When you’re hiking in cool weather or varying climates, having a quality base layer you can rely on is a must. Your base layer will have a huge effect on your overall performance, warmth, and comfort, so it’s essential to make the right choice to shield your skin and balance your body temperature.
Merino wool is one of the premier base layer materials on the market, due to its high breathability, lightweight fit, and moisture wicking components. Keep reading to discover what you need to look for when selecting the best merino wool base layer, plus the top 5 choices you’ll want to consider incorporating into your hiking apparel.
The top 5 merino wool base layer we recommend for 2023:
The Top 5 Best Merino Wool Base Layers Review
Check out our top 5 merino wool base layers to see which one you like best! Keep reading for our detailed review of each, plus the final verdict revealing which base layer we declared the clear winner.
Icebreaker Merino Men's Oasis Long Sleeve Crewe Top
- Super comfortable
- Nice slim fit
- Great for layering without feeling bulked down
- Wicks moisture and fights odors
- The arms can run a bit short
- Certain sizes might run a bit large
The first pick on our list is this fantastic choice by Icebreaker, featuring a 100% merino wool design with 200 density. We would say that you could definitely wear this base layer in any season, save for super hot days out on the trail.
We love the fact that the Icebreaker Oasis Long Sleeve Crewe Top is made from pure merino wool instead of a blend, which means that it is incredibly comfortable and light on the skin.
The shirt has impressive odor and moisture fighting capabilities, with an easy slim fit that makes this top the ideal choice for base layering without feeling weighed down. Despite the very slim fit, this long sleeve crewe top still has a fantastic stretch with offset shoulder seams to help you avoid chafing.
SmartWool Men's NTS Mid 250 Crew
- Incredibly insulating
- 250 density fibers
- Great for very cold weather hikes
- Flatlock seams
- Tight fit
- Could stretch with frequent wearing
- A little pricier than some other option
Our next pick features 250 density, making the fabric a thicker choice for colder climates and slightly bulkier layering. If you’re going to be hiking on the grid or off in very chilly, winter climates, you’ll love the SmartWool Men’s NTS Mid 250 Crew. We like the insulating qualities of this base layer, plus the pure 100% merino wool material is of the utmost quality.
One thing we would note is that due to the density of the fibers in this shirt, it will take much longer to dry if it becomes wet. The base layer has less moisture wicking capabilities than our previous pick because of the denser fibers, so this is something to be aware of if you’re going to be hiking in damp weather conditions.
However, the tight fit of this base layer is unparalleled, with comfortable flatlock seams and panels in the shoulders for enhanced comfort. For very cold weather, the high insulating qualities of the SmartWool Men’s NTS Mid 250 Crew might be just what you’re looking for.
Ibex Merino Wool Men's Woolies 2 Crew Shirt
- Very soft due to fiber diameter
- Does a good job of wicking moisture
- Keeps you warm and dry
- A good stretch to the material
- Semi-tight fit
- Fabric could be a bit scratchy for some
- May not be ideal if you want a super tight fit
The Ibex Woolies 2 Crew made it to our list for its lightweight, 230 fiber density manufactured from 100% pure merino wool. Because the diameter of the fibers in this base layer is a mere 18.5 microns, the shirt is super soft on the skin.
We were very happy to discover how well this shirt wicks moisture, keeping you nice and dry while fighting the onset of bacteria that cause odors.
We were impressed again by this base layer’s flatlock seam design with a semi-tight fit to give you some bonus warmth in chilly conditions. Another big plus for us is the somewhat stretchy material of the Ibex Merino Wool Men’s Woolies 2 Crew Shirt because it gives you fantastic mobility in all types of hiking conditions. You can select the shirt in 3 neutral shades.
WoolX Explorer LS- Merino Wool Midweight Baselayer Top
- Ultra soft 17.5-micron fibers
- Very simple and durable design
- Quality flatlock seams that won’t cause rubbing or chafing
- Good as both a standalone and layering piece
- Cuffs stay in place even with strenuous activity
- You might need to hand wash as the base layer is more delicate
- Tends to run long
The next pick on our list is also by WoolX, again featuring 230 fiber density. Compared to our previous pick, this baselayer top is even softer to the touch with tiny, 17.5-micron fibers of impressive quality and durability. If you want a simple base layer that will feel extra comfortable and light on the skin, this pick could be the shirt you’ve been looking for.
We were happy to see the flatlock seams and articulated sleeve design on this base layer top, with cuffs made to stay in place rather than ride up if you’re climbing a steep trail or up a mountain.
When the weather is warmer, you can definitely wear this base layer on its own to stay cool and dry. Or, when the weather is very cold, you’ll have no problem layering this piece beneath other insulating clothing to stay nice and warm.
