The Best Merino Wool Base Layers of 2019


Smartwool NTS Mid 250 Crew Top

Smartwool NTS Mid 250 Crew Top

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 great UV protection. 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.

We regularly update our reviews and selections to always recommend you the best products on the market.
This selection includes primarily men's products. For women's products check out the Best Merino Base Layers for Women.

1. 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.

Expert Selections
We only list top-tier products. Read how our selections of best hiking products differ from others here.
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2. The Best Merino Wool Base Layers Review

Best Merino Base Layers

Best Merino Base Layers

The Best Merino Wool Base Layers – List

  1. Icebreaker Oasis Long Sleeve Crewe
  2. Smartwool NTS Mid 250 Crew Top
  3. Woolly Everyday Henley Hoodie
  4. Woolx Explorer
  5. Minus 33 Chocorua

Comparison

Feature/Product Icebreaker Oasis Long Sleeve CreweSmartwool NTS Mid 250 Crew Woolly EverydayWoolx ExplorerMinus 33 Chocorua
Material100% Merino wool100% Merino wool
100% Merino wool100% Merino Wool 100% Merino wool
Fabric Density200 g/m2250 g/m2190 g/m2230 g/m2230 g/m2
FitSlim Form Regular Slim 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 YesYesYesYesYes
Icebreaker Oasis

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:

  • /

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Video

Smartwool NTS 250

Smartwool NTS 250

2. Smartwool NTS Mid 250 Crew

Suitable for:

  • Hiking
  • Mountaineering
  • Trekking
  • Backpacking
  • Climbing
  • Running
  • Everyday use

The Smartwool NTS Mid 250 Crew 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 NTS Mid 250 Crew base layer is best for those who need a base layer for hiking in very cold conditions.

Women's Version: Available - Smartwool Women's NTS Mid 250 Crew

Note: Women's version might slightly differ from the men's version.

 

Pros:

  • Comfortable
  • Fit
  • Warmth
  • Breathable
  • Odor-resistant

Cons:

  • /

Share your opinion and help others!

Do you have this product? Tell us what you think about it and help others decide what to buy!

 

Woolly Henley

Woolly Henley

3. Woolly Everyday Henley Hoodie

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 Hoodie 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. Besides the hood and the Henley neck-line, it is equipped with kangaroo pockets for hand warming or storage. The Woolly Everyday Henley Hoodie is available in four muted colors.

Women's Version: Not available - see the Women's Base Layers instead.

 

Pros:

  • Breathable
  • Moisture-wicking
  • Odor-resistant
  • Quality

Cons:

  • /

Share your opinion and help others!

Do you have this product? Tell us what you think about it and help others decide what to buy!

 

Woolx Explorer

Woolx Explorer

4. Woolx Explorer

Suitable for:

  • Hiking
  • Mountaineering
  • Trekking
  • Backpacking
  • Climbing
  • Running
  • Everyday use

The Woolx Explorer base layer is made of top-quality Merino wool – the fibers measure only 17.5 microns in diameter. Therefore, the base layer is very comfortable to wear and super soft to the touch. The Woolx base layer is made with flatlock seams, printed interior label, embroidered logo and articulated sleeves. The cuffs are specially designed to not ride up during technical activities such as climbing. The Woolx base layer can be worn as a standalone garment in warm weather or layered under heavier clothes in cold weather. It is available in three different colors. The Woolx Explorer is a great option for those want a super comfortable base layer for various outdoor activities.

Women's Version: Not available - see the Women's Base Layers instead.

 

Pros:

  • Quality
  • Comfort
  • Design
  • Breathable
  • Moisture-wicking
  • Odor-resistant

Cons:

  • /

Share your opinion and help others!

Do you have this product? Tell us what you think about it and help others decide what to buy!

 

Minus33 Chocorua

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: Not available - see the Women's Base Layers instead.

 

Pros:

  • Fit
  • Quality
  • Comfortable
  • Odor-control

Cons:

  • /

Share your opinion and help others!

Do you have this product? Tell us what you think about it and help others decide what to buy!

 

 

 

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4. 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 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.

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Post Author

Post Author

Blaz

Outdoor enthusiast with experience in all types of hiking and mountaineering. Hiked in the Alps, Iceland and other countries. In love with via ferrata trails and snow-covered slopes. Check out my hikes.

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