Icebreaker Oasis
A base layer is one of the most vital pieces of hiking clothing because it is in direct contact with your skin and thus has a big impact on your comfort level and performance. Base layer clothing is responsible for managing perspiration, protecting the skin (UV rays, chafing etc.) and maintaining your body’s natural temperature. Therefore, a base layer should be moisture-wicking, quick-drying, durable and breathable. Hiking base layers are made of polyester, Merino wool or nylon. Sometimes blends of these materials are used to mitigate the respective shortcomings of each material.
However, Merino wool is becoming the material of choice when it comes to base layers – exactly because it offers superb breathability and moisture wicking performance in comparison to competitive materials such as polyester and nylon. Furthermore, Merino wool is also naturally antimicrobial, super soft to the touch and provides goos UV protection (read more about sun-protective clothing in this article). The natural material, however, also has downsides – it is relatively expensive, dries slightly slower than synthetic materials (see our experiment) and is often also less durable than synthetic materials. If you want to learn more about different base layer materials and their respective pros/cons, check out our Comparison of Base Layer Materials.
Here we selected and reviewed the best Merino wool base layers for hiking, mountaineering, trekking and other outdoor activities.
We deliberately listed only long-sleeved base layers as they offer great performance most of the year – on the warmest summer days you will probably want a lighter short-sleeved base layer.
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Gender
This selection includes primarily men's products. For women's products check out the Best Merino Base Layers for Women
1. Our Merino Wool Base Layers Picks
Best Merino Base Layers for Hiking
- Icebreaker Oasis Long Sleeve Crewe
- Smartwool Classic Thermal Crewe
- Woolly Everyday Henley
- Ortovox 185 Rock’N’Wool
- Minus 33 Chocorua
2. Comparison of Merino Base Layers for Hiking
| Feature/Product | Icebreaker Oasis Long Sleeve Crewe | Smartwool NTS Mid 250 Crew | Woolly Everyday | Ortovox 185 Rock'N'Wool | Minus 33 Chocorua |
|---|---|---|---|---|---|
| Material | 100% Merino wool | 100% Merino wool | 100% Merino wool | 100% Merino Wool | 100% Merino wool |
| Fabric Density | 200 g/m2 | 250 g/m2 | 190 g/m2 | 185 g/m2 | 230 g/m2 |
| Fit | Slim | Form | Regular | Athletic fit | Regular |
| Washing | Machine Wash | Machine Wash | Machine Wash | Machine Wash | Machine Wash |
| Odor-resistant | Yes (natural resistance) | Yes (natural resistance) | Yes (natural resistance) | Yes (natural resistance) | Yes (natural resistance) |
| UV Protection | Yes | Yes | Yes | Yes | Yes |
3. The Selection
Icebreaker Oasis
1. Icebreaker Oasis Long Sleeve Crewe
Suitable for:
- Hiking
- Mountaineering
- Trekking
- Backpacking
- Climbing
- Running
- Everyday use
The Icebreaker Oasis Long Sleeve Crewe base layer is perfect for various outdoor activities. The base layer is made of 100% Merino wool fabric which has density of 200 g/m2. Therefore, this base layer can be worn year-round, except for the very warm summer days. Because it is made of high-quality pure (non-blended) Merino wool, it is very comfortable and provides great breathability, odor-resistance and moisture-wicking properties. The base layer features slim fit for low-bulk layering. However, even though the fit is slim, it offers great freedom of movement due to the stretchy material. The base layer also features offset shoulder seams and a dropped tail hem. The offset shoulder seams reduce chafing and rubbing when you are carrying a backpack while the drop tail hem prevents the fabric from riding up and exposing your back. The Icebreaker Oasis Long Sleeve Crewe is best for those who want a versatile base layer for different outdoor adventures.
Women's Version: Available - Icebreaker Women's Oasis Long Sleeve Crewe
Note: Women's version might slightly differ from the men's version.
Pros:
- Comfortable
- Fit
- Moisture-wicking
- Breathable
- Odor-resistant
Cons:
- /
Where to buy?
Also available at:
Video
Smartwool Classic Thermal Base Layer
2. Smartwool Classic Thermal
Suitable for:
- Hiking
- Mountaineering
- Trekking
- Backpacking
- Climbing
- Running
- Everyday use
The Smartwool Classic Thermal base layer differs from the Icebreaker Oasis Long Sleeve Crewe in density of the fabric – it is made of a thicker fabric. Therefore, it is perfect for winter hiking and other activities in cold weather. The Smartwool base layer is made of 100% Merino wool fabric with a density of 250 g/m2 and thus provides good insulation. However, as the fabric is quite thick, it also takes longer to dry (it absorbs more moisture) than thinner base layers. The insulation is additionally increased with the tight fit which prevents the body-warmed air from escaping to the outside. The Smartwool base layer is very comfortable because it has flatlock seams and shoulder panels (no seams in the area where the backpack’s shoulder straps come). Due to the tight fit and heavier density, the Smartwool Classic Thermal base layer is best for those who need a base layer for hiking in very cold conditions.
Women's Version: Available - Smartwool Women's Classic Thermal
Note: Women's version might slightly differ from the men's version.
Pros:
- Comfortable
- Fit
- Warmth
- Breathable
- Odor-resistant
Cons:
- /
Where to buy?
Also available at:
Woolly Everyday Henley
3. Woolly Everyday Henley
Suitable for:
- Hiking
- Mountaineering
- Trekking
- Backpacking
- Climbing
- Running
- Everyday use
Seattle-based Woolly Clothing Co. makes 100% Merino base layers in three different densities of wool – 150 g/m2 (Ultralight), 190 g/m2 (Everyday weight) and 250 g/m2 (Mid-weight). Within each category you can find different styles – for example crew neck, v-neck, Henley shirts etc. The Everyday Weight category offers the widest selection of cuts. For this list, we had to go with the Woolly Everyday Henley shirt which is designed to fit into any multi-layer scheme you might use on a hiking trip, while being stylish enough to fit into most everyday situations as well. The fabric density makes it very versatile as it can be used in all but the warmest weather. The Woolly Everyday Henley base layer is available in four muted colors.
