Base Layers and Underwear
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Types of Base Layers and Underwear
Top Picks
How we choose: The best base layers and underwear highlighted here were selected based on 269 reviews of 205 products. Our top picks are those that are readily-available in the United States and have received the highest overall ratings from reviewers.
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Ibex Woolies Tech Bottoms
Versatile lightweight merino blend layer, perfect for winter backcountry use, chilly nights in camp, and just lounging around at home on cold days.
Reasons to Buy
- Soft
- Good fit
- Breathable
- Warm, but not too warm
- Stretchy
- Reasonably quick drying
- Easy to care for
Reasons to Avoid
- It would be nice to have an option for a shorter inseam
I’ve been a huge fan of Ibex clothing for many years. The Ibex Indie hoody I bought probably twenty years ago, is still one of my favorites. I was sad when they announced that they were closing a number of years ago and have been pleased to see that they have returned. I was eager to give these bottoms a try. I received the Woolies Tech Bottoms in late spring when our Northern California weather was generally too warm to use them much initially, but with colder and wetter weather descending on us this winter, I’ve been wearing them a lot. Campground fashion statement rearview Fit and Comfort: The fit of the Woolies Tech Bottoms is as would be expected.
Read more: Ibex Woolies Tech Bottoms review (1)
Smartwool Merino Boxer Brief
Smartwool brings Merino magic with their Boxer Brief. Comfortable, functional, and surprisingly durable these are great for any sort of hiking or backpacking, but especially useful on extended trips when you appreciate the no-stink qualities of good wool.
Reasons to Buy
- Comfortable
- Durable
- Good waistband
- Amazing anti-smell ability
Reasons to Avoid
- Investment
. I have had great experience in the past with Smartwool products having enjoyed their socks and insulating layers. When the chance came up to test their Merino Boxer Brief I had high expectations. Made with a Merino/nylon blend, 150g weight material in a Slim Fit style, they looked and felt great from the start. After a grueling season on trail, including a month-long thru hike of Vermont's Long Trail, I have to admit I liked them even more than I expected heh. Let's get into these briefs...I mean talking about them.
Read more: Smartwool Merino Boxer Brief review (1)
Fjallraven Bergtagen Woolmesh Sweater
The Fjallraven Bergtagen Woolmesh Sweater is a base layer top that utilizes wool in three different weaves to maximize heat retention in key areas (chest, back) and breathability in others (stomach, underarms). It’s a total home run of execution and since I received this top for testing I have worn nothing else. It’s exceptionally well tailored, durable, doesn’t stink on multi-day trips, and you’ll have no fear around a fire. The only possible negatives are more inherent to wool, than this product—it takes longer to dry.
Reasons to Buy
- Comfortable
- Durable
- Breathable
- Sleeve and torso length
- No stink factor
- Tight neckline (keeps snow out)
- Fire resistant (no worry about sparks)
Reasons to Avoid
- Wool takes longer to dry
- No trail to town use
- I usually prefer a base layer with a hood
- I'd love to see thumb loops added
PREAMBLE Fjallraven is right up there with Arc'teryx in the confusing naming scheme of their products. The Woolmesh Sweater is part of their Bergtagen line (Bergtagen is a Swedish word used to describe the feeling of being captivated and humbled by the mountains, awesome name), which includes the base layer (two top options and two bottom options, both men's and women's), mid-layer insulation (two different jackets for both men and women as well as an elephant style sleeping bag), outer shell (pants and jacket, both men's and women's), and a work layer (pants and jacket, both men's and women's).
Read more: Fjallraven Bergtagen Woolmesh Sweater review (1)
Voormi River Run Hoodie
A super-comfortable and versatile Merino blend hooded shirt, excels as a sun or wind shirt. This is the first time I’ve really tried a long-sleeved sun protective shirt, and I was pleasantly surprised how comfortable it is in warm conditions. Though it is marketed as a sun shirt, it is much more than that.