Minus33 Merino Wool 705 Chocorua Men's Midweight Crew
- Drop tail hem
- 230 density fibers
- Superfine 18.5-micron fibers
- Regular fit with excellent stretch
- Stitching can come loose
- Can get holes if washed in the washer
Our final pick is designed from ultra-fine Merino wool featuring 18.5-micron fibers. The material is super lightweight, highly breathable, and feels wonderful to the touch.
We liked the 230 density material that makes this base layer an ideal choice for spring, fall, and winter hikers alike. You’ll also enjoy plenty of mobility with this selection, as it features a regular fit with great give.
One cool feature we noticed is the tagless design, which will save you the trouble of scratching incessantly at annoying clothing tags irritating your skin. We were happy to see flatlock seams in this shirt’s design as well, so you also won’t need to worry about chafing or rubbing. Another nice touch is that this midweight crew includes a drop tail hem so the shirt won’t ride up on a tough trail.
Why Choose Merino Wool?
There are plenty of reasons that merino wool has become the go-to pick for many hikers as a reliable base layer, as opposed to other traditional options such as polyester or nylon. Merino wool is incredibly lightweight on the skin and is definitely a far cry from the scratchy wool sweaters you might have worn as a kid.
The right merino wool base layer is not only exceptionally breathable but wicks moisture like a dream, so you don’t have to worry about nasty sweat and odors distracting you from your hike. Another great feature that you should consider before buying a merino wool base layer is its innate antimicrobial properties.
The moisture-wicking design of merino wool not only keeps you nice and dry but prevents bacteria from gathering as the result of dirt and dampness. Merino wool is also insanely comfortable and feels super soft. What’s more, a good merino wool base layer offers quality UV protection, so if you have skin prone to sunburn, you’ll love this material even more.
Because merino wool is designed from natural rather than synthetic fibers, the material does take longer to dry than a choice like nylon would.
While merino wool is definitely durable, it might not last quite as long as nylon would for strenuous hikes. Merino wool also tends to come at a higher price point than synthetic materials.
That said, you get what you pay for. The breathability, moisture wicking, antimicrobial, UV resistant, and comfortable components of a merino wool base layer could make all the difference for you when you’re out on the trail.
What Should You Look for When Selecting a Merino Wool Base Layer?
Let’s take a closer look at the key features you need to look for when selecting a base layer made of merino wool.
The first feature to pay attention is the seaming of the product. Your base layer seams shouldn’t be uncomfortable where they would lead to chafing or rubbing, thereby irritating the skin. Many companies opt instead to design their base layers with flatlock seams for optimal wearer comfort.
If you’re going to be wearing a fitted base layer like merino wool, flatlock seams are definitely a component to keep an eye out for.
Another key feature to be aware is whether it includes an anti-odor component. When it comes to warding off the unwanted odors that gather after a long, hot hike out on the trail, there is nothing that can compare with the wicking capabilities of merino wool.
The reason for this is that merino wool contains wool wax or lanolin, which fights bacteria and stops resulting odors in their tracks.
While synthetic materials like nylon might sometimes be treated with antimicrobial solutions by the manufacturer, the treatments usually wash out quickly and render the bacteria-fighting components ineffective. So, if you want a base layer that fights odors and keeps you smelling fresh, merino wool is most definitely the way to go.
Naturally, durability is another key factor to bear in mind. As we mentioned previously, despite its many premium features, merino wool is not always as durable as some of the synthetic options available.
With that said, many manufacturers have found a way to combine the extra durability of synthetic material with the quality of wool, producing base layers with a blend of both materials.
As a result, the base layer is still incredibly lightweight and breathable, while offering greater longevity of use that holds up against wear and tear. If you don’t mind replacing your merino wool base layer every few seasons or so, this might not be as significant an issue. Otherwise, keep an eye out for merino and synthetic blend base layers so you can enjoy the best of both worlds.
You should definitely factor the fit of any base layer you consider into the picture before selecting the best one for your needs. Ultimately, fit can have the greatest impact on your performance out on the trail, potentially more so than simply wearing a lightweight material.
While you should take all of the factors previously discussed into account when picking a merino wool base layer, never sacrifice the fit. You should select a merino wool base layer with a snugger fit if you’re going to be hiking in very cold weather. On the other hand, a traditional or loose fit is perfect for warm weather, provided it offers sufficient ventilation.
So, who made it to the top of our list? The decision was close, but in the end, we chose the WoolX Explorer LS- Merino Wool Midweight Baselayer Top. There were so many aspects that we liked about this best merino wool base layer, from its ultra-soft 17.5-micron fibers to its quality 230 density to its lightweight design.
We loved the fact that you can wear this piece as a standalone or layering shirt, plus the flatlock seams and articulated sleeves were just what we look for in a merino wool base layer. With cuffs that don’t ride up even when you’re scaling the loftiest mountain, the WoolX Explorer LS is the perfect choice for any hiking aficionado.