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Base Layers and Underwear

Types of Base Layers and Underwear

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Base Layer Tops

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Base Layer Bottoms

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Boxers, Briefs, Bikinis

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Arm and Leg Sleeves

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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Top Base Layer Bottom

Ibex Woolies Tech Bottoms

user rating: 5 of 5 (1 review)

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)

Top Boxer/Brief/Bikini

Smartwool Merino Boxer Brief

user rating: 5 of 5 (1 review)

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)

Top Base Layer Top

Fjallraven Bergtagen Woolmesh Sweater

user rating: 5 of 5 (1 review)

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)

Base Layer Top

Voormi River Run Hoodie

user rating: 5 of 5 (2 reviews)

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)

Boxer/Brief/Bikini

ExOfficio Give-N-Go Boxer Brief

user rating: 4.5 of 5 (9 reviews)

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)

Base Layer Bottom

Patagonia Capilene Air Bottoms

user rating: 4.5 of 5 (1 review)

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)

Base Layer Bottom

Outdoor Research Enigma Bottoms

user rating: 4.5 of 5 (1 review)

The Outdoor Research Enigma Bottom is a base layer whose forte is wicking moisture and keeping you dry when you’re active; though the fabric has some wool content, it’s mostly synthetic (12% merino, 88% polyester). The fabric is relatively thin and very stretchy and slightly prone to pilling in high-friction areas. It’s an outstanding option for high-output cool and cold weather activities (four-season if you live in a cooler place), except you’ll want to wear them under a shell or fleece when it’s really cold.

Reasons to Buy

  • Moisture handling
  • Comfort
  • Stretchy, great range of motion

Reasons to Avoid

  • Prone to pilling
  • Not as warm as layers that are heavier-weight or that have more wool

BASIC INFORMATION Outdoor Research's Enigma base layers are a combination of wool and polyester—12% merino and 88% Drirelease polyester. Check out my recent reviews of the Enigma Half Zip top and Boxer Briefs. The synthetic part is Outdoor Research's DriRelease E.C.O., "Environmentally Correct Origins,” which is made from 100 percent post-consumer recycled PET, the material used to make plastic bottles and containers, and blended with natural fibers like wool. The bottoms have a one-inch wide elastic waistband, a fly, and a couple of seams mid-leg that run roughly above and below the knee.  FIT AND FEEL The Enigma Bottoms are true to size—you can rely on Outdoor Research's size chart.

Read more: Outdoor Research Enigma Bottoms review (1)

Base Layer Top

FORLOH Deep Space Half Zip Long Sleeve Top

user rating: 4.5 of 5 (1 review)

An impressive, USA-made quarter-zip synthetic baselayer that somehow doesn't get stinky, even after sweaty hikes in the mountains. With excellent moisture-wicking properties and an athletic feel, this baselayer is comfortable and ready to go on all-day adventures in the autumn or winter. While the camo-pattern is targeted toward hunters, it appears the company will be releasing solid color options too, making it more appealing to non-hunting pursuits like hiking, backpacking, skiing, snowshoeing, ice fishing, etc.

Reasons to Buy

  • Wicks moisture very well and dries quickly
  • Exceptionally comfortable
  • Doesn’t stink (which is pretty impressive for a polyester/spandex top)
  • Great movement
  • 50+ UPF rating for sun protection
  • Made in the USA (fibers and construction)

Reasons to Avoid

  • Expected it to be warmer
  • Flimsy collar
  • Torso could be a little bit longer (but my torso is longer than average)

Conditions: My initial test of the FORLOH Men's Deep Space Half Zip Long Sleeve Top has included wearing it regularly for 6 weeks, mostly during deer scouting trips and hunting season for whitetail deer. During the 14 days of traditional deer season here in Pennsylvania, I was afield for 10 of them, wearing this baselayer each time. I also wore the layer on two dayhikes during this test and out to shovel snow after a winter storm. The shirt was worn on long, physically tiring days of traversing rocky ridges and on long, mentally tiring days of sitting still for hours on end in hopes of a deer walking by.

Read more: FORLOH Deep Space Half Zip Long Sleeve Top review (1)

Base Layer Bottom

Smartwool Classic All-Season Merino Base Layer Bottom

user rating: 4.5 of 5 (1 review)

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)

Base Layer Bottom

Black Diamond Solution 150 Merino Base 3/4

user rating: 4.5 of 5 (1 review)

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)

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:

Base Layer Tops

Base Layer Bottoms

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Arm and Leg Sleeves

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