Reasons to Buy
- Soft comfortable hand
- Lightweight
- Breathable
- Great fit
- Versatile
- Machine washable
Reasons to Avoid
- The hem could be a little lower for better coverage of my long waist
- Thumb loops can rub against your hand with hiking poles or handlebars
Morning walk in the foothills Having read several super positive reviews about this hoodie, I wanted to give it a try, but was put-off a little bit by the price tag. But having recently moved to the Sierra foothills, where it is generally colder than the central valley, I went for it anyway, and was not disappointed. Fit and Comfort: I would consider the fit to be on the "athletic" side. I wasn’t quite sure whether to order the XL or the XXL. While I usually fit XL in most shirts, occasionally they can be a little tight (Icebreaker shirts are a good example of this.
Read more: Voormi River Run Hoodie reviews (2)
ExOfficio Give-N-Go Boxer Brief
These might replace every pair of underwear you own. Okay, maybe not at $25 a pair, but they are comfortable, lightweight, incredibly fast at wicking away moisture and quick drying. Yep, they are that good.
Reasons to Buy
- Comfortable, does not ride up
- Unbelievably fast drying
- Wicks away moisture flawlessly
- Anti-microbial treatment keeps stench away
Reasons to Avoid
- Waistband stretches out over time
- Every time I look for them online, I have to look at the midsection of an incredibly toned and tanned young man. Well, I guess that would be a pro for some.
When I purchased my first pair of these in 2009, I would have said $25 is rather expensive for a pair of underwear and would have listed that as a con. Today, as I see other performance underwear being sold for $30-$50, I realize that $25 is reasonable and well worth the investment. If you're a briefs kind-of-guy, they are slightly cheaper ($20). USE: I first bought them because I was bike commuting 8 miles each day in the summer heat and preferred to be dry upon arriving to work. Since then, I have purchased a few more pairs (three in all) and have used for multi-day and day hikes, fishing, hunting, swimming, and just everyday use. THE TEST: These underwear really proved their worth to me when I visited the tropical rainforest island of...
Read more: ExOfficio Give-N-Go Boxer Brief reviews (9)
Patagonia Capilene Air Bottoms
The Patagonia Capilene Air Bottoms are Patagonia’s newest base layer design which utilizes a unique seamless knit construction that is composed of 51 percent merino wool and 49 percent Capilene recycled polyester. This results in a very stretchy insulation layer that is both light and warm. The knit construction provides a nice thickness that works extremely well inside of waders for long days fishing in cold streams. Overall this is a great base layer, especially for colder conditions.
Reasons to Buy
- Very warm
- Not itchy for wool
- Seamless design adds to comfort – very flat transitions
- Doesn’t hold odors
- Nice comfortable waistband
- Responsibly sourced wool and recycled polyester
Reasons to Avoid
- Lack of a fly opening
- Might be too warm for many activities
- Some shrinkage in the pant leg length
- Pills pretty easily
Overview The Patagonia Capilene Air Bottoms are Patagonia’s newest base layer design that follows Patagonia’s long tradition of developing new fabrics with improved performance while also trying to find ways to minimize the impact on the environment. The Capilene Air Bottom fabric is a unique a 3-D seamless knit construction that utilize fibers made from 51 percent responsibly sourced merino wool and 49% Capilene recycled polyester. The resulting bottoms are light, warm and very comfortable to wear.
Read more: Patagonia Capilene Air Bottoms review (1)
Smartwool Classic All-Season Merino Base Layer Bottom
A full-length base layer bottom that has real value on trail in all four seasons. Smartwool's Classic All-Season Merino Base Layer Bottom uses a 150g wool/nylon blend fabric that is heavy enough to add warmth when layered but light enough to use as a hiking tight in warm weather. Comfort and durability for use all year.
Reasons to Buy
- Comfortable
- Durable
- Warm when layered
- Cool worn alone
- Smell fighting wool
Reasons to Avoid
- Lacks support where you'd like it
Taft Lodge on the Long Trail (Vermont) Long a fan of Smartwool layers in winter, I spent this summer testing some of their gear that works well in warm weather. Along with the Merino Boxer Brief, which I wore almost every mile of the season, I also spent some time wearing Smartwool's Classic All-Season Merino Base Layer Bottom. Light in the pack and extremely versatile on the body I found these bottoms to be worth carrying on trips long and short. There is also a women's version of this.
Read more: Smartwool Classic All-Season Merino Base Layer Bottom review (1)
Black Diamond Solution 150 Merino Base 3/4
Black Diamond's Solution 150 Merino Base 3/4 is a lightweight, polyester-reinforced merino wool base layer. Cool enough to wear under light shell clothing for high intensity activity at around-freezing temperatures without overheating, but easily layered over for use in colder conditions or at lower intensity. Stretch fabric gives a comfortable fit even on a slim frame and dries a little faster than 100 percent merino. 3/4 length works with high plastic cuff ski boots.
Reasons to Buy
- Comfy fit and feel
- Light base layer for intensive activity
- Also good for cold-wet days in summer
- Lightweight in the pack
- 3/4 length works with tele and rando boots and saves a little weight
Reasons to Avoid
- Polyester core may shed microplastic fibers in wash water
- No long sizes
(Preliminary review based on the first month of use) Black Diamond’s Solution 150 Base shirts and long underwear are lightweight, polyester-reinforced merino wool base layers. They are light enough to wear under light shell clothing for high intensity activity at around-freezing temperatures without overheating, but easily layered over for use in colder conditions or at lower intensity. BD has supplied me with both a crew neck top and ¾ length bottoms for testing. Much of what I have to say about the one will apply to the other and so may be duplicated in both reviews. The Solution 150 lineup also includes a full length bottom, and all three variants are also available in women's versions.
Read more: Black Diamond Solution 150 Merino Base 3/4 review (1)
Black Diamond Solution 150 Merino Base Crew
Black Diamond's Solution 150 Merino Base Crew is a lightweight, polyester-reinforced merino wool base layer. Cool enough to wear under light shell clothing for high intensity activity at around-freezing temperatures without overheating, but easily layered over for use in colder conditions or at lower intensity. Stretch fabric gives a comfortable fit even on a slim frame and dries a little faster than 100 percent merino.
Reasons to Buy
- Comfy fit and feel
- Light base layer for intensive activity
- Also good for cold-wet days in summer
- Lightweight in the pack
Reasons to Avoid
- Polyester core may shed microplastic fibers in wash water
- No long sizes
(Preliminary review based on the first month of use) Black Diamond’s Solution 150 Base shirts and long underwear are lightweight, polyester-reinforced merino wool base layers. They are light enough to wear under light shell clothing for high intensity activity at around-freezing temperatures without overheating, but easily layered over for use in colder conditions or at lower intensity. BD has supplied me with both a crew neck top and ¾ length bottoms for testing. Much of what I have to say about the one will apply to the other and so may be duplicated in both reviews.
Read more: Black Diamond Solution 150 Merino Base Crew review (1)
Kari Traa Rose Long Sleeve
The Kari Traa Rose Longsleeve is a 100 percent merino base layer that is comfortable, warm, and durable. It's thin enough to layer without restricting movement, and incorporates a range of colors and sizes to appeal to a variety of adventurous ladies! Just be prepared to size up as this base layer runs SMALL!
Reasons to Buy
- Soft (for merino wool)
- Warm
- Breathable
- Fit is snug without restricting movement
- Thin enough to layer easily
- Stays in place
- Variety of color and size options (up to 4XL)
Reasons to Avoid
- Runs small—plan to order one size up
Testing Conditions: I tested the Kari Traa Rose Longsleeve from December 2018 to December 2019 as a member of the Trailspace Review Corps. Testing conditions ranged from -25 to 20 degrees Fahrenheit in the following activities: hiking, fat biking, snowshoeing, backcountry skiing, alpine (resort) skiing, and nordic skiing. Rose Longsleeve front view Fit & Comfort: For those who aren't familiar with Kari Traa, the Norwegian brand was developed by its namesake, a female Olympian freestyle skier. The Rose Longsleeve is a base layer made of 100 percent merino wool.
Read more: Kari Traa Rose Long Sleeve review (1)
More Base Layers and Underwear
Trailspace reviewers have shared 269 reviews of 205 different base layers and underwear. Narrow your search and view more specific base layer recommendations in these categories:
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