Base Layers and Underwear

The best base layers and underwear, reviewed and curated by the Trailspace community. The latest review was added on January 23, 2020. Stores' prices and availability are updated daily.

Recent Base Layer Reviews

rated 4.5 of 5 stars
Black Diamond Men's 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. (Preliminary review based… Full review

rated 4.5 of 5 stars
Black Diamond Men's 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. (Preliminary review based on the first month of use) Black Diamond’s Solution… Full review

rated 4.5 of 5 stars
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! 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… Full review

rated 4.5 of 5 stars
Kari Traa Rose Pant

The Kari Traa Rose Pant 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! Testing Conditions: I tested the Kari Traa Rose Pant from December 2018 to December 2019 as a member of the Trailspace Review Corps. Testing conditions ranged from -25 to 20 degrees Fahrenheit in… Full review

rated 4.5 of 5 stars
Smartwool Merino Sport 150 Brief

Super comfortable undies, which will help you stay sweet smelling for days, with no chafing. Yeah, I'm reviewing underwear. Being a big Merino fan, I decided it was time to take the final step towards full commitment, by going right down to the basics. I decided to give these a try.   Fit: The overall fit is good. I'd read a couple of reviews criticizing the extra wide waistband, but in my opinion, it makes them much more stable and keeps them in place better than other briefs I've used. I like… Full review

rated 5 of 5 stars
Thinx Classic Undies

Dealing with periods in the backcountry can be incredibly frustrating. But Thinx unswear just might offer a solution. Periods are a regular part of most women's life. And yet they're still taboo to talk about. Instead of weighing all of our options, we pace along the period aisle in the grocery store, opting to use the most popular products (pads and tampons). But what other options are there? And how do you begin to handle periods in the backcountry? As someone who spends a lot of time in the wilderness,… Full review

rated 4 of 5 stars
Houdini Desoli Zip

The Houdini Desoli Zip is labeled as a base layer, but the 150g/sqm weight of the 100 percent Merino wool makes it double as an excellent backpacking shirt. The slim fit combined with the long arms and torso work well with various pack sizes. Soft wool and precise, flat stitching provide wonderful comfort that held up very well to use and abuse. Houdini impressed me with their Alpha Houdi a few years back so I took a chance on a couple of their Desoli Zip Merino wool shirts this year. I meant to… Full review

rated 3 of 5 stars
Minus33 Isolation Midweight Merino Zip-Neck

The Minus33 Isolation Midweight Merino Zip-Neck makes an excellent base layer top. I typically wear this to bed when camping. It helps keep you nice and warm, and is very comfortable. This product makes an excellent base layer. It keeps me nice and warm no matter what I’m doing, whether it's camping or working outside. It’s pretty lightweight but does its job very well. Whenever I’m camping in the summer (I sleep in a hammock) I’m usually good with just wearing a t-shirt with this base layer… Full review

rated 5 of 5 stars
Mont Slinx LS Zip

The single most comfortable fleece base or mid-layer around. I have to say, I've never been a fan of fleece, but this item changed my mind! Also, there is a distinct lack of Australian brands on this site and I think it's time to rectify that. The Mont Slinx LS Zip shirt is a long sleeve "polar base-layer" made from Polartec Power Stretch Pro. The cut is very form fitting, but the material moves with you like a second skin. I first tried this garment when on a guiding trip a co-guide (pictured right)… Full review

user rating: 4.5 of 5 (9)
ExOfficio Give-N-Go Boxer Brief Boxer/Brief/Bikini
$11 - $30
user rating: 5 of 5 (2)
Arc'teryx Rho LT Zip Neck Top
$94 - $125
user rating: 5 of 5 (2)
Patagonia R1 Pants Bottom
$35 - $119
user rating: 5 of 5 (2)
Icebreaker Everyday Long Sleeve Crewe Top
$40
user rating: 5 of 5 (1)
Patagonia Capilene 2 Lightweight Crew Top
$49
user rating: 5 of 5 (1)
Fjallraven Bergtagen Longjohns Bottom
$140
user rating: 5 of 5 (1)
Smartwool Midweight Crew Top
$60 - $100
user rating: 5 of 5 (1)
Icebreaker Siren Bra Sports Bra
$37 - $50
user rating: 5 of 5 (1)
Helly Hansen Warm Ice Crew Top
$45
user rating: 5 of 5 (1)
ExOfficio Give-N-Go Lacy Bikini Boxer/Brief/Bikini
$10
user rating: 5 of 5 (1)
Patagonia Capilene Thermal Weight Bottoms Bottom
$89
user rating: 5 of 5 (1)
Smartwool NTS Mid 250 Bottom Bottom
$95
user rating: 5 of 5 (1)
Fjallraven Bergtagen Woolmesh Sweater Top
$160
user rating: 5 of 5 (1)
Marmot Midweight Crew LS Top
$60
user rating: 5 of 5 (1)
Patagonia Capilene 3 Midweight Bottoms Bottom
$24 - $59
user rating: 4.5 of 5 (1)
Helly Hansen HH Lifa Merino Pant Bottom
$63 - $75
user rating: 4.5 of 5 (1)
Patagonia Capilene Air Bottoms Bottom
$90 - $129
user rating: 4.5 of 5 (1)
Patagonia Capilene Lightweight T-Shirt Top
$20
user rating: 4.5 of 5 (1)
Black Diamond Solution 150 Merino Base 3/4 Bottom
$72 - $95
user rating: 4.5 of 5 (1)
Black Diamond Solution 150 Merino Base Crew Top
$73 - $119
user rating: 4.5 of 5 (1)
ExOfficio Give-N-Go Sport Mesh Brief Boxer/Brief/Bikini
$14 - $26
user rating: 4.5 of 5 (1)
Helly Hansen HH Lifa Merino 1/2 Zip Top
$50 - $105
user rating: 4.5 of 5 (1)
Patagonia Capilene Thermal Weight Zip-Neck Top
$69 - $99
user rating: 4.5 of 5 (1)
Kari Traa Rose Long Sleeve Top
$63 - $99
user rating: 4.5 of 5 (1)
Icebreaker Anatomica Brief Boxer/Brief/Bikini
$27
user rating: 4.5 of 5 (1)
Airblaster Ninja Suit One-Piece Base Layer
$72 - $109
user rating: 4.5 of 5 (1)
Patagonia Capilene Air Hoody Top
$104 - $149
user rating: 4.5 of 5 (1)
Kari Traa Rose Pant Bottom
$63 - $100
user rating: 4.5 of 5 (1)
Smartwool Merino Sport 150 Brief Boxer/Brief/Bikini
$25
user rating: 4 of 5 (2)
Patagonia Capilene Air Crew Top
$90 - $129
user rating: 4 of 5 (2)
Outdoor Research ActiveIce Sun Sleeves Arm/Leg Sleeve
$29 - $34
user rating: 4 of 5 (1)
SportHill Northwind Unders Boxer/Brief/Bikini
$29 - $50
user rating: 4 of 5 (1)
ExOfficio Sol Cool Boxer Brief Boxer/Brief/Bikini
$12 - $41
user rating: 4 of 5 (1)
Patagonia Capilene Daily T-Shirt Top
$39
user rating: 4 of 5 (1)
Terramar Thermolator II Pant Bottom
$15
user rating: 4 of 5 (1)
ExOfficio Give-N-Go Lacy Full Cut Brief Boxer/Brief/Bikini
$12
user rating: 4 of 5 (1)
Outdoor Research Alpine Onset Crew Top
$50 - $68
user rating: 3.5 of 5 (2)
ExOfficio Give-N-Go Boxer Boxer/Brief/Bikini
$26 - $29
user rating: 3.5 of 5 (1)
Outdoor Research Alpine Onset Bottoms Bottom
$44
user rating: 3 of 5 (1)
Minus33 Isolation Midweight Merino Zip-Neck Top
$90
user rating: 2.5 of 5 (1)
Garneau Arm Coolers Arm/Leg Sleeve
$30
user rating: 2 of 5 (1)
Terramar Silk Pant Bottom
$26 - $55
Outdoor Research Enigma Boxer Briefs Boxer/Brief/Bikini
$34
Outdoor Research Enigma Bottoms Bottom
$69
Outdoor Research Enigma Half Zip Top
$79
Smartwool Merino 250 Base Layer Bottom Bottom
$48 - $130
Smartwool Merino 250 Base Layer 1/4 Zip Top
$60 - $115
user rating: 5 of 5 (6)
Patagonia Capilene 2 Lightweight Zip-Neck Top
user rating: 5 of 5 (3)
Icebreaker Bodyfit 150 Long Sleeve Crewe Top
user rating: 5 of 5 (2)
Icebreaker 260 Midweight Tech Top Top
$110 MSRP
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