, he noticed several benefits. Right from the start, he appreciated its versatility. While it is ideally used as a breathable base layer for highly aerobic outdoor activities such as mountain biking, trail running, hiking, and snow sports, it can also be worn as a fashionable stand-alone piece, weather permitting. It is soft, comfortable and warm. It is breathable and the semi-zip is useful to aid in temperature control. Additionally, it has an adjustable fit so that it adapts specifically to your body type.

After wearing and testing it out for a few hours, the anti-bacterial properties of the merino wool were really noticeable. Unlike a Lycra shirt, the Icebreaker shirt had no distinguishable odour. It is also machine washable, which is convenient.

The Oasis Icebreaker Men's Long Sleeve Half Zip – Available for Purchase HERE


The other base layer that Timothée tried out was the Icebreaker Oasis 200 Leggings for men. Just like with the long sleeve half zip, their versatility was immediately evident. Not only can the leggings be worn during outdoor sports, they are great for down times in the hut as well. He used them as a stand-alone piece after a long day of ski touring in order to stay dry and warm, and even slept in them. He noticed that during the night, in addition to keeping him warm, they were also comfortable and surprisingly didn't itch like traditional wool.

The Icebreaker Oasis Leggings 200: Available for Purchase HERE

After rigorous testing in several different sports and activities, Timothée concluded that the Icebreaker merino wool garments are his favourite technical base layers to use. While they are a little more expensive than other brands and types of fibres, they are worth it due to their performance, even in extreme weather conditions. This makes them perfect for intense aerobic activities such as ski touring, climbing, mountaineering and trail running. Icebreaker has worked hard over the years to improve the quality of their products and now these base layers itch less, and control temperature and moisture better than before. Furthermore, the naturally anti-bacterial fibres make them odour resistant and long lasting, which makes up for the higher price tag.

See our Full Range of Icebreaker Products Online – Shop Icebreaker

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