Women's Version: Available - Woolly Women's Everyday Henley 3/4 Sleeve
Note: Women's version might slightly differ from the men's version.
Pros:
- Breathable
- Moisture-wicking
- Odor-resistant
- Quality
- Versatile fabric density
Cons:
- /
Ortovox 185 Rock’n’Wool Merino base layer
4. Ortovox 185 Rock’N’Wool
Suitable for:
- Hiking
- Mountaineering
- Trekking
- Backpacking
- Climbing
- Running
- Everyday use
For this list of the best Merino base layers, we also had to include the long-sleeved Ortovox 185 Rock’n’Wool shirt. Ortovox is a German outdoor brand with a strong focus on sustainability. This is also the case for their Merino apparel, where the wool is sourced from selected Tasmanian farms, which comply with the Ortovox Wool Promise, which is even stricter with regards to animal welfare than the Responsible Wool Standard. The brand’s 100 % Merino wool line is called the 185 Rock’n’Wool, which as the name implies, has a fabric density of 185 g/m2. The unique color blocking effects on the sleeves of the base layer are bound to make you stand out in the crowd. The Ortovox 185 Rock’n’Wool base layer is thus best for those who are not afraid to make a statement, both in terms of sustainability and style.
Women's Version: Available - Ortovox Women's 185 Rock'N'Wool Base Layer
Note: Women's version might slightly differ from the men's version.
Pros:
- Made with sustainably sourced wool
- Quality
- Athletic fit
- Fabric density (185 g/m2) is very versatile
- All the benefits of Merino wool
Cons:
- /
Minus33 Chocorua
5. Minus 33 Chocorua
Suitable for:
- Hiking
- Mountaineering
- Trekking
- Backpacking
- Climbing
- Running
- Everyday use
The Minus 33 Chocorua base layer is made of superfine Merino wool that has a fiber diameter of 18.5 microns. Therefore, the fabric is super soft and pleasant to the touch. The density of the fabric is 230 g/m2 and thus this base layer is perfect for winter, fall and spring. The Minus 33 Chocorua base layer has a regular fit for great freedom of movement. It also features tagless construction and flatlock seams for ultimate comfort (no itching or chafing). The drop tail hem prevents the fabric from riding up and exposing your back. The Minus 33 Chocorua is a great versatile base layer which keeps you comfortable in various conditions.
Women's Version: Available - Minus33 Women's Ossipee Base Layer
Note: Women's version might slightly differ from the men's version.
Pros:
- Fit
- Quality
- Comfortable
- Odor-control
Cons:
- /
4. Buying a Merino Wool Base Layer – What is important?
Material:
Merino wool fabrics differ in density, porosity and diameter of fibers. The fiber’s diameter dictates the softness of the fabric; the smaller the diameter, the softer is the fabric. Merino wool fibers have a diameter between 17 microns (Ultrafine Merino Wool) and 24 microns (Strong Merino Wool). Base layers are usually made of fabrics with densities between 130g/m2 and 250 g/m2. Fabric densities under 160 g/m2 are perfect for warm conditions while thicker base layers are best for hiking in autumn, winter and spring.
Merino wool can also be blended with other fibers such as nylon, polyester and polyamide to increase the lifespan (durability) of garments. However, such blends also have their shortcomings; the fabric becomes less soft to the touch and if the content of synthetic fibers is very high, the fabric also starts losing its breathability and odor resistance. For more information about Merino wool, read our article Why you should wear Merino wool clothing and this article from Smartwool.
Seams:
The seams of your base layer should not cause rubbing or chafing. To reduce any possible discomfort caused by the seams, manufacturers often use flatlock seams. Flatlock seams are particularly important when it comes to tight-fitting base layers. Read more about flatlock seams in our article What are flatlock seams.
Odor-resistance:
Merino wool is superior to any other material when it comes to odor-resistance because it contains lanolin (wool wax) which efficiently reduces odor-causing bacteria. Synthetic fabrics can be treated with antimicrobial agents to mimic this quality, but these treatments tend to get washed out fast.
Durability:
Pure Merino wool is not as durable as synthetic materials – nylon, polyester etc. However, some manufacturers blend Merino wool with nylon to increase its durability. This also allows them to make very thin and porous garments without jeopardizing their durability. Read more about the durability of Merino wool in our article How durable are Merino garments.
Fit:
The fit of a base layer has an impact on its performance; tight-fitting base layers are best for cold conditions while base layers with a regular or loose fit are best for warm conditions as they provide better ventilation.
5. Questions and Answers
What is special about Merino wool?
Merino wool is naturally antimicrobial which means that it does not get smelly even if you sweat extensively. It is also very breathable, moisture-wicking and soft to the touch. Therefore, it is a great material for next-to-skin clothes.
Is Merino wool better than regular wool?
As a baselayer – definitely! Merino wool fibers have a smaller diameter than regular wool fibers and therefore Merino wool is not itchy or uncomfortable to wear directly on your skin.
How to wash Merino wool clothes?
Merino wool clothes can be machine washed at 30 C with a special wool detergent and without fabric softener. To prolong the lifespan of Merino clothes, we recommend putting them in a pillow case before washing them. This will protect them from abrasion in the washing machine – also from other garments with buttons, zippers, hooks etc. Read more in the article How to Wash Outdoor Clothing.